Exploring the Science Behind Companion Animal Health
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S01 E12: Research Director to Director
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- Dr. Carrie Finno: But it was driven by a donor's idea. And I think some of that, you know it might come from the clinic when we're in the clinic, or it might come from someone sitting across from you saying, how do we do this in horses? How do we do this in dogs? How do we do this in cats?
Dr. Michael Kent: Hello, and welcome to today's episode of The Vetrospective. This is your host, Dr. Michael Kent. Today is going to be a little different. I've invited Dr. Carrie Fino here to talk about research. Now, I know we touch on research in almost every episode, but today we're going to the nuts and bolts of research and the impact it has. So, I am director of the Center for Companion Animal Health, which is focused on dogs, cats, birds, rabbits, all companion animals except horses. Dr. Finno is my counterpart at the Center for Equine Health at UC Davis for all things equine. So, Dr. Finno did her undergraduate work at Emory in Georgia and then her veterinary school and her large animal internship in medicine at the University of Minnesota. She then did her residency in large animal medicine and her PhD in comparative pathology here at UC Davis. From there, she held a postdoc position at the University of Minnesota and then was hired an assistant professor there before returning to UC Davis as a faculty member in equine genetics. Dr. Finno became the director for the Center for Equine Health in 2016. She has mentored multiple undergraduate, veterinary students, residents, and graduate students, and has published over 140 peer-reviewed studies. Pretty cool. I could go on with the list of her awards and grants she has received and the list of her accomplishments, but then we wouldn't actually get to speak with her. So, thank you for joining us today, Dr. Finno.
Dr. Carrie Finno: Thanks for having me, Dr. Kent.
Dr. Michael Kent: So, before we dive into this topic of research, I like to ask this question, why veterinary medicine?
Dr. Carrie Finno: That's a great question. I always wanted to do something with horses. And when I was younger, I actually wanted to be a horse trainer, I think as many young girls do. And my parents very wisely said, if you want to do something with horses, maybe consider the medicine side instead of the training side. And so I got kind of set on an idea of being an equine veterinarian, but I...
Dr. Michael Kent: How old were you then?
Dr. Carrie Finno: I was probably about 8 or 9.
Dr. Michael Kent: Yeah.
Dr. Carrie Finno: And I had no idea about research, though, right? Like when you learn that you're going to go to vet school, you want to go and treat animals. So, my vision was I would drive around in a truck and be an equine vet. And then I got to school and I thought maybe I should be a surgeon. But that was an awful idea for me. I don't have that skill set at all. So, I married one instead. But I got the chance to actually run horses on the treadmill during vet school. So, my second year of vet school, there was a job opening with Dr. Stephanie Valberg, and it was to run horses on the treadmill. And I thought, what this is the coolest job anyone could ever have.
Dr. Michael Kent: Yeah.
Dr. Carrie Finno: No interest in research or genetics, and that's how I got involved in it all.
Dr. Michael Kent: Running on a treadmill or have the horses running on a treadmill.
Dr. Carrie Finno: Definitely not me. That'd be awesome.
Dr. Michael Kent: So what kind of research were they doing running horses on a treadmill?
Dr. Carrie Finno: So Dr. Valberg studies inherited muscle disease in horses. So, she actually had a herd.
Dr. Michael Kent: I see the genetic link coming.
Dr. Carrie Finno: There it is. And I was awful. Like genetics undergrad, I got a C+. It was all flies and worms and not my cup of tea.
Dr. Michael Kent: Drosophila.
Dr. Carrie Finno: Yeah. Had no interest in genetics.
Dr. Michael Kent: Or peas, right? Isn't that Mendelian?
Dr. Carrie Finno: Definitely peas, right?
Dr. Michael Kent: Peas, lots of peas.
Dr. Carrie Finno: But when you apply it to horses and you have these families of horses with these inherited muscle diseases, it just made sense. It was cooler and I got completely wrapped up.
Dr. Michael Kent: And it was clinically applicable.
Dr. Carrie Finno: It was very clinically applicable.
Dr. Michael Kent: So, I'm going to take us back and jump a little bit kind of broader picture. Why do we need research for society? What, in general, why do we need research? Why, what is your perspective on this?
Dr. Carrie Finno: So, I think the only way to push the envelope, right, the only way to discover new ways to diagnose diseases, to treat diseases, and I think for all of us to prevent diseases in the first place is with research. And whether that's, you know, basic research that you think about in a lab with somebody holding a pipette, doing things in cells, or like we do where we treat animals with diseases and we see if that can help people or clinical trials in people. There's all these different levels, but until you test those things and ask those questions, you can't move the field forward. And for all of us that have had ourselves or our loved ones with some illness or something where we just really were hoping there was a new treatment, this is the way forward.
Dr. Michael Kent: No, it's I hear you and it resonates well with me because I know, you know, you, like I said, are a center director. And can you explain what the role of a center is within the university like here? What is a center for equine health? What are your goals?
Dr. Carrie Finno: I mean, we are so fortunate. I know you and I have talked about this, right, to have centers. So, UC Davis is incredible in that there was the foresight to develop these species-specific centers where the focus is to actually do research in the species we're supporting. So, a lot of times we talk about translational research, right, where we look at something in the horse, something in the dog, something in the cat that can help people. But a lot of us are really interested in doing research in horses for the sake of diseases in horses. And there's not a lot of funding for that, right?
Dr. Michael Kent: No
Dr. Carrie Finno: And so to have these centers where they are completely philanthropically supported, and we can do that kind of research for the sake of the horse, the dog, the cat, the llama, the alpaca, right? But also a lot of it does translate to humans. It's kind of it's kind of a, you know, double bang for your buck, so to speak.
Dr. Michael Kent: And you mentioned translational research. I know we also have basic science research and we have clinical research. Can you kind of explain what each of those are and how one can lead to the other?
Dr. Carrie Finno: Yeah, so each of those has a really important role. So, when we think of basic research, we think of fundamental questions, right? And in my case, in my lab, one of the things we're really interested in is vitamin E in horses and also in people, right? And so how does vitamin E protect the nervous system? That would be a very basic question. You could take cells, you could take mouse lines, and you could try to figure this out. And then you've got the clinical question, right? And for me, that's why are there some horses that vitamin E deficiency completely impacts more than others? What's the genetics underlying that? So now we have a clinical question we can answer in horses. And then you take it a whole other level, and there's people that have inherited genetic mutations that are vitamin E deficient, and they need very high doses to not develop neurologic disease. So now you have a disease in people that you've also studied in horses that started maybe way back when with mice and with cell lines.
Dr. Michael Kent: And you need that basic mechanism to be able to figure out the problem and then how to tackle it. Do you find, have you found that the genes in people are the same quote unquote genes in horses?
Dr. Carrie Finno: Yeah. I mean, the great thing about genetics, and I always, my students will tell you I'll dork out on this a little bit, but there's four letters. There's ACTG in genetics and every single species has the same letters. So,
Dr. Michael Kent: There's only four of them, right?
Dr. Carrie Finno: There's only four. There's lots of combinations of the four. But It's amazing that you can have a disease in people and that same gene is implicated in horses or dogs or cats, and you can learn so much. I mean, we can learn from humans, but they can learn from our species of interest too.
Dr. Michael Kent: I was asked kind of an interesting question and something that I didn't really understand the question in some ways when it was asked to me by someone who was thinking if they should give money or not for research. And they asked me, how do you separate interesting from actionable research? What's your take on this?
Dr. Carrie Finno: That's a great question because I always say the research isn't complete until we bring it back to the pet owner, the horse owner, the veterinarian, whoever the end person is where there's going to be that impact. And that can be at a basic research level, right? The who cares? You have to be able to answer it for every project you do. If I walk into the lab and I say, why are you doing this? Who cares? You need to have an answer for me and you need to have a target group for who cares. And if you can answer that, that's why you're doing it, right?
Dr. Michael Kent: That’s actionable.
Dr. Carrie Finno: It may be 10 years, right, before you get a test or this, but you're on your way versus, and I do think we all fall into that, right? As researchers, sometimes for you, it's so interesting and you get so involved in it. But if nobody other than you cares, right, you really should direct your your effort into something that's going to help society and individual folks.
Dr. Michael Kent: Yeah, when I first heard that, I went, well, a lot of times what I'm interested in is what I'm doing research on, but it may not be actionable yet because I don't know what the answer is going to be. So sometimes you need to also do a little bit of the research to find out is this a path we need to go down? And sometimes you have to flip the question or think outside the box in order to find out if it will be actionable, too. I like your take on it, though. I think you were thinking of it probably more how she was.
Dr. Carrie Finno: The other side of that is when it starts in the clinic, right? When you have a problem, you have a dog, you have a cat, I have a horse that comes in.
Dr. Michael Kent: I see a problem.
Dr. Carrie Finno: I can't solve that with the tools I have. So how do I go back to that basic science to answer that question? So, I think you can bring it up both. both directions, but the who cares is really important.
Dr. Michael Kent: No, it's essential. And this gets a bit more to the question of what we decide to fund given limited resources. So, you know, you have a limited amount of money and you have proposals. How do you, how do you, I know how my center runs. How does your center run in deciding how you divvy out funds?
Dr. Carrie Finno: So we, just like the Center for Companion Animal Health, we have a scientific advisory board. So, we have a group of faculty, many are at UC Davis. We also have outside equine veterinarians that serve on that board. They honestly, they bring a lot of the who cares to the discussion. And we sit and we go through every single proposal. They're reviewed and they're scored, and then we discuss them. And the way we score them, so significance and innovation, right, that's important. But for us, impact actually carries the biggest score. And you could still have a study that's very basic science, but if you can answer that question, the impact in the clinic…
Dr. Michael Kent: Could be huge.
Dr. Carrie Finno: Could be huge, right? So, you're going to get a very high score on that because it is impactful, even if it's not immediate. And having that outside perspective, I've had a lot of the equine vets that have sat on there and they said, well, the science, I agree with you guys, the science is really good, but we'll never use this. And for us, then that's not worth putting, right, this limited amount of money towards. We need it to be something that equine vets are going to use for their clients.
Dr. Michael Kent: So now I have an answer for this for myself and you decide to take the center director role on. I'm going to ask you why. You know, we all have our own clinic. We all have our own research projects we want to do. Like, it's not easy. You've got to raise the funds. You've got to figure out the process to deliver it. You've got to like push research agendas. So why are you doing it?
Dr. Carrie Finno: It's a great question. And there's two reasons. So ,one is I've been passionate about horses and research and pushing the agenda for since I was 8, right? Since we start at the beginning, right? So that's that passion has been there. But as you said, it's a lot of work. And there is a degree of pay it forward in this profession. And I think that that's across a lot of professions, but we feel it really strongly here, right? So I had, I talked about Dr. Valberg as a mentor in vet school. When I came to UC Davis, Dr. Greg Ferraro was the director for the Center for Equine Health. And as a resident, I walked in and I asked for support to do a lot of projects. I was excited about research and he supported me. He provided the enthusiasm. He provided the funds. And I just saw this incredible machine and opportunity, right, where you could push equine medicine forward. So, Dr. Ferraro never asked a thing of me until he asked me to take the role of center director. And I couldn't really say no to that. So those two reasons.
Dr. Michael Kent: I had a very similar experience with Dr. Pedersen.
Dr. Carrie Finno: I know you did.
Dr. Michael Kent: Yes. And he told me he couldn't retire until he found someone who loved the center as much as he did. And as a resident, when we were needing a linear accelerator and all of a sudden I am a second year radiation oncology resident and deciding what linear accelerator is going into our new cancer clinic. And he was funding it, you know, and my first project that I did, I was doing research on looking at angiogenesis or new blood vessel growth in thyroid tumors. Guess where I got my funding? Center for Companion Animal Health. So, I do hear that pay it forward thing. And I think one of the unique things about Davis is our funding, that we have this intramural funding that can help you start. You know, and you get to ask those questions, that actionable research, If it works, it's really going to work. But maybe an outside funding group in a really competitive area is going to go, that's a stretch. But sometimes the magic happens, right?
Dr. Carrie Finno: Yeah, we can do the high risk, high reward. And then we can make pilot data for those stronger grant applications, right? Sometimes you need a smaller amount of money to just get some data to say, hey, bigger granting agencies, this is worth putting your money towards. And we can do that here.
Dr. Michael Kent: Can you give me an example of research in horses from your center where it's made a big difference?
Dr. Carrie Finno: So, I think one of the fields we've been most impactful for is a lot of the infectious disease work on equine herpes virus, myeloencephalopathy. So Dr. Nicola Pusterla is our…
Dr. Michael Kent: So, what is that disease first?
Dr. Carrie Finno: Yep. So, herpes virus, right, in any species comes with a bad connotation…
Dr. Carrie Finno: As it should. As it should.
Dr. Carrie Finno: Yes, as it should. So, in horses, this particular virus can cause either respiratory disease, it can cause abortion in pregnant mares, or the one we're all scared of is it can cause this awful neurologic disease in these horses. And it is highly contagious.
Dr. Michael Kent: I was like, is that the one that could also jump to people?
Dr. Carrie Finno: That one can't, thankfully, thankfully. Venezuelan can, but not this one.
Dr. Michael Kent: That one does not.
Dr. Carrie Finno: But this one is the one that'll shut down horse shows. So, if there's one affected horse, there've been a lot of worldwide outbreaks, it effectively shuts an entire horse show down, which is millions of dollars. And you've got the risk of these amazing athletes now having a potentially fatal disease. So, Dr. Pusterla really kind of led the game, I think on a lot of this EHV-1 as we call it, equine herpes virus 1.
Dr. Michael Kent: And he's one of our faculty in internal medicine. So, he's an infectious disease specialist.
Dr. Carrie Finno: Exactly. Equine internist. And all of the work he's done on biosecurity and how we would control for this and how we need to be careful about this actually came in handy a few years ago. There was an outbreak down at Desert Horse Park, which is the big facility in Southern California that has huge horse shows. And the CEO at the time of that facility reached out to Davis and said,
Dr. Michael Kent: We have a problem.
Dr. Carrie Finno: We have a problem, and I don't know what to do about this. And Dr. Pusterla, myself, Amy Young from our center, we all got on a plane. We went down there. We helped him manage it. We collected samples at the same time for a graduate student.
Dr. Michael Kent: And this is all because of the research that was done previously.
Dr. Carrie Finno: So, it has made a huge difference in managing those and also educating folks, right, that have these horses that are exposed as to why we're there.
Dr. Michael Kent: So, I know from my center, donors really are our lifeblood. We're 100% funded by our donors. You know, we have no state money. We don't have university money. I mean, there just isn't that available. So, I believe it's pretty much the same for you, right?
Dr. Carrie Finno: It sure is.
Dr. Michael Kent: So why do you think people donate to support animal research?
Dr. Carrie Finno: I think a lot of people, if they've had, in our case, right, a horse that's experienced some disease that we don't know a lot about, and they've had that kind of personal interaction with it, they want to move the field forward, right? They want to have their horses experience help the next animal that comes in. So, I think that's a big piece of it. And then the other part that we have at the center, which is really unique, is we have 150 horses that live there. And they're horses that are owned by the university. They've been donated for a variety of reasons, lameness, some have neurologic disease, some have, we have a horse with narcolepsy. I call them very lovingly my herd of misfits from time to time. But those horses not only teach the veterinary students, but they allow us to kind of examine some of these questions in horses that really at that stage had no other purpose for their owners, right? So, we're a bit of a sanctuary for these animals, and yet we can do this teaching and this really integral mission. So, in addition to the research, we have to support the 150 horses. And I always joke, my dad used to say when I was younger, he's like, you always wanted to have 150 horses.
Dr. Michael Kent: And now you do.
Dr. Carrie Finno: And now I do. It's a lot, but protecting those herds and the value of those herds is near and dear to my heart.
Dr. Michael Kent: Yeah, and that's where our centers are a little different. I don't have 150 dogs here. I might have 150 cats at home, no, just two, and only one dog. But no, I think it's a unique thing again about Davis that we're actually able to support a sanctuary teaching group.
Dr. Carrie Finno: Exactly.
Dr. Michael Kent: Yeah. And can you give me an example where a donor has really impacted your program? So, what came out of their investment basically?
Dr. Carrie Finno: So, we can talk about the large farm we acquired.
Dr. Michael Kent: That was my softball to you, because I was thinking Templeton Farms and you could tell me what that is.
Dr. Carrie Finno: Is that amazing or not. And it was from one of our alums.
Dr. Michael Kent: You're glowing right now, actually.
Dr. Carrie Finno: I am. I just love this part so much, right? So we had One of our veterinary alums who graduated from here who had a client down in the Paso Robles area who had decided that she was going to leave California and was thinking about selling her farm. And this vet, UCD grad, said, you know, what about considering potentially donating it to UC Davis because we run an import program for horses and we can potentially have those horses down there.
Dr. Michael Kent: And so the import program, I know that's a quarantine type facility. Why do we need that?
Dr. Carrie Finno: So, that is actually from the federal government, that's USDA mandated, that horses that come into the United States from other countries have to go through a quarantine to make sure they don't have any infectious diseases. And then the quarantine we do, we kind of lovingly call it the STD quarantine. It's for venereal disease in horses. So, it's for mares and stallions, and we have to test them and make sure they're negative because If they were to get into the breeding population with that disease, it could be devastating.
Dr. Michael Kent: Yeah. So back to Templeton Farms.
Dr. Carrie Finno: So, we run that. And this particular donor had imported horses before. She had horses come through Davis. And she knew that-
Dr. Michael Kent: Yeah, we're in Northern California.
Dr. Carrie Finno: We're in Northern California, right? The horses come into LA, they have to come all the way up to Davis, and then most of them go back to Southern California. So, the idea of having this farm and potentially using it for that purpose was tremendous. So, they reached out to us a few years ago and we drove out there. It was Associate Dean Pascoe before his retirement and myself. And I will never forget driving down the driveway. And this farm, I have never seen anything as nice as this farm. And I looked at him and I was like, if we don't make this work, and he just said, calm down, it's going to be a lot of steps. We might not make this work. And I said, we have to make this work.
Dr. Michael Kent: And you did.
Dr. Carrie Finno: And we did. And it is so nice to have a footprint in central California for our equine program.
Dr. Michael Kent: No, I think it's pretty amazing. Now, I know your center like mine also helps fund equipment and research equipment. And so that may also get used in the clinic sometimes. I know, for example, you supported the first PET scanner for horses. So, can you tell me a little bit about this? What's the process and what's been accomplished by your support of research equipment?
Dr. Carrie Finno: Yeah, the PET scanner is an amazing example. So, for those of you that don't know about the technology, it's positron emission tomography. You probably talked about it here before.
Dr. Michael Kent: I don't think yet, but you know, anything with antimatter in it is way cool, right?
Dr. Carrie Finno: My gosh you’re such a dork.
Dr. Michael Kent: I’m a radiation oncologist. What do you want?
Dr. Carrie Finno: No, true. So, PET scanners, so a lot of us from, you know, the human field know it for cancer, right? Is when you're looking for metastasis screens, you might get a PET scan. And it's they inject you with an isotope that labels certain cells, and then you can kind of image them. So, for horses, there was a question many years ago of, could we do this as kind of a test of functional, right? You have a horse that's lame, we can get a CT, we can get an MRI, you might see some changes there, but there might be a lot of changes in which one is actually-.
Dr. Michael Kent: But are they significant? Do they mean anything?
Dr. Carrie Finno: Making that horse lame. So, if you have a marker that lights up, you could say, hey, it's right there, that's the problem. So, Dr. Mathieu Spriet was actually the one that spearheaded that research and was looking for some initial pilot funding to see, could we take a human PET scanner, which is actually used for brains and people, could we anesthetize a horse and put their leg through it because it was big enough? And so we did. We were able to pilot that.
Dr. Michael Kent: And it was a small, portable one, actually.
Dr. Carrie Finno: Yeah.
Dr. Michael Kent: That actually came here because of a study I was doing on dogs, and we didn't have a PET scanner yet. And this was a spin-off of someone from NIH, and this was... this PET scanner was being developed to be portable to take it to people in nursing homes to look for Alzheimer's.
Dr. Carrie Finno: That's amazing, yeah.
Dr. Michael Kent: And Dr. Sprier walked by and he's like, hey, I could put a horse leg in that. I'm like, talk to him.
And he did.
Dr. Michael Kent: And he did. But so, you had this idea or he had this idea and brought it to you. And I mean, I know it took hundreds of thousands of dollars…
Dr. Carrie Finno: Yeah. And it was actually, Dr. Claudia Sonder, she was a director before me. She started it with Dr. Spriet and her and I talked about it and she's like, “I know this is a gamble, but if this works”, and I said, “if it works, it'd be amazing”.
Dr. Michael Kent: And has it worked?
Dr. Carrie Finno: And it's worked.
Dr. Michael Kent: Softball question again.
Dr. Carrie Finno: Yeah. And now we've got a standing PET for horses. And now there are, I think, over 10 now within the world, but UC Davis was the first place to have this.
Dr. Michael Kent: Well, and it was a human device that we brought back for horse use, which is pretty cool when humans are the guinea pigs for our patients, right?
Dr. Carrie Finno: Yep, sometimes it goes in that direction.
Dr. Michael Kent: You know, we get asked sometimes if we're doing animal research, does that mean we're hurting the animals? And it's like, you know, sometimes we use people as the guinea pigs, right?
Dr. Carrie Finno: Exactly.
Dr. Michael Kent: Yeah. And so, how do you take an idea, something you see in the clinic, how does it become a project? How do you think about it? What's that process for you?
Dr. Carrie Finno: I think for me, a lot of it is actually really donor driven. You know, I spend a lot of time talking to people that are really passionate about a topic, right? And then my goal is to kind of matchmake them, right? As is yours with one of our faculty that's working in that field and see if that synergy together can bring a project.
Dr. Michael Kent: Does it align? Yeah.
Dr. Carrie Finno: And we have, you know, the other example we have is the precision medicine project out at CEH. So, we had a donor that I had this whole plan. I thought he wanted to fund stem cells. I had a whole proposal. I went in. And he sat down and said, how do we do precision medicine in horses?
Dr. Michael Kent: And you threw out your plan and said, let's think about this.
Dr. Carrie Finno: Yeah. And so we ended up, I mean, that herd I told you about those 150 horses, 100 of them have their whole genome sequenced and they have their microbiomes profiled. You know, we got a manure sample and looked at all the bacteria in their gut. They have their metabolites profiled. So, they've become this incredible, but they're even more valuable than they were initially, right? Because we have all this information on them, but it was driven by.
Dr. Michael Kent: And you're now following them.
Dr. Carrie Finno: Yeah, and we have longitudinal data, exactly.
Dr. Michael Kent: Longitudinal, in other words, data over time.
Dr. Carrie Finno: Over time. But it was driven by a donor's idea. And I think some of that, you know, it might come from the clinic when we're in the clinic, or it might come from someone sitting across from you saying, how do we do this in horses? How do we do this in dogs? How do we do this in cats?
Dr. Michael Kent: Yeah, no, I think sometimes we get so caught in our day-to-day, we may not think a little bit differently sometimes. And sometimes it just takes a little help from the outside. And it doesn't hurt if they've got funding to help you do it.
Dr. Carrie Finno: Yeah, we say, well, this is how we do it. This is what it would cost. And they say, done. That's amazing. It's just so powerful.
Dr. Michael Kent: So, I mean, I hope we've kind of gone through a bit of the process of how we think about research, how we take something there and the importance of it, what it means for veterinary medicine. What else should have I asked you?
Dr. Carrie Finno: I think we touched on a lot of things. I think at the end of the day, one of my favorite things to do is walk people around and introduce them to the horses that we have out at the center and talk about everything that we've learned from that horse and how it's changed what we're doing in the clinic and what we're doing with the next patient that comes in. And I mean, I can't say enough about the value, right, in being able to do that, to train veterinary students on actual horses that have certain conditions, and then to also learn from those conditions, so similar to what we see in the clinic, these dogs and cats coming in, and if we can treat it with something new and it's gonna help across species and humans, hopefully too, that'd be amazing.
Dr. Michael Kent: Yeah, or maybe something you learn on a horse we bring back to a dog, you know?
Dr. Carrie Finno: Exactly
Dr. Michael Kent: It is one health...
Dr. Carrie Finno: It really is.
Dr. Michael Kent: We're many species, but really, we share a very similar biology.
Dr. Carrie Finno: Yeah, exactly.
Dr. Michael Kent: Yeah. All right. Anything you want to ask me?
Dr. Carrie Finno: Oh, good. I get to turn the tables now. This is kind of fun for me.
Dr. Michael Kent: Why not? Why not?
Dr. Carrie Finno: So what do you feel like for CCAH has been maybe the biggest hurdle or the biggest challenge that you've overcome in the past few years?
Dr. Michael Kent: Biggest challenge or hurdle we've overcome? That's a really good question. Now I'm stalling, right? You know, I guess our funding sources have always been the issues and probably, you know, the need when we bring new faculty in to be able to help them start their career and start a new lab and making sure they have the resources to do it. You know, I want to make sure our next generation that comes in has the same opportunity I did, and that's not cheap. So, trying to make sure we have the resources in hard economic times when we're not getting the same kind of campus or state support because the money's not there, we've got to find it. And that's been some of the challenge. I think part of the challenge also is what's our next big topic? What's our next big push? You know, we've had such success with our FIP treatment program that Dr. Pedersen started, and now we've got a whole team working on the vaccine for it. And I'm always like, okay, this is our success. What's our next one? You know, our group's been working on trying to make monoclonal antibodies for dogs. And it's, I literally sometimes wake up at night and I'm, I can't fall back asleep sometimes because I'm thinking, last night I woke up and I had a dream that a friend's dog came down with hemangiosarcoma and then I had to euthanize it, which is pretty horrible, right? And so this is, I don't even know what time it is, but so now I'm thinking about the problem of that because today I was meeting with some really lovely people who are helping fund initiatives on hemangiosarcoma. So, now I'm trying to think of how do we treat this better? You know, and we've got grant calls out for it. So, I guess the biggest problem is making sure we stay relevant, making sure we continue to fund the cutting-edge research, and that we still are able to come up with the resources to be able to support all the people here. And sometimes that's what I worry about.
Dr. Carrie Finno: Yeah, I think you and I have that in common.
Dr. Michael Kent: Yeah. Well, I really appreciate you spending the time with me today. And Maybe we'll have to have you back to talk specifically about equine genetics.
Dr. Carrie Finno: Oh, I would love that.
Dr. Michael Kent: Yeah, no, I would love that too. So, thank you very much.
Dr. Carrie Finno: Thanks for the invite.
Dr. Michael Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe Unti. Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E11: Raising Orphan Kittens
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- Dr. Karen Vernau: It's a condition that they're born with. I think it's just been under-recognized because we aren't, in our profession, we're not looking at a bunch of kittens that little and looking at them that carefully. And when you do, you see it.
Dr. Michael Kent: Hello, and welcome to The Vetrospective. This is your host, Dr. Michael Kent, and today we'll be talking about kittens. What do you think of when you think of a kitten? A small ball of furry fun? Soft and cuddly? Well, you'd be right. But they're also a bit fragile compared to their older selves and have special needs. They also face medical problems that are more common than in full-grown cats. And we're going to talk about this and maybe why kittens are different than puppies a little. And we need specialized care and equipment to care for them. While we do not have pediatric experts per se in veterinary medicine, our guest today is about as close as you can get to one. I wanted to welcome Dr. Karen Vernau to join us today to talk about kittens. Dr. Vernau is a clinical professor of neurology and neurosurgery and is a member of the Access to Care service at UC Davis. She graduated from veterinary school from the Ontario Veterinary College at the University of Guelph in Canada. And she did her residency in neurology here at UC Davis, where she then stayed on as faculty. She has an interest in feline neonatal medicine and strives to improve the health and welfare of kittens. Thank you, Dr. Vernau, for joining us today.
Dr. Karen Vernau: Thank you for having me, Dr. Kent. It's nice to be here.
Dr. Michael Kent: Thanks. So my first question for you is one that I pretty much ask everyone. So, what got you interested in veterinary medicine?
Dr. Karen Vernau: Veterinary medicine. I grew up in a household with a single mom and my sister, and she just had a lot on her plate, so we could never have pets. So, I was kind of drawn to my friends' and family's pets, and I loved them. So, I loved them and wanted to have them and wanted to help them in life. So that's kind of what got me started. And my grandmother always wanted to be a veterinarian, but at that time, women couldn't go to veterinary school. So, I think she really inspired me to to do that and to try and make a difference.
Dr. Michael Kent: That's really cool. And then you've obviously become a neurologist. And why neurology? Like I always ask, I'm always interested to know why someone chooses a particular area of veterinary medicine.
Dr. Karen Vernau: I am one of those weirdos that really liked it at school. You know, I went to school at OVC and our professor was French. So, we sort of learned neurology in half French. It was just really fun.
Dr. Michael Kent: The Ontario Veterinary College, right?
Dr. Karen Vernau: Yeah, it's in Guelph, in Ontario.
Dr. Michael Kent: Ontario.
Dr. Karen Vernau: Yeah, so English speaking, but she's, she was French.
Dr. Michael Kent: But she was French speaking.
Dr. Karen Vernau: Yeah, she was hilarious. So, it was really fun and I loved all the puzzles and putting it all together. And it's nice liking something that other people don't like. Right? You must feel that.
Dr. Michael Kent: No, I mean, I'm an oncologist and people think that's odd sometimes. So, but for me, it's my passion in my life, right?
Dr. Karen Vernau: And it's a lot of physics probably for you.
Dr. Michael Kent: There's a lot of physics in radiation oncology and I actually have always liked math. I've liked physics and, you know, it allows me to bring in my 2 backgrounds in a sense, my love of medicine and my more, you know, physics, mechanical type side too.
Dr. Karen Vernau: Yeah.
Dr. Michael Kent: So I know you've been fostering kittens yourself for more than 10 years, probably a lot longer now. And is this what sparked your interest in feline pediatrics and neonatal medicine? What drew you to that?
Dr. Karen Vernau: Yeah, my kids were in middle school and they decided that we should foster kittens, which I thought would be easy, right? Because I'm a veterinarian, so I should know how to do these things. But quickly learned that there were a lot of things that were outside of what I knew, so I had to learn. So, I had to look and see what is known about, you know, upper respiratory disease and kittens and realized there wasn't a lot, you know, that people don't, there's not a lot of clinical research done on kittens, so there was a lot of anecdotes. So that just kind of pushed me to figure out, you know, how best to do things for kittens. And I think kids keep you honest.
Dr. Michael Kent: Kids keep you honest. They're going to ask you the questions, and if your answer's not there, you know, why, mom, right?
Dr. Karen Vernau: Our first round of foster kittens went to get spayed and neutered, and I'd I'd screwed up and said that one of the kittens was male when it was female. So, they've never let me forget that. But it's a, it's a learning curve, right?
Dr. Michael Kent: Yeah.
Dr. Karen Vernau: So I loved doing it and realized I didn't know a lot about it. So, I had to learn more.
Dr. Michael Kent: And like you said, there, it isn't an official specialty at this point and we don't necessarily have all the knowledge we need to tackle the particular problems of kittens. So, it was the identifying the problems and then going back and saying we had to learn more.
Dr. Karen Vernau: Yeah, it was like individual, like, what's the best way to do this? Well, there's no evidence to help me make these decisions. And then I, you know, we work at UC Davis where we have a large kitten caseload with the students, with their rescue, the orphan kitten project, and it just kind of grew from that.
Dr. Michael Kent: So why aren't kittens just small cats? Like what makes them different? Why are they not just cats?
Dr. Karen Vernau: Gosh, that is a loaded question.
Dr. Michael Kent: It is.
Dr. Karen Vernau: I mean, there's a few things. They, most of the kittens we're dealing with are born outside to feral animals. So they're not vaccinated. They're exposed to the elements. They may not have ideal, you know, nutrition. Gosh knows what they're eating, exposed to lots of infectious disease. So, they're kind of in a tough state. So that's different than what we're used to with our inside cats. I mean, they're young animals, so their immune system is not mature. So, I think there's a lot of reasons why they're different.
Dr. Michael Kent: Yeah, and then I know you're acting as faculty advisor and help with several access to care initiatives here at UC Davis, including the Orphan Kitten Project and our fracture program. Can you tell me a little bit about what the Orphan Kitten Project is and what it hopes to achieve? a little more on that.
Dr. Karen Vernau: I love the Orphan Kitten Project. So, I kind of got roped into that as being their faculty advisor, gosh, more than 10 years ago, which I didn't want to do because I felt I was too busy. But it was, it's probably one of the best things I've done as a faculty member. They're a group of students at UC Davis, so they're veterinary students who run their own nonprofit. So they're a 501C3. It was started in the 80s by Julie Levy, who's kind of a famous.
Dr. Michael Kent: Shelter vet, right?
Dr. Karen Vernau: Shelter vet now. And Florida, so she's.
Dr. Michael Kent: University of Florida.
Dr. Karen Vernau: Yeah, she started when she was a vet student and it's been going, gosh, I can't, what's my math like, more than 35 years. How's that?
Dr. Michael Kent: Fair.
Dr. Karen Vernau: So, they aim to improve the lives of kittens, but their emphasis is kittens with medical needs. So neonatal kittens and kittens that have medical issues because they're vet students. So, they foster them or they foster them one-on-one with a community member. Try and sort things out, get them healthy, fully vetted, of course, spayed and neutered, and then they go up for adoption.
Dr. Michael Kent: Great. And then how many kittens a year is OKP or the Orphan Kitten Program kind of helping each year? I know it's an incredible number, but I want to hear more about that.
Dr. Karen Vernau: It's going to vary a little bit from year to year, but it's over 600 for this year, which is a lot of kittens, especially those that have medical issues.
Dr. Michael Kent: That's huge, because those kittens otherwise would probably die.
Dr. Karen Vernau: Yeah, they take a lot from the community and our local shelters. So, they, do that. They do a lot of work with community members, like in with, children in the community and their groups working with the community. So, I think they do a lot of the work with kittens, but also with community members too.
Dr. Michael Kent: So, if a vet student takes one of these kittens in, what kind of commitment are they making to get this kitten through its earliest weeks sometimes.
Dr. Karen Vernau: Yeah, sometimes, as a newborn, it may mean that it means, 12 or 16 weeks of care, getting them through, all the early husbandry and feeding stuff, getting up every two hours to bottle feed them, through weaning period, all their vaccines and deworming, spay, neuter, microchip, all of that stuff, and then finding a good home for them.
Dr. Michael Kent: So, I know you said your kids keep you honest. And one of the things we have to do is, really, we try to do evidence-based medicine, right? And you said there's not a lot there. So, what about for husbandry? What do we know about that? Have you done research in this area? It's a leading question because I know you have. So, can you tell us what you've found about how to ideally raise a kitten, a neonatal kitten?
Dr. Karen Vernau: Yeah, we did some early work, which I'm embarrassed to say is not yet published, looking at an incubator, trying to see if, keeping them in different temperatures in the incubator would reduce the amount of feeding or volume that they needed.
Dr. Michael Kent: So not every two hours, maybe you can go to every four hours. Yeah, and maybe you could sleep through the night.
Dr. Karen Vernau: Maybe the foster could sleep through the night. Yeah, and it does, having a warm environment for them to be did make a difference in their food conversion. So that was a good.
Dr. Michael Kent: So, what's like a good temperature to keep a kitten at? Like should they just be, if you keep your house temp, like our heats often at 65, is that too cold?
Dr. Karen Vernau: 65, that is cold. Usually about 85 to 90 for neonatal kittens. They can't thermoregulate, so they they need warmth. And it doesn't have to be an incubator.
Dr. Michael Kent: Yeah, if they're neonatal, they don't have their mom there, probably. If you're taking care of them, it's because they don't have a mom.
Dr. Karen Vernau: Exactly. Yeah. Usually we're taking, you know, orphaned kittens or whatever. They're kittens without mom. So yeah, they need warmth and they can't make that.
Dr. Michael Kent: They can't cuddle up to mom and they can't make the heat themselves. So that's why they need to be so much more warm than we might keep our houses.
Dr. Karen Vernau: Right. Unless you want to carry them around on your chest underneath your jacket.
Dr. Michael Kent: I might want to do that. It might interfere with work sometimes too. So it's hard. It's a lot of commitment for anyone in the OKP project to raise these 600 cats. About how many, what percent are usually neonatal versus, you know, when they're a little bit more, you know, independent?
Dr. Karen Vernau: Yeah, I would say it's going to vary every year, depending on, you know, the fosters who sign up, you know. Neonatal kittens are hard for vet students to have because they have class and they have lab. So those take up a lot of time. But with community members, they have about 20% are, bottle babies, which may not be newborn kittens that may be, they're two weeks old. So, they may need to be fed less frequently.
Dr. Michael Kent: And when do they go to solid food?
Dr. Karen Vernau: About three-ish weeks, three to four weeks. It's a process. They don't instantly start eating magically. They've got to learn how to eat. So that is a really important time to making sure that they're eating and they're not just slurping their food and pretend eating.
Dr. Michael Kent: And I cut you off a little bit. I'm sorry. You know, because I got excited with the next question. You know, so what else have you learned about raising neonatal kittens that surprised you or otherwise we didn't know about and you found out through some of the research you've done?
Dr. Karen Vernau: You know, I think, let's see, how do I answer that? I think husbandry and nutrition are really important. And I knew that, but we can see a lot of issues with kittens, especially sick kittens when they're cold or they're just not eating enough. So I think those kind of strategies with husbandry weighing them every day, weighing them in grams, and all those things are really important for observation.
Dr. Michael Kent: And why weighing in grams? I have a pretty good idea, but why are you weighing in grams and not just popping them on your bathroom scale?
Dr. Karen Vernau: I mean, your bathroom scale could be in grams, but it's just sensitive for you or me, not something that's, you know, weighing very little. So, you've got to use an appropriate size scale so that it's sensitive enough. Yeah.
Dr. Michael Kent: So if I was 80 kilos, that's not going to work the same when you've got...
Dr. Karen Vernau: 80 grams.
Dr. Michael Kent: 80 grams.
Dr. Karen Vernau: Yeah.
Dr. Michael Kent: And so a kitchen scale would work better.
Dr. Karen Vernau: Kitchen scale, yep. And as they get bigger, we use baby scales, but the little kitchen scales with a little warm bowl. it's good so they're not going in your house. It sounds like it's a 60 degree bowl. You're going to put your kitten into that. It's like a kitten ice cube. So warm bowl.
Dr. Michael Kent: Its not that cold. I wear sweaters. So, but what else have you found? So the nutrition, the husbandry, and I know you've looked at more some specific diseases. What are some of the specific diseases that we find in cats? For kittens, I should say.
Dr. Karen Vernau: Really, we've looked at a few really common things that drive us all crazy. So upper respiratory tract infections in kittens.
Dr. Michael Kent: That's huge in kittens and cats. Why is it a bigger problem for kittens?
Dr. Karen Vernau: They, you know, they have lots of issues they're dealing with. As we talked about, poor husbandry. So, they might not, they may be cold, they may not have the immunity they might have received from their mom if she's vaccinated, and they may not have adequate nutrition and they're immature. Their immune system may be immature. So, they're predisposed to infections like herpes virus. Infection is really common. And that can make kittens really, really ill.
Dr. Michael Kent: So, what do you see in a cat like that? I know there's respiratory signs, but there's other signs as well too, right?
Dr. Karen Vernau: Yeah, they often have signs involving their eyes. So, they may have conjunctivitis, so, you know, red, itchy, watery eyes, and they may get ulcers on their corneas, which can be really painful. And they may get an eye infection in the eye, just secondary to that.
Dr. Michael Kent: Does that have long-term consequences?
Dr. Karen Vernau: It certainly can. I mean, they may lose their vision in that eye and may need to have an eye removed if they have access to a veterinarian, or they may be so sick just from the infection, they may pass away. So, if they're, it's full of pus and they're feeling sick, they may not eat. and that can be life-altering for a kitten.
Dr. Michael Kent: Yeah. And I know my center's funded some of this work, but what have you done to try to combat this ocular problem with the eyes? I know you've worked with our ophtho group some. Can you explain a little bit about the research you've done and what you've found?
Dr. Karen Vernau: Yeah.
Dr. Michael Kent: Do we have treatments for this now?
Dr. Karen Vernau: We do. We did a big study collaboratively, so with myself and the ophthalmology group and then the community surgery group, actually during COVID, which was a very interesting time.
Dr. Michael Kent: A tough time to do research.
Dr. Karen Vernau: Tough time, but important because none of the shelters were open. So, we worked together to provide, to do the study, but we also had to provide regular care for these kittens. So it was a, it's a time I won't forget, let's say that. So we looked at more than 400 kittens.
Dr. Michael Kent: That's a pretty good number, especially by veterinary study standards.
Dr. Karen Vernau: Yeah, I thought so. And was triple masked? You don't say blinded when you're dealing with an ophthalmology study. I learned that.
Dr. Michael Kent: You don't want to blind the kittens.
Dr. Karen Vernau: No, so it's a masked study.
Dr. Michael Kent: Masked study, okay.
Dr. Karen Vernau: And we looked at the involvement.
Dr. Michael Kent: Appropriate for the pandemic times. Yeah.
Dr. Karen Vernau: Absolutely. And we looked at the effect of a standard of care, which is an antibiotic named doxycycline, as well as topical eye antibiotic and an antiviral, famciclovir.
Dr. Michael Kent: So famciclovir is a drug that's actually specifically made to interact with herpes virus, right? And it's not a cat drug right off. So, you're taking, you know, something and repurposing.
Dr. Karen Vernau: Yeah, I mean, there's been some work using it in ophthalmology for, because herpes virus infection is really common, but no one has really looked at it in a population of young kittens. We were looking at kittens from birth to 12 weeks of age.
Dr. Michael Kent: Yeah.
Dr. Karen Vernau: So, and 400, 400 kittens.
Dr. Michael Kent: And then what did you find?
Dr. Karen Vernau: We found that most of the kittens did really well, whether they received famciclovir or not. And so I think that told us that husbandry is really important, but kittens that had famciclovir had a shorter time to being cured than those that did not get it.
Dr. Michael Kent: And then, something that we've been talking about also is, I'm jumping us back. Sorry, I jump around a little bit sometimes as our listeners know.
Dr. Karen Vernau: I can follow your train of thought.
Dr. Michael Kent: Husbandry. So now I. It's a term that I know and a term that you know but can you kind of explain what husbandry means? Because you're almost taking herd health terms and applying them to companion animals, to kittens, not something we usually do. Normally, husbandry, I think of cattle.
Dr. Karen Vernau: Yeah, I can see why you think that. So, husbandry, just how they're cared for. So, in this study, we trained fosters to make sure that we were, they had a warm environment, they were being fed every so often, being weighed the same way. So, they had the same kind of supportive care, I think is what you could consider it.
Dr. Michael Kent: So that's your husbandry term is what are we providing as a baseline care, you know, not medicine per se, but things in their upbringing.
Dr. Karen Vernau: Right. So ideal supportive care for these kittens. You know they weren't in a shelter, they were in a foster home being cared for as individuals or a small group. So, making sure that everybody was doing it the same thing in the same way in all groups.
Dr. Michael Kent: Okay, and then when we're thinking about this with whether we're using famciclovir in addition to the antibiotics, were there cases where the famciclovir was needed? For sure, or how do you?
Dr. Karen Vernau: I mean, it was so in this group, everybody was randomized, so we didn't make that decision. And so I can't answer that. But the group that had famciclovir had a cure rate that was faster. So, and those kittens that were removed from the study, like we had to remove some because they got worse. Those kittens were not receiving famciclovir.
Dr. Michael Kent: So, it's probably something that's helpful is what you found.
Dr. Karen Vernau: I think so. But for some, you know, because the kittens. overall did very well. If there was a situation where the, people couldn't give famciclovir, it's probably okay. But famciclovir does seem to help kittens get better faster and to have less.
Dr. Michael Kent: Which has value, right?
Dr. Karen Vernau: Especially when we're talking about, you know, as we talked about with OKP, they have 600 kittens a year. If those 600 kittens all have this condition, that's a lot of kittens to get, you know, healthy and adopted faster. So, for one kitten, maybe not a big difference, but in a in a herd…
Dr. Michael Kent: In a herd of kittens.
Dr. Karen Vernau: Or a lot of kittens, it makes a difference when we think about them that way.
Dr. Michael Kent: Yeah, So that's pretty impactful then. And, it provides evidence that this works and evidence that there's benefit, which is important. What about nutrition? So, you know, obviously you can't just open a can of cat food for them. What's best to feed them and what have you looked at?
Dr. Karen Vernau: So, we haven't looked at nutrition per se, but we've been lucky to have industry support so that we're feeding, you know, AAFCO approved kitten diets. So canned and dry food, Purina is what we have, what we fed them during the study. So, they all had an AAFCO approved diet.
Dr. Michael Kent: Yeah, in general though, what do we, that's great. And what do we, actually have, one of our episodes is, what should we feed our cat with Dr. Larson. So which people can listen to. But what about kitten nutrition in general? What do you know about that? Not in relation to this study.
Dr. Karen Vernau: Let's see. So I don't know. I'm not a nutritionist, so I don't know that I can answer that. But I think using, you know, using regular approved diets are important for kittens. kitten formula is another story in that it's not really regulated.
Dr. Michael Kent: Yeah.
Dr. Karen Vernau: So, I think you just have to, you have to choose a kitten formula that seems to work in your population. And, for us, as soon as we can wean a kitten, we try to. So, we don't keep them on formula forever. Mother's milk is best in kittens, but if it's not available,
Dr. Michael Kent: it's not available most of the time with these cases.
Dr. Karen Vernau: It's a reputable formula.
Dr. Michael Kent: Okay. And there are specific kitten formulas that you can purchase commercially.
Dr. Karen Vernau: Yep, absolutely. So, following the recommendations, making sure it doesn't sit in the fridge for 10 days, like my fridge looks like sometimes, is important.
Dr. Michael Kent: Yeah, obviously if the food's gone bad, if their main source of nutrition's got bad, you could injure the kitten.
Dr. Karen Vernau: Absolutely, make them really sick. So yeah.
Dr. Michael Kent: So, I know you've also been looking at hypothyroidism in kitten. kittens. Why is this important in kittens as maybe opposed to cats or does it have more effects on them?
Dr. Karen Vernau: Yeah, I mean, I think one of the pluses about looking at in that famcyclovir study that CCAH funded, we looked at so many kittens as the primary source. You see other things come out, you know, and as we're looking at kittens' growth in that study with it being a weight every day, we noticed that some kittens weren't growing. So that was just something that came about because we wondered what was happening with them. Why weren't they growing? Did they have a liver or kidney or thyroid problem? So, I think it's, in our literature, it's reported in kittens six weeks of age and older, yet it's a condition that they're born with. I think it's just been under-recognized because we aren't, in our profession, we're not looking at a bunch of kittens that little and looking at them that carefully. And when you do, you see it. Like it's...
Dr. Michael Kent: So if a cat is hypothyroid, could you explain it to me? What is going to be the effect on them long-term and particularly for a kitten?
Dr. Karen Vernau: Yeah, right, in a kitten, sometimes they pass away because their thyroid hormone is needed for every single cell in your body to grow. And they can be... really get into trouble. So those that live, they're very small and unfortunately they're really cute looking. But they look like young kittens. They have blue eyes, their ears are bent down, they have short, stocky legs, and they can have trouble with constipation. And they're mentally dull. You know, they're not bright and alert and playing. And…
Dr. Michael Kent: So they don't grow and thrive if they don't have enough thyroid hormone. Exactly. So they're hypo, meaning too little thyroid hormone.
Dr. Karen Vernau: Yep, and I think a lot of the little guys pass away before we recognize it.
Dr. Michael Kent: So, what are you doing to answer more questions about this or find out what the effect of treating it is? I mean, where are we going with this now that you've identified this problem by looking at a large number of cats and weighing them daily? Good husbandry.
Dr. Karen Vernau: The first thing we had to do is look at what is normal thyroid. Like we have normal, what is a normal T4 in a kitten?
Dr. Michael Kent: And the T4 measuring…
Dr. Karen Vernau: Just the baseline thyroid hormone and then some of the central thyroid stimulating hormone, the TSH. So. we didn't have normals for kittens. And it may be that, you know, a cat isn't growing, so it may have different levels than a kitten.
Dr. Michael Kent: What'd you find?
Dr. Karen Vernau: Yep. Surprise. Kittens have a higher basal thyroid hormone. So we needed to know that.
Dr. Michael Kent: Because they need to grow.
Dr. Karen Vernau: They're growing. So, we had to figure that out that first. So that took a little bit to figure out what was normal in kittens of certain ages. So, thank you for that. And then just trying to figure out what, you know, what formulation and what dose of the thyroid hormone do we give kittens? And what, Kittens need a much higher dose of of the hormone, which is called levothyroxine or T4 to give them than, dogs or adult cats do.
Dr. Michael Kent: Interesting. And so have you kind of, your goal is to then obviously publish this stuff so other people can take that information, right? I mean, this is still pretty new.
Dr. Karen Vernau: Yes
Dr. Michael Kent: Is it published yet?
Dr. Karen Vernau: Not published. You sound like the rest of my crew. It's, the manuscript is in the works.
Dr. Michael Kent: Excellent. But this is important information. So, it's groundbreaking information basically in order to make sure that these kittens who are a hypothyroid. How common a problem is this? Did you find?
Dr. Karen Vernau: Yeah, I don't know how common it is, but in our group we have 33 kittens.
Dr. Michael Kent: 33 of 400.
Dr. Karen Vernau: And not in our study group, but we noticed it during the study. So that was in 2020.
Dr. Michael Kent: Yes.
Dr. Karen Vernau: And since that time, we have diagnosed and treated 33 kittens.
Dr. Michael Kent: So, still fairly substantial. It's not 10% of the population by any means,
Dr. Karen Vernau: Nope.
Dr. Michael Kent: but it's still enough that this really affects not only the kittens, but even the people who are raising them if they they're not thriving, that's obviously really hard on the kitten raisers too.
Dr. Karen Vernau: Right. It's like a dream where you can diagnose a condition and give them a pill and treat them. You know, there's some things we have to do. They're growing, so you've got to increase their dose as they're growing. And then there's some things to note as they get older. But yeah, it's, I love it. It's just, it is a dream in veterinary medicine.
Dr. Michael Kent: So, what else have you been looking at or what else are you trying to figure out in kittens like that you see as these particular problems that face kittens?
Dr. Karen Vernau: There's so many things, Michael. It's like my desk is littered with things that I want to figure out. One of the things we noticed.
Dr. Michael Kent: Like me with cancer questions.
Dr. Karen Vernau: Right? Yeah. In the, you know, in the famcyclovir study, we noticed that some kittens had a condition called eyelid agenesis, where their eyelids don't form normally. And in the past, our ophthalmology group has had to do a big reconstructive surgery, which is okay for some kittens and some owners, but maybe out of reach for…
Dr. Michael Kent: It’s expensive,
Dr. Karen Vernau: Very expensive, and some of them they needed revision.
Dr. Michael Kent: So to repeat the surgery.
Dr. Karen Vernau: Repeat the surgery or, you know, maybe have their eye removed, which is not also accessible for everybody, or worst case, be euthanized because they have a painful ocular condition. So, one of the ophthalmologists, Dr. Charnock, does some work with laser treatment. And that's something we're looking at right now is to do a little bit of surgery and some laser on the eyelids.
Dr. Michael Kent: So laser to remove part of the eyelid or stimulate growth. What is it?
Dr. Karen Vernau: Yeah, stimulate healing once it's been removed so that the, you know, the eye is a normal shape and the eye, the eyelashes aren't, you know, digging into the cornea, which hurts.
Dr. Michael Kent: Yeah, so the surface of the eye.
Dr. Karen Vernau: Yeah, surface of the eye, exactly. So that's something we're looking at. as a non-invasive way to treat these guys and save their eyes and vision and their lives potentially.
Dr. Michael Kent: So, it's something you notice and something they're trying and it looks promising. So now you take it to a clinical trial to actually prove it.
Dr. Karen Vernau: Exactly, Yep.
Dr. Michael Kent: Excellent. And what else? Anything else there?
Dr. Karen Vernau: So many other things. You know, wondering about the genetics of eyelidogenesis. We notice it in some other wild cats like snow leopards. So trying to look at, you know, we noticed that Some of these kittens with eyelid agenesis when they're male, they may have a retained testicle. So, wondering about the connection there. And if we can figure out the genetics of that in snow leopards, you know, maybe it's something that we can help both populations moving forward.
Dr. Michael Kent: That's cool. So almost our kittens could be a model for some larger endangered cats.
Dr. Karen Vernau: Potentially, and just working, you know, trying to work collaboratively and together. You know, I'm a clinician, so I'm not doing bench type research, but we can be pretty helpful when we all work together on a problem, bringing something different to the table.
Dr. Michael Kent: So, I know you've recently been involved with the start of a pediatric fellowship here that's been started. And can you tell me why that's important? And do you think we need pediatric medicine to be a new veterinary specialty?
Dr. Karen Vernau: I mean, I do.
Dr. Michael Kent: Softball question, I know.
Dr. Karen Vernau: I’m slightly biased about that.
Dr. Michael Kent: Of course you're biased about it because you're passionate about it. So no, but why is it important and do we need it?
Dr. Karen Vernau: I think we do need it. We need people who are expert in dealing, you know, dealing with day-to-day stuff, taking blood on a kitten. How do we feed them? How do we manage them? And trying to look at their, how do we do better for them with their medical and surgical needs and their outcome? And I think it can help cats, you know, kittens become cats and other, you know, maybe it helps puppies and we have a project on the go with the medical school, and we're working together to help kittens and babies. So that's really cool too.
Dr. Michael Kent: Looking at what?
Dr. Karen Vernau: Looking at kittens with hydrocephalus and obstructive hydrocephalus. So we're...
Dr. Michael Kent: Can you explain what hydrocephalus is? Yeah.
Dr. Karen Vernau: So they've got too much water on their brain, and if it's obstructive, the water's not moving out from their brain.
Dr. Michael Kent: So it doesn't allow normal brain tissue because it's fluid there instead and it's against the skull.
Dr. Karen Vernau: Exactly. So, it's putting pressure on the brain. And so in the past, those kittens, at least in my hands, have all passed away. But this is an exciting treatment to kind of shunt the fluid from from being basically in a traffic jam to go around the traffic jam so they don't need to have like a shunt from their brain into their abdomen.
Dr. Michael Kent: So basically, it will help remove it from the brain and make it more normal and allow the brain to develop.
Dr. Karen Vernau: Yep and save their life if it works. And maybe for humans, for human pediatric neurosurgeons, a kitten's pretty darn small and sometimes they struggle doing these kinds of procedures on small babies. So, helping make it ideal for a kitten may help apply it to a baby.
Dr. Michael Kent: Yeah, that's pretty cool. So, what would you tell, what advice would you give to someone new who wanted to foster a kitten or someone who found or adopted a kitten? What would be the take-home message for them?
Dr. Karen Vernau: So, for a new foster, I would hope that they'd be working with a rescue group, like the students with the Orphan Kitten Project, where they have a lot of support in trying to make sure things are optimized for their kitten.
Dr. Michael Kent: So, all the husbandry things we talked about.
Dr. Karen Vernau: Husbandry is really, really important. And you know, the students are great mentors for each other and trying to work through that and then they have faculty mentorship as well. But fostering is great because you get mentored through that whole process.
Dr. Michael Kent: Yeah. And I know you have a website for the OKP project and the like, or at least some links, right, for information availability.
Dr. Karen Vernau: I think they do have a website, yes.
Dr. Michael Kent: So, I think what we'll do, if it's okay with you, is we'll post that with the podcast episode if people are interested in finding out more.
Dr. Karen Vernau: Yeah, that sounds great.
Dr. Michael Kent: So, is there anything I should have asked you that I didn't yet or anything you want to ask me? Yeah.
Dr. Karen Vernau: I don't think so, but I think, for a long time we've done research on clinical research in dogs and cats have kind of, lost out on some of that.
Dr. Michael Kent: Why?
Dr. Karen Vernau: I don't know why, but I think, kittens, kittens need some clinical research to be done. So we know how best to do things. I think time is coming for kittens. We're going to be in that realm.
Dr. Michael Kent: And with that, time is coming for kittens. So, I really wanted to thank you, Dr. Vernau, for joining me today and talking about kittens, all we need to know. And I so greatly appreciate it. Thank you.
Dr. Karen Vernau: Thanks for having me.
Dr. Michael Kent: Of course.
The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe Unti. Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E10: First Aid
- Read the Transcript
- Dr. Jamie Burkitt: Our recommendations, of course, as always, are for safety for the rescuer first. And then, yeah, there is no doubt that tourniquets save lives. 100%, they do.
Dr. Michael Kent: Hello, and welcome to today's episode of The Vetrospective, a podcast designed for animal lovers, advocates, and caregivers. This is your host, Dr. Michael Kent, coming to you from the UC Davis School of Veterinary Medicine. First aid is medical attention given right after an injury or accident before being seen by medical professionals. It could be life-saving, and while we usually think of this as for people, it is really important for pets as well. Emergencies for dogs and cats where owners can help stabilize their pets on the way to the hospital can range from trauma causing severe bleeding to respiratory distress and heat stroke amongst others. But what works and what doesn't? Does delaying time to get to a veterinary hospital for providing this care help or hinder your pet's treatment and recovery? What practical things can we do in an emergency? These are the issues we will talk to you about today.
So, joining me is Dr. Jamie Burkitt. She is a professor of clinical small animal emergency critical care at UC Davis. She became board certified in emergency and critical care in 2005 and since then has practiced across the United States in both universities and private emergency and specialty hospital settings, until really coming here back in 2017 and setting down her roots. She serves as the guidelines co-chair for the RECOVER Initiative, which is an educational initiative that develops evidence-based consensus guidelines for life-saving measures in dogs and cats. Her area of interest include cardiopulmonary resuscitation, I can say that, prevention of recurrent feline urethral obstruction, and endocrine-related emergencies. So welcome to The Vetrospective, Dr. Burkitt, and thank you for joining me today.
Dr. Jamie Burkitt: Thank you so much, Dr. Kent, for that introduction, and thanks so much for having me today.
Dr. Michael Kent: Oh, no, this is so important. So, this first question is something I ask everyone. So why did you pursue a career in veterinary medicine?
Dr. Jamie Burkitt: Oh, that's a great question. Coming out of high school, going into college, I knew that I did, I was not probably prepared to spend my career sitting at a desk. And I was pretty strong in math and science. And so I actually went to undergrad planning to go to medical school. We'd always grown up with animals in the house though, and absolutely loved animals. And I had worked in a veterinary hospital a little bit here and there in high school. And then when I went to college and volunteered in some of the human emergency room settings and surgical ward settings and things like that, I realized that human medicine probably wasn't for me.
Dr. Michael Kent: Fair.
Dr. Jamie Burkitt: Yeah and sort of had a bit of a crisis and thought, my gosh, what am I going to do with myself? I've taken all these pre-med classes. I have, studied science and math and this has been my path the whole time. What am I going to do? And kind of search back to my roots and realized how much I really could apply that same, those same principles and all of that background to veterinary medicine and how much I loved animals and thought that would be a good path for me. So, here I am.
Dr. Michael Kent: Very cool. But then emergency and critical care, what drew you to this specialty area in veterinary medicine?
Dr. Jamie Burkitt: Oh, that's a great question too. So, I think the thing that drove me the most to emergency and critical care on a principal standpoint is that I really struggled to give up the practice of anything. So, I couldn't imagine my life, not doing any cardiology, not doing any diagnostic imaging, not doing any internal medicine, not doing any surgery or procedures, knew that I really wanted to be able to do all of those things. And when you're an emergency clinician or a criticalist, these are two kind of different hats that the ECC specialist wears in veterinary medicine. You really still get to do all of those things, a little bit of all of those things. So, I think that's why I really love it and what drew me to it. And originally I thought I might want to pursue something else, but the truth is when I came out of veterinary school, I realized the only jobs I was looking for were emergency jobs. That sort of spoke to me to realize, actually, you're really only trying to work in this space. Maybe that's what you love and was a bit of a wake up call for me. So shortly thereafter, I pursued residency training.
Dr. Michael Kent: This is great because I love hearing everyone has a different path and a different story. And that's why, you know, I asked this question first once and then I was like, oh, that's cool. So thank you for sharing that. And Kind of getting into what we wanted to talk about today, I'm really interested in the RECOVER initiative and want to talk to you more about this. You know, I believe it was initially formed to come up with guidelines for CPR or cardiopulmonary resuscitation for dogs and cats. How did you become involved in this and can you explain a little bit about the RECOVER initiative?
Dr. Jamie Burkitt: Yeah, absolutely. Thank you for this question because RECOVER has definitely become one of my main passions.
Dr. Michael Kent: That's why I asked you to talk about it today.
Dr. Jamie Burkitt: Yeah, absolutely. So yeah, the RECOVER Initiative is this really amazing educational initiative. And our main mission really is to empower people, and not just veterinary professionals, but people, to be able to provide life-saving care to animals. And we kind of want to be able to do that through education and science, so evidence-based from science and community. I got involved in the RECOVER Initiative, which is now a non-profit organization, basically. I got involved in the RECOVER Initiative in, we think we can trace it back to the end of 2018, maybe. It's one of those things where they, some colleagues of mine, Dan Fletcher, Manu Boller, asked me, hey, we, you know, we had come out with these guidelines back in 2012, and now we're looking to update our CPR guidelines, and we're hoping to bring in some help. It's a huge endeavor, would you be interested kind of thing. And I joined them, we think sometime around 2018 and started working on the updated CPR guidelines for dogs and cats, which came out in 2024 with the pandemic in the middle. It took quite a while for us to get those out. But basically has become a growing initiative. Basically, we now have, we're forming a board as a new nonprofit, and we're really excited about this. however, is our first expansion out of the CPR space and into first aid. On the human side, there of course are, I think most people are probably familiar with, the American Heart Association here in the United States has guidelines that they promote and then teach in person for bystanders to be able to perform CPR in people. And then also, of course, they have a first aid kind of domain or section as well. And in that first aid domain, you can go to courses, of course, to learn how to provide first aid to other people who you may find in the community who are, you know, you're out hiking and someone gets hurt or something like that. And so similarly, RECOVER decided for our update in the 2020s that we were going to also start a first aid domain. And so it's on the precipice of publication now. So really excited about that. But this is our first dive, even though the initiative is now about 13 or 14 years old. This is our first dive into the first aid space.
Dr. Michael Kent: That's pretty exciting. Can I wheel you back just a little bit and talk a little bit about RECOVER CPR?
Dr. Jamie Burkitt: Oh yeah.
Dr. Michael Kent: Because I know for, so I'm, obviously you know this, but I'm a clinical veterinarian, I'm a radiation oncologist. And I anesthetize a lot of patients along with my technical staff. And we also felt it's really important, even though I'm not a criticalist, we are going to be the first people on the scene if one of my patients under anesthesia has problems. So we've done, as a team, we've done a little course to update us on CPR and keep us refreshed because fortunately this is not something I have to do very often. And while we immediately call for help, it takes a few minutes for someone to get to us. So we need to start. So these guidelines, I think, are essential for veterinarians, but they're also for laypeople, right, who have pets. And so can you talk a little bit about that, why that's important?
Dr. Jamie Burkitt: Yeah, sure. So kind of to touch on the exact scenario you're talking about, the interesting thing is that the best outcomes possible from CPR which of course CPR is something we do when an animal's heart stops beating and they stop breathing, which is a very critical moment of life. If something is not done immediately, that animal is going to die. So you're speaking exactly to the purpose of RECOVER, which is that the patients that have the best possibility of going home with a good outcome, doing great, quote unquote, back to themselves, are animals that are relatively healthy. I recognize you're anesthetizing cancer patients, but many times these animals are systemically quite well.
Dr. Michael Kent: Exactly. Most of the times my patient has cancer and otherwise is healthy. It might be elderly, but age is not a disease.
Dr. Jamie Burkitt: age is not a disease.
Dr. Michael Kent: You've heard me say that before.
Dr. Jamie Burkitt: Oh, we've all said it.
Dr. Michael Kent: Yes.
Dr. Jamie Burkitt: Oh, we all believe it. So basically, really, those animals that are systemically well do not have a terminal disease process, but especially those undergoing an anesthetic event, that could be for your radiation treatment. It could also be a spay or a neuter in a clinic. Those patients are in this really interesting subset that are the most likely to be successfully resuscitated if their heart stops beating or they stop breathing and they're the most likely to be able to go home and have a really good quality of life afterward. And sort of the, I don't know, it's a bit of an unfortunate intersection is that... It is so, it's great that it's so incredibly uncommon that we find these life-threatening events under anesthesia. That's great. It hardly ever happens.
Dr. Michael Kent: Yes, incredibly rare.
Dr. Jamie Burkitt: But what that also means is that the veterinarians and the veterinary staff who are encountering these animals, who are basically systemically well, who are undergoing anesthesia for what could be a fairly routine procedure, especially to the person, you know, going through this procedure, maybe not for the pet, but for the veterinarian and the veterinary staff, this is routine. They're hardly ever in the space where they need to be able to do CPR. They haven't done CPR in 6 or 12 months because it happens so infrequently.
Dr. Michael Kent: Or several years in my case.
Dr. Jamie Burkitt: Or several years. So then if an animal arrests or, you know, stops breathing, their heart stops beating under that anesthesia, this is also the team that is the least accustomed to having to perform CPR.
Dr. Michael Kent: Exactly.
Dr. Jamie Burkitt: So, the goal of the RECOVER initiative is to empower teams of veterinary professionals. And really when we get to the at-home space, even owners of pets, groomers, people who are dog walkers, people who are pet sitters, and of course also our first responders who work with canine officers for empowering all of these people to be able to provide high quality evidence and consensus-based care to animals in their times of need. So, we as an initiative have online coursework as well as provide in-person hands-on training, just like the American Heart Association does.
Dr. Michael Kent: So, if it's okay with you, we're going to post the website information where people can get more information and sign up for these type of online courses, because those are for lay people as well, right?
Dr. Jamie Burkitt: Yeah, we absolutely have a, we have a lay person, pet, what we call pet owner.
Dr. Michael Kent: Yeah.
Dr. Jamie Burkitt: But really it's, it is for pet owners, but also it would be appropriate for the kind of paraprofessional. So for a groomers, dog walkers, pet sitters, et cetera. And, people who own pets who have chronic illnesses, like I have two elderly cats that have to be medicated every day, things like that, because I'm a, just like being a vet, I'm also a pet owner. I have to be really careful who I ask to come watch my animals because they need to be prepared for there to be,
Dr. Michael Kent: An emergency.
Dr. Jamie Burkitt: An emergency, yeah, something wrong with one of my animals at home. So as an owner of pets, I really want to have people helping me with my pet sitting or whatever that have some of these skills.
Dr. Michael Kent: Now you said something interesting to me too. You needed evidence-based, consensus-based guidelines. So why do we need guidelines and how do you go about validating them? I assume this is why it took from 2018 to 2024 to come up with these first CPR guidelines.
Dr. Jamie Burkitt: Yeah, that's a great question. It's, you know, this is a double-edged sword, evidence and consensus-based. So, we think that it's really important to have evidence, the best evidence we could have would be large-scale evidence available in the species in question. So dogs, cats, foals, rabbits, you know, all of these different companion animals. At this stage, we have almost no evidence in these species to inform what we should do in these emergency situations. There is some. A lot of it actually comes out of laboratory experimental space, but we have more and more in the clinical space. But almost all the evidence that we find available is from the human space, the human clinical trials area.
Dr. Michael Kent: So ,we're using humans as the guinea pigs in a sense, right? And taking it back to our patients.
Dr. Jamie Burkitt: Yeah, that's exactly right. So, what we did was we used a a process called the grade evaluation technique and scores really hundreds of veterinary professionals, both veterinarians as well as veterinary nurse technicians, to review the evidence and to rate it, for instance, for any risk of bias of that evidence. How directly do we think these findings apply to dogs and cats, or if we're talking about the large animal guidelines, foals, things along those lines, how directly do we think they apply? Kind of synthesize all that and come up specifically with veterinary recommendations based on the information, which again, we considered, of course, the human evidence, because that's what there mostly is. But where veterinary and animal experimental evidence was available, we also used that.
Dr. Michael Kent: So it's a starting point that you can use.
Dr. Jamie Burkitt: Yeah
Dr. Michael Kent: And then you can actually, from there, gather data and actually validate it in a sense. So take the consensus and make it more evidence-based, which is what we try to do, right?
Dr. Jamie Burkitt: Yeah, and I think we really used the evidence that we found. synthesized it as a group of kind of subject matter experts, how does this apply, wrote treatment recommendations for dogs and cats, and then we released them for international consensus for a month in the summer of 2023, basically for the CPR guidelines. And during that month, we got feedback from around the world about the treatment recommendations that we were making. We then went back as a committee, an executive committee and domain chairs, and altered our treatment recommendations based on the reality of what the people on the ground were recommending and saying we should do, making sure that still was aligned well with the evidence that was available, and then had all of those published in the summer of 2024 as pertains to the CPR guidelines.
Dr. Michael Kent: So I know, I mean, I know that for my team, this has been important because basically what I was taught in vet school a long time ago was different from what I learned when we ran our practice drills. And it was also a good refresher. So are you collecting information on how how well this is being disseminated and who this is reaching. Are you're trying to get that kind of information as well as part of the RECOVER initiative?
Dr. Jamie Burkitt: Yeah, that's a great question. Absolutely, because we definitely want to know our, does it matter is what we say matters. Is it helping? And then also to part of our process is also to generate new evidence, of course, but also to recognize knowledge gaps or critical gaps in knowledge that need to be explored. So, what we've done is pose a bunch of knowledge gaps in our guidelines and in our domain papers that we hope investigators will look into. And then from the research side, Dr. Manu Boller is the co-chair that is in charge of our research and registry pillar. And there is a registry where a variety of different veterinary hospitals, small animal hospitals at this time, from around the world provide CPR incident information into a registry, and we have thousands of cases at this point that have undergone CPR. And then researchers, basically, in the veterinary space apply to use that information from the registry and produce papers or publish papers. Regarding CPR, how is it going? Are there changes in practice compared to what used to be before the guidelines came out, et cetera?
Dr. Michael Kent: And what's most effective?
Dr. Jamie Burkitt: And what's actually working, yeah.
Dr. Michael Kent: So, this is a pretty big deal.
Dr. Jamie Burkitt: Yeah, we're proud of it. And we, yeah, we're still growing. So we also hope, we hope that what we're doing is helpful. That's our goal.
Dr. Michael Kent: Yeah, of course. So I'm going to. What I told you I was going to ask you about, and of course I go down rabbit holes all the time, but I was going to ask you about the upcoming first aid guidelines a little bit for dogs and cats. So why did you decide to tackle it next? Was it just the next big hole that you saw or, you know, what led you down this path?
Dr. Jamie Burkitt: That's a great question. So we are interested in helping people, empowering people and teams to help animals, using this evidence and consensus-based process, and so we know that... all of us as pet owners, people who are paraprofessionals or professionals outside the veterinary space, like first responders who have, canine officers with them…
Dr. Michael Kent: Really important.
Dr. Jamie Burkitt: That all of these individuals need to be able to help their pets in the best or canine companions as it were, canine officers in the best, most evidence-based way possible. And there really were no guidelines out there, which means that, you know, if my neighbor had a problem with their dog. For instance, say their dog stepped directly into a caustic substance in the kitchen that they were cleaning the kitchen floor with, and their dog has a chemical burn on its paw pad, you know, what are they supposed to do? And the truth of the matter is that for many of these interventions and many of the questions we're asking in the first aid space, first of all, a lot of them are based on the human first aid questions and the human first aid, you know, guidelines.
Dr. Michael Kent: Again, a starting point, right?
Dr. Jamie Burkitt: Exactly. Many of them are absolutely what you could do for an animal in that first 10 to 15 minutes. In other words, another way of saying that is before you can get to the vet hospital, before you could possibly get there, is absolutely life-changing and sometimes life-saving what you could be able to do for them. So, we felt like it was really important to provide people with this guidance as well. And I'm so excited to have worked on this domain. It's a really, really fun domain.
Dr. Michael Kent: It's cool. And it's really broad applicability.
Dr. Jamie Burkitt: And it's really broad applicability. That's exactly right. Like super broad applicability.
Dr. Michael Kent: So, if you'll give us the website links, we will put them on our website so people can go to it because I assume it's going to be on the RECOVER website as this builds out and it's released.
Dr. Jamie Burkitt: Yeah, absolutely. We should be available, we hope, before the end of the second quarter published, yeah.
Dr. Michael Kent: So you were talking a little bit about a dog or cat coming into the kitchen, stepping in something caustic. So how do you think about this? So what kind of things do dogs and cats usually get covered in, first of all? So what different types of toxins do we think about? when doing this.
Dr. Jamie Burkitt: Certainly I think the most common that I'm aware of, although we didn't actually look into this evidence wise, but that I'm aware of would be the example that I gave you as far as a caustic substance would be stepping in something that is caustic, for instance, bleach or some other type of cleaning solution. I personally have managed dogs that, you know, were owned by people who also owned restaurants. And they would walk through the kitchen as they had cleaned the floor of the restaurant at the end of their day at the end of their shift and burned all four paw pads.
Dr. Michael Kent: Paw pads
Dr. Jamie Burkitt: Exactly. It's, just can be really actually life ending, sometimes, because it certainly causes such significant burns on their feet, or could do, that it requires weeks of surgical management and in-hospital management and things like that that's frankly super painful for the dog and also can be cost prohibitive for the owner.
Dr. Michael Kent: So, Dr. Burkett, my dogs just walked through the kitchen and we've just put something really nasty on our kitchen floor. Do I wash their paws? Do I irrigate it with water? Should I use soap? Like, how long do I rinse the area? What do I do?
Dr. Jamie Burkitt: That's a great question. So, we are leading in every situation with no, just like they do on the human side, no risk to the rescuer. So, we are first and foremost, an owner or caregiver of an animal has to think about their own safety. So, we would only encourage doing things where the animal seems amenable And so….
Dr. Michael Kent: You don't want to get bit.
Dr. Jamie Burkitt: Yeah. And it, even our animals who love us, we care for them. They might, let's be honest, I have a cat that sleeps on the pillow next to my head every single night.
Dr. Michael Kent: Mine often sleeps on me.
Dr. Jamie Burkitt: So, we we're all very close to our animals. They do love us and we love them. And when they are in pain, they really have, or scared, or both, they only have a couple of ways that they can react and biting even their pet parents is a totally natural reaction. So, I think none of us should believe that our animal would never bite us because sometimes they might.
Dr. Michael Kent: So this is any of emergency situations.
Dr. Jamie Burkitt: So we have to be really careful. Yeah. So first and foremost, we watch out for our human selves. We don't want to end up in the emergency room too. But the answer to your question, after ensuring that we are safe for ourselves is that we think that the best recommendation for caustic substance exposure is running water. So running water, truly a hose, one of your sink attachments that kind of comes off and acts like a hose,
Dr. Michael Kent: Sprays.
Dr. Jamie Burkitt: Exactly, for 15 minutes over that area. So really, really important. Dousing or holding in water is probably not enough. Really that running over is important because it's constantly clearing away whatever that toxin may be.
Dr. Michael Kent: So now I've rinsed them as best I can and I'm on my way to the vet. What if they lick at it? Or should I try to stop them from doing that?
Dr. Jamie Burkitt: That's a great question. I think the best you can do is to hope that they don't lick at it. Again, you yourself should be, if you have at home latex gloves or non-latex vinyl type gloves or something like that at home, even when you pursue this attempt to rinse their feet, again, you're watching out for your own well-being.
Dr. Michael Kent: Oh yeah, wear gloves.
Dr. Jamie Burkitt: Obviously, you're gonna wear gloves if you have those available to you, even dishwashing gloves, anything like that. And then ideally, if you are to keep them from licking themselves, that would be great. But if you've done the 15 minutes, chances are you're probably in decent shape there. As much as possible, yeah, it would be ideal if they not then lick that area.
Dr. Michael Kent: So maybe if you had an E-collar at home from a previous... you could pop that on.
Dr. Jamie Burkitt: Yeah. That would be perfect.
Dr. Michael Kent: I'm just trying to think of things like, I'm wondering if we should almost come up or if you haven't thought of this, like an emergency kit to have for your dog at home.
Dr. Jamie Burkitt: Yeah, that's kind of in our list that will likely appear in these guidelines. Yeah.
Dr. Michael Kent: So, we were just talking about a toxic substance, but I think probably more common is like your dog eats something. They eat, because they eat something they shouldn't eat. This could be rat poison, snail bait, antifreeze, prescription medications for you or them, or foods that can be toxic to pets, like let's say grapes or chocolate.
Dr. Jamie Burkitt: Yeah.
Dr. Michael Kent: And so, what should an owner do if they see their dog or cat eating one of these things? Besides making them stop if you can.
Dr. Jamie Burkitt: Yes, exactly. Remove if possible.
Dr. Michael Kent: Yes, remove so they don't get more because everything's dose dependent, right?
Dr. Jamie Burkitt: Pretty much. We think so. Most things are anyway.
Dr. Michael Kent: You want evidence?
Dr. Jamie Burkitt: Most things are. Some things are what we call idiosyncratic, so may not actually be as dose dependent, but it is possible.
Dr. Michael Kent: Like grapes…
Dr. Jamie Burkitt: That probably is dose dependent, interestingly, but different dogs seem to need different doses.
Dr. Michael Kent: And idiosyncratic means it can happen and like just.
Dr. Jamie Burkitt: Tiny amounts.
Dr. Michael Kent: Tiny amounts, but not every case.
Dr. Jamie Burkitt: Most not cases, right? Exactly. So it's hit or miss as it were. But for the most part, I completely agree with you. Doses really do matter. You
know, it's interesting that this is the one we are talking about in that ,the human, on the human side, this is answered. You really should not induce emesis at home.
Dr. Michael Kent: Emesis, meaning don’t make them vomit.
Dr. Jamie Burkitt: Vomiting, right, that's right. On the human side, this was actually some of the largest studies we found. One study we found was from a human poison control center that included almost or just over 750,000 calls to poison control. And they included outcomes for did the individual need to go to the hospital and also did the individual die or not die? Almost a million people.
Dr. Michael Kent: Important outcome point.
Dr. Jamie Burkitt: Yeah, really important, two important outcome points. And the answer was that it made no difference if you induced vomiting at home or not.
Dr. Michael Kent: I've heard use ipecac or hydrogen peroxide. And I know there's dangers for that too, right?
Dr. Jamie Burkitt: Both of these things actually have the considerable risk to dogs and cats at home. So, this is not without risk to try. And there is not strong evidence. And one might actually argue that there is evidence that it is not helpful. So, I will say though, and I feel like…
Dr. Michael Kent: This is counterintuitive.
Dr. Jamie Burkitt: I understand, I get it.
Dr. Michael Kent: No, that's why I want you to talk more. That's why you're here.
Dr. Jamie Burkitt: Well, it also is not agreed upon in the veterinary space yet. So, in other words, we've found this information. We found smaller studies in like children that eat the red berries off of plants at home.
Dr. Jamie Burkitt: We found overdoses of acetaminophen in particular. This is a big, big one.
Dr. Michael Kent: So, Tylenol, or the brand name, of acetaminophen.
Dr. Jamie Burkitt: or paracetamol, depending on where our clients are living.
Dr. Michael Kent: Yes, yes in the UK
Dr. Jamie Burkitt: Exactly. But the, You know the evidence in these cases in human beings is that home vomiting does not help. It does not matter. Now, that doesn't mean they don't need to see a medical professional. Animals that eat things they should not eat should see a veterinarian.
Dr. Michael Kent: You see a dog eating blue stuff in your backyard or your neighbor's yard.
Dr. Jamie Burkitt: As soon as possible.
Dr. Michael Kent: That's rat poisoning, probably right.
Dr. Jamie Burkitt: As soon as possible, yeah. It depends on the blue thing, but yeah.
Dr. Michael Kent: Blue is bad,
Dr. Jamie Burkitt: Blue is bad, green is bad.
Dr. Michael Kent: So I know there's a poison control hotline for animals too. Is this something that they should be calling on the way to the vet? Is this, and maybe we should, we'll put their numbers in if you could provide those to me as well. We'll put them on the website also.
Dr. Jamie Burkitt: That's a great question. So I think it depends a little bit. If you live 10 minutes from a veterinary hospital that is open at the time of the problem, you're probably just as good to take your animal to that veterinary hospital as soon as possible. If it's eaten something that you are concerned about, period, whether you know it's toxic or not, or maybe you just saw them swallow a piece of a tennis ball. I mean, it could also be that, right? Which isn't toxic,
Dr. Michael Kent: An obstruction.
Dr. Jamie Burkitt: but blocks the way.
Dr. Michael Kent: It could kill them.
Dr. Jamie Burkitt: Exactly. And so many of these cases, once they reach the veterinarian, the answer to the vomiting question is different. So, the downside is that for home vomiting is that both things we have available to us for inducing vomiting at home pose really significant dangers to dogs and cats. That's syrup ipecac and hydrogen peroxide, both quite dangerous for dogs and cats at home. I think our recommendation is going to be not to do it. But again, this hasn't been through consensus process, and there is a lot of disagreement on this, even among subject matter experts.
Dr. Michael Kent: So, this is something that we need to learn more about.
Dr. Jamie Burkitt: We need to learn more.
Dr. Michael Kent: But we do know that probably if they get to the veterinary hospital, we are going to induce vomiting with a safer drug.
Dr. Jamie Burkitt: With a safer drug. That's exactly right.
Dr. Michael Kent: And then we're probably going to try to absorb whatever toxin is if we have, let's say, activated charcoal or something like that. And if not, or if it's been too long, we'll dialyze them, right, and pull it out of their blood. because toxins are not good. Great. I appreciate that. That's so calling the poison control center while you're getting there, but not if it's going to delay you getting there.
Dr. Jamie Burkitt: Yeah, exactly and I also think it's a different story if you are camping. and your dog eats something and you're 2 hours away from anyone, but you can get a cell signal, call Animal Poison Control. That's the answer. And then do what they say. Or call the vet that you normally use and see what they say. They may make a recommendation if they're open, you know, may make a recommendation to you. Oh, you don't need to worry about that one specific thing you just saw your dog eat.
Dr. Michael Kent: You just ate a small bit of milk chocolate and the weight of your dog, your dog's not going to seizure.
Dr. Jamie Burkitt: Don't worry about it.
Dr. Michael Kent: Don't make them vomit and risk getting pneumonia from aspiration.
Dr. Jamie Burkitt: Exactly. Yeah.
Dr. Michael Kent: Thank you. That's cool. So I guess another emergency I think of is bleeding. You know, let's say dog's got a big laceration or something. And I know the basics is apply pressure.
Dr. Jamie Burkitt: Pressure.
Dr. Michael Kent: But it's severe. Can you put a tourniquet on? Like, where can you do this on a pet? Like, what should we use? A belt? how tight should you apply it and how long can you keep it on?
Dr. Jamie Burkitt: So we answered some of this for our investigation for first aid and RECOVER. Some of that we've addressed. The yes, no, is it worthwhile putting on a tourniquet if you have an extremity? So tourniquets only work on extremities, and that's basically in dogs and cats, that's limbs and tails.
Dr. Michael Kent: Legs and tails, okay.
Dr. Jamie Burkitt: Yeah, that's legs and tails. So we would really only recommend applying A tourniquet if bleeding is excessive. So, I mean, and what does that mean? You know,
Dr. Michael Kent: If you see something squirting.
Dr. Jamie Burkitt: If there's something squirting, yep. If you are applying pressure, the animal will allow you to apply pressure and bleeding is coming through your pressure bandages. You know, maybe there is some concern there. Of course, the amount of blood that can be lost from a Great Dane is dramatically different than the amount of blood that can safely be lost from a Chihuahua. So, everything is kind of, you know…
Dr. Michael Kent: Relative.
Dr. Jamie Burkitt: relative. That's exactly right. However, that being said, On the human side, and that's where all of our information came on this one, was only from the human side. There is absolutely no question that tourniquets save lives and people. Now, when a person is still conscious but bleeding and needs a tourniquet placed, they know that the person placing the tourniquet is trying to help them.
Dr. Michael Kent: Yeah, so they're not going to bite them, hopefully.
Dr. Jamie Burkitt: They don't bite, right? They may scream and it may be terrible and painful, but they're not going to stop the person doing it or try to stop the person doing it. I would say that of all of the recommendations we've made, this is the one that actually concerns me the most for caregiver safety.
Dr. Michael Kent: Both for applying a pressure and for putting a tourniquet on.
Dr. Jamie Burkitt: Really, yes. Because if you have a conscious animal, that whatever is bleeding that much is going to hurt a lot. So our recommendations, of course, as always, are for safety for the rescuer first. And then yeah, there is no doubt that tourniquets save lives. 100%, they do. So, we think that probably our recommendation here is going to land most relevantly to the first responder group. And there is the knowledge that it is possible that you may actually need to wait for the pet to be relatively lying down or lose consciousness before it is safe to do this, unless you have really good control of that animal.
Dr. Michael Kent: Like a basket muzzle.
Dr. Jamie Burkitt: Like a basket muzzle.
Dr. Michael Kent: Something else for your to-go kit?
Dr. Jamie Burkitt: Yeah. So, I think, there is no doubt that tourniquets save lives. Obviously, tourniquets need to be placed above the area of bleeding, in other words, toward the body, from the site of bleeding, and really need to be tightened down as tightly as you can do, which is, it feels scary to do that, but to save their life, it needs to be as tight as you can make it to the point that bleeding stops.
Dr. Michael Kent: And if you're driving to the vet and it's an hour away, do you release it every 20 minutes?
Dr. Jamie Burkitt: You do not. You leave it and drive. You just keep driving.
Dr. Michael Kent: As quickly and safely as you can.
Dr. Jamie Burkitt: That's exactly right. That's exactly right. And really, tourniquet release times matter, but at the same time, in the human medicine side, they're routinely having to leave tourniquets in place for one to two hours. Just this is reality for them as well. And so there is evidence on that. And their biggest worries, of course, is saving lives with high quality, same as us. But also, their priority of saving the limb is very, very high. And there is some controversy to this from an emotional standpoint as well. But one might argue that the value of a limb in a dog or a cat is less than the value of a limb in a human being. In that one limb, an animal can live a very happy life. Three limbed animal.
Dr. Michael Kent: Being an oncologist I know this. Tripods do great.
Dr. Jamie Burkitt: They're happy, happy, happy pets. So that may not be the same for a human being who requires a limb amputation. It's a really different story. And we respect that. And at the same time, saving the limb in a dog or a cat, it probably does not maintain the same priority that it does in a person.
Dr. Michael Kent: So if they're going to die otherwise.
Dr. Jamie Burkitt: Absolutely. Yeah. We would leave that tourniquet in place.
Dr. Michael Kent: I'm going to make another jump.
Dr. Jamie Burkitt: Do it.
Dr. Michael Kent: This is like an emergency room where you see case after case. A hot sunny day in California or somewhere else. Someone's left their dog or cat in the car maybe?
Dr. Jamie Burkitt: It does happen.
Dr. Michael Kent: And we see heat stroke. So when else does this happen besides the hot sunny car? What can happen with that? And then I kind of hope you could walk me through what are the signs that an owner's seeing in a dog in heat stroke? And then why is it bad? And then We'll get to treatment. Should you cool them down before you get there? What do we need to do? What's most effective? Alcohol on their pads, a fan, hosing them down? Like, again, make me smart.
Dr. Jamie Burkitt: I'm so glad we're talking about this one. I think in total, we're going to end up with, you know, a couple or three dozen recommendations throughout our first aid guidelines. But I have to say, I think this might be one of my very favorite questions because it is so incredibly relevant and because what clients or any caregiver to an animal does in this situation is 100% life-saving. So, I mean, the first part of treating heat stroke is prevention. So just like for children, we would never leave a dog or a cat locked in a car, really, on ideally any day. This is ideal.
Dr. Michael Kent: It can happen by mistake, too. I mean, we hear the tragic cases of children being left, and it happens with dogs too.
Dr. Jamie Burkitt: Absolutely does. Prevention, though, is incredibly important. I would also say to remember that some of our most devastating cases of heat stroke happen on the first warm days of the year. And that is because every single year we acclimatize, every single year we acclimate to more
Dr. Michael Kent: People and dogs,
Dr. Jamie Burkitt: People and dogs and cats, acclimate to warmer weather. So in other words, you know, you maybe live somewhere where the winter has been brutal and spring is the lamb and the lion that it is. It's so difficult, you know, so much back and forth with maybe wet weather and cold weather and my gosh, it's April and it's still snowing. I can't believe it. And that beautiful first day comes in springtime and you're like, we're going on a hike. And you go out there and take a four hour hike in 75 or 80 degree weather, Fahrenheit, which doesn't even to us sound that hot today. we think, 75, 80, not that hot. But that is actually the dangerous weather.
Dr. Michael Kent: And they're wearing a fur coat.
Dr. Jamie Burkitt: And they're wearing a fur coat and they haven't been in this weather for six months.
Dr. Michael Kent: And they have their winter coat.
Dr. Jamie Burkitt: It's their first exposure and they're walking for two hours. So I think that is the main thing is remembering that those first hot days of the year are very dangerous. Any day that feels hot to you is dangerous for them to be exercising. You know, a walk is okay. If there's ever a point though where your dog or cat, but cats generally don't participate this way, but where your dog lies down. on a walk, on a hike, they lie down. You need to respect them lying down and they're telling you they need to stop.
Dr. Michael Kent: Listen to your dog.
Dr. Jamie Burkitt: Yeah, they need to stop for a little while. Most dogs that are hot will pant. Panting is pretty much always seen in dogs that need to cool down. But panting is also seen in dogs that are perfectly happy and don't need to cool down and it can be behavioral and excitement, right?
Dr. Michael Kent: Yeah, they're happy, you know, they're playing ball.
Dr. Jamie Burkitt: But I think remembering that on those walks or you've taken them to the dog park, whatever the case may maybe, especially those first days of the spring, and also when it's really hot outside and you are feeling hot, if they are panting, panting is a sign that they are hot. They need to be able to drink water, fresh water. So if you're taking them to the beach, remember they can't drink that water. They need fresh water to drink.
Dr. Michael Kent: No, salt water would be bad.
Dr. Jamie Burkitt: And yet, We do see this too. And just remembering that anytime they act like they're tired, they need to be allowed to sit and rest and not push to do more.
Dr. Michael Kent: So what are the signs? You said panting.
Dr. Jamie Burkitt: Panting.
Dr. Michael Kent: Lying down, when maybe they would play otherwise.
Dr. Jamie Burkitt: Yeah, when they might otherwise play. Some of them though will play themselves to death quite literally in the heat. So you can't rely on them to lie down and tell you. So other signs would be disorientation. So just seeming not quite right.
Dr. Michael Kent: They're not quite there anymore. They're not your dog.
Dr. Jamie Burkitt: Not quite there, or they kind of stumble a bit or fall down at all. These would be really, really concerning signs, actually.
Dr. Michael Kent: Okay, so getting to first aid.
Dr. Jamie Burkitt: What to do?
Dr. Michael Kent: What to do?
Dr. Jamie Burkitt: Yeah. So this is another running water. And the running water part is really, really important. So we obviously never recommend dousing an animal anywhere in front of the neck. So we keep the water away from the nose and mouth.
Dr. Michael Kent: You don't want to drown them.
Dr. Jamie Burkitt: Which could absolutely accidentally happen. And we don't want to see that. So the best place to try and cool them with running water is on the least haired part of the body.
Dr. Michael Kent: So their belly.
Dr. Jamie Burkitt: The belly. That's what we recommend. So, aiming for the belly if at all possible. And really that large surface area of the abdomen compared to the paw pads is the important piece. Kind of in human beings, now human beings are really different here. So our recommendation is different. In human beings, there is a recommendation that it is reasonable if you can't full body dunk a person, because it's not always possible, you don't always have a full body dunk option. They can actually cool people by putting their hands and feet into water bath. However, this really is different for a dog or a cat. The surface area is different paw pads compared to hands and feet. Of course, the top aspects of paws have fur again. So it's such a smaller surface area than it is in people. And you can't like ask them to sit there with it. It's just simply not as effective. We run water over the belly.
Dr. Michael Kent: So you run water over the belly. Five minutes, 10 minutes, 15 minutes.
Dr. Jamie Burkitt: 15
Dr. Michael Kent: 15 minutes again. So this is easy, 15 minutes for caustic toxin exposure, 15 minutes for a heat stroke.
Dr. Jamie Burkitt: Minimum 15.
Dr. Michael Kent: And then get to the vet because there are…
Dr. Jamie Burkitt: Always, every time, every time go to a vet. So even if they seem really much better, you know, they fell over in the heat, seemed not quite right, maybe excessive panting, you've cooled them and you've done an effective job, 15 minutes at home, still strong recommendation for taking them to a veterinarian. There can be sequelae or results of heat stroke that happened three to four days later that really a veterinarian should at least be involved enough to have a baseline examination of the animal, even if it's looking pretty darn good, and make some offerings to you as far as any baseline testing they might recommend. They may, and they may not, which is also fine.
Dr. Michael Kent: Their core temperature might be normal when they see him and they went, okay, it was only 5 minutes. Maybe he wasn't really, he or she wasn't overheated.
Dr. Jamie Burkitt: Yeah. Recommendation from a veterinary professional though is really, really important there.
Dr. Michael Kent: This has been really cool. And I just, I know I told you we weren't going to go so long and we've already gone over, which I've done many times. And I mean, there's so many other things that we could talk about in first aid. And I guess the best I can do at the moment is say, I'd love to speak with you again when the guidelines are finalized and that we will post to our website a link there so you can find out other things. Can you maybe just give me a list of a couple of the other things that you guys are creating guidelines for, you know.
Dr. Jamie Burkitt: Within first aid?
Dr. Michael Kent: Within the first aid.
Dr. Jamie Burkitt: Oh yeah. So we do, a really exciting one, I think, is handling low blood sugar at home. So certainly, we have a lot of animals that are known diabetics who are just, can be fragile diabetics, just like people and can have low blood sugar incidents at home.
Dr. Michael Kent: And who get insulin at home?
Dr. Jamie Burkitt: Yeah, who are getting insulin at home. So I mean, that is a ripe area for evaluation, and we do have some recommendations coming out about that. We also have some recommendations that are aimed a bit more, like I mentioned, in first responders and canine officers. So the administration of Narcan in the field for drug sniffing dogs.
Dr. Michael Kent: For opioid crisis or for dogs who get into maybe their owner's medication.
Dr. Jamie Burkitt: Yeah, for sure. And oxygen provision on the way to the hospital and things like that.
Dr. Michael Kent: I'm actually really excited to see these come out. I think they're they are game-changing, right? And then our director, producer, Danae Unti, had a question that I hadn't really thought about so much, but Let's say you have goats or cows or a horse at home. You may not be able to just get them and transport them. Are there guidelines in the works for those? Like you have RECOVER guidelines for other species. Are we thinking first aid for some of our larger companions that we have?
Dr. Jamie Burkitt: That's a great question. So specific to first aid, I think almost all of our first aid guidelines will translate really well to other species. Because so many of them are sort of practical, hands-on measures that you can do for animals at home, like overheating or caustic substance. There is not going to be a difference there. In many ways, skin is skin. The covering of hair particularly depends a little bit on the species, but especially, you know, many goats might have very short fur. Same with horses, things like that, have very short fur that's actually almost more almost more directly applicable to a person than a dog that's real fluffy or something like that and maybe has a little more protection. So a lot of what we've recommended in first aid will be applicable across multiple species. And as far as looking into other species, yes, they almost certainly we will stick with domestic species or companion animals. So non-domestic companions as we evolve. But I do think over the next five years, we do have a full domain that is actively working right now, looking into life-saving measures for CPR and prevention of cardiopulmonary arrest in foals. And certainly, a non-domestics companion animal, for instance, for birds and reptiles and smaller mammals is very likely to appear in the next few years.
Dr. Michael Kent: I am sure I'm going to be imposing upon you and asking you back as more of this unfolds. And I'm actually interested in some of your other areas that you're interested. So I really appreciate you coming today to talk with me. I think this is going to be really helpful for people. And, you know, it's pragmatic advice on what to do in an emergency, right? How to stay safe, but try to save your pet's life.
Dr. Jamie Burkitt: Absolutely.
Dr. Michael Kent: So thank you for joining me today on The Vetrospective.
Dr. Jamie Burkitt: Yeah, thank you so much, Dr. Kent. Really appreciate it.
Dr. Michael Kent: Michael, please, Jamie.
Dr. Jamie Burkitt: Thank you for having me, and I appreciate it.
Dr. Michael Kent: No, this is great.
Dr. Jamie Burkitt: Yeah, you're welcome.
Dr. Michael Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E09: Osteosarcoma
- Read the Transcript
- Dr. Robert Rebhun: While we can't tell which ones are going to respond, and it's a very few, I think it gives us hope that we can make this happen.
Dr. Michael Kent: Hello, and welcome to The Vetrospective Podcast. This is your host, Dr. Michael Kent. I'm a radiation oncologist at the UC Davis School of Veterinary Medicine, an animal lover, and like I said, your host. On today's episode, we're going to be talking about osteosarcoma. So, osteosarcoma is the most common type of primary bone tumor that we see and meaning a tumor that arises from bone. For those of you who enjoy etymology, osteo comes from the Greek word for bone, sarcoma comes from the Greek word for flesh, and oma means morbid growth or tumor. Put it together and we have osteosarcoma. But of course, if you, your child, your dog, or your cat are faced with learning what this word really means, it can be life-altering. This is one of the cancers that we look at as having a true One Health approach. In other words, what we learn about this disease in people help us treat our patients, and what we learn in dogs can in turn help advance human treatments. We'll talk more about this during this episode.
So, to speak to you about this today, I have invited Dr. Robert Rebhun, who has worked on this tumor for much of his career. Dr. Rebhun is a professor and the Maxine Adler Endowed Chair in Medical Oncology here at the UC Davis School of Veterinary Medicine. Dr. Rebhun did his undergraduate work and his DVM. at Cornell University. They then earned a PhD in cancer biology from the University of Texas Health Science Center at Houston and MD Anderson. Before joining me at UC Davis, Dr. Rebhun completed his medical oncology residency at Colorado State. He works with me at our Center for Companion Animal Health, where he is our Associate Director for Cancer Research, and he is also Director of the Veterinary Center for Clinical Trials. Thank you, Dr. Rebhun, for joining us today, and welcome to The Vetrospective.
Dr. Robert Rebhun: Thank you.
Dr. Michael Kent: Okay, I wanted to ask you before we got started on osteosarcoma, what made you decide on veterinary medicine, and then why cancer?
Dr. Robert Rebhun: Yeah, so vet med was easy for me. My dad was a vet.
Dr. Michael Kent: At Cornell, right?
Dr. Robert Rebhun: Yeah, he was a professor at Cornell. He was boarded in ophthalmology and large animal internal medicine. So, I thought I wanted to be a dairy vet growing up in upstate New York.
Dr. Michael Kent: Lots of cows.
Dr. Robert Rebhun: And then through, I actually was interested in, I wasn't sure if I wanted to go to vet school or med school. And ultimately, I did some research work for a couple of years and decided that One Health was One Health and decided to go to vet school.
Dr. Michael Kent: And then cancer. What drew you to cancer?
Dr. Robert Rebhun: Yeah, I mean, cancer touched me in many ways. I think my father was actually diagnosed with a brain tumor my first year of vet school, which got me even more interested in cancer. And through the basic sciences and through vet school, I decided I wanted to do cancer instead of dairy cows.
Dr. Michael Kent: Fair. So, moving on to the topic we're going to be talking today, can you explain to everyone and even me, why not? I can always learn. What is osteosarcoma?
Dr. Robert Rebhun: Yeah, so I mean, as you mentioned, osteosarcoma is a primary bone tumor that affects usually large breed dogs and also kind of affects people, usually younger age adolescents, but occasionally older people do get osteosarpoma as well.
Dr. Michael Kent: So how common is this disease in dogs?
Dr. Robert Rebhun: Well, interesting in dogs, we estimate that there might be around 30,000 cases in the US per year. So, it's pretty, you know, it's one of the more common tumor types that we see in large breed dogs. as opposed to in people, there's only about 800 to 1000 osteosarcoma diagnoses a year in the US.
Dr. Michael Kent: What about cats? Do we know about cats and osteosarcoma at all?
Dr. Robert Rebhun: Not A lot. It's a pretty rare tumor in cats. And when we see it, they're usually, the ones I've seen is only a handful over 15, 20 years, and they're usually old cats.
Dr. Michael Kent: Yeah. So, you had mentioned large breed dogs. Is there a reason why we think they happen more commonly in large breed dogs than in our small breeds?
Dr. Robert Rebhun: I mean, we see a bunch of different cancers in large breed dogs, but osteosarcoma, I mean, it tends to be associated with taller dogs. We think that there are some genetic differences between large breed dogs that may predispose them to osteosarcoma, but we haven't nailed that down yet.
Dr. Michael Kent: Something else to work on. So how old and... Are dogs in general? You mentioned this is something that hits young adults, kids, and humans, but what about dogs? What age range do we see?
Dr. Robert Rebhun: Yeah, so there's what we call a bimodal distribution, which just means there's kind of two high points of when this can occur. It's usually, there's a subgroup that's between one and three years of age and then there's most of the cases that we see are probably between 7 and 9.
Dr. Michael Kent: So yeah, the ones that one and two, those are pretty uncommon, but do occur, right?
Dr. Robert Rebhun: Yeah.
Dr. Michael Kent: So, and when we're thinking about osteosarcoma in dogs, what bones do we see this develop in most commonly?
Dr. Robert Rebhun: Yeah, so most commonly we talk about appendicular, which just means the legs. So can be forelimbs, can be hindlimbs, but there are certain locations that is pretty common within the bone. So if we see x-rays and we see a lesion in a certain area and a certain breed, that unfortunately fits with osteosarcoma a lot of times.
Dr. Michael Kent: What about front legs versus back legs? Is there a predilection or a particular bone or a particular site?
Dr. Robert Rebhun: Yeah, I mean, I think it's a little bit more front legs than back legs in most of the studies. We have an expression away from the elbow and towards the knee.
Dr. Michael Kent: I never liked the, on the back end, the towards the knee.
Dr. Robert Rebhun: Yeah.
Dr. Michael Kent: But yes.
Dr. Robert Rebhun: Yeah, the forelimb, the away from the elbow usually works pretty well is what we tell the students. But the other one, you know, towards the knee is, they can be anywhere in long bones. Yeah.
Dr. Michael Kent: So I always think of it more kind of either up at the shoulder or down and what we would, commonly refer to us in the wrist and kind of in those bones there and the like. So do we know what causes this disease at all? What causes osteosarcoma?
Dr. Robert Rebhun: No. Again, I mean, we're looking at, you know, a variety of groups are looking at genetics. You know, there's certainly a breed predisposition that we see in certain large breed dogs, even more than other large breed dogs. And really the only other thing that has been known to be associated with sometimes surgery implants like TPLO, if they get their cruciates fixed surgically and put in implants, sometimes they've been associated with osteosarcoma. But it's really hard to nail that down as well.
Dr. Michael Kent: Yeah, it's hard to prove, right? Because if you have a lot of dogs getting this particular type of surgery, were they going to develop it anyway?
Dr. Robert Rebhun: Yeah. And I said, the predilection seems to be towards the knee and that's where the implants are for knee surgery.
Dr. Michael Kent: Yeah.
Dr. Robert Rebhun: It's hard to say.
Dr. Michael Kent: Yeah. And so where else do we see this, you know, besides in the long bones? You mentioned our appendicular skeleton or which means our long bones, our, you know, radius and humerus and the like. But where else do we see these pop up in dogs?
Dr. Robert Rebhun: We can see these just about anywhere, honestly. I mean, we can see them in the jaw. We can see them on the head. We can see them in the hips or spine sometimes. But most commonly it's in the legs.
Dr. Michael Kent: Yeah, most commonly. And then I know as a radiation oncologist, I often treat the ones in the nose also. So, we see them intranasally too. And so really, because it's a tumor that arises from bone, it could be anywhere bone starts, right? Anywhere we have bone.
Dr. Robert Rebhun: Yep.
Dr. Michael Kent: And so how is an owner going to know? What are the clinical signs? You know, we can't really say symptoms because symptoms are self-reported. So, what is an owner going to notice if their dog has osteosarcoma?
Dr. Robert Rebhun: Yeah, I mean, clinically, a lot of times what we'll hear from owners is that there was some incident. You know, we were jumping out of the car, we were chasing a squirrel, we did something, we were playing ball, and we noticed a lameness, so a limp. But a lot of times it's just kind of that little activity that kind of puts it over the edge, so to speak, because these are pretty painful. There's a loss of bone that's there. It can be quite painful for these dogs. So usually it's going to be a limp. Some dogs, you know, may start acting off, may not eat as much, but most times it's just, “oh, my dog's got a limp”. And it's hard to tell if that's a soft tissue injury or if they may have, hurt their ligaments or something?
Dr. Michael Kent: So yeah, this isn't really specific to a bone tumor, what you're describing, right? I mean, things like you said, like an injury or even arthritis, the dog is getting older because we're, you know, most of the dogs are older dogs who get this. So how would like you clinically approach this if you were, let's say, bring your dog into your local vet, are you immediately thinking bone tumor when the dog becomes lame after playing ball?
Dr. Robert Rebhun: Well, I am because I'm an oncologist,
Dr. Michael Kent: But we see a stilted.
Dr. Robert Rebhun: That shouldn't be the case. A lot of soft tissue injuries, again, knees, all sorts of things can cause lameness. So, I mean, I think just heading to the vet and looking at, having them look and do an examination. Usually if we see like deep bone pain on physical exam, that will be something that makes us want to do an x-ray. But if it seems like it's just a routine injury, a lot of these, it's reasonable. Majority of time, it's going to be, oh, let's get some rest and maybe start some pain medication and we'll recheck it in a week or two.
Dr. Michael Kent: And then if it comes back or it's still persistent, then it's probably worth getting an x-ray to try to investigate this further. So how else do we go about diagnosing this? Like how do we actually decide this is a bone tumor? How do we decide it's potentially an osteosarcoma?
Dr. Robert Rebhun: Yeah, so some of that depends on where in the country you are. So here in California, we don't have a lot of fungal diseases.
Dr. Michael Kent: Fortunately, yes.
Dr. Robert Rebhun: They can look a lot like this on x-ray. So that can be, painful lesion on palpation, on physical exam. And, if you're in the Ohio River Valley and, you do x-rays and you see a lesion that looks typical of osteosarcoma, you may also have fungal disease on there. And so getting a sample of that would then be the next step.
Dr. Michael Kent: So, can we just use the x-ray and the changes we see on an x-ray or a radiograph, a radiograph being the technical term for an x-ray to diagnose this, or you mentioned we might have to do more?
Dr. Robert Rebhun: Yeah, I mean, depends on where you are, but I mean, a typical x-ray here, we may be about 90%, but it's not 100%. And again, that's if it's a typical location, typical breed, typical everything, we can be pretty confident on an x-ray. But it's always best to try and get a sample to confirm that.
Dr. Michael Kent: Yeah. So, if we're looking at x-ray and we see this destructive and even productive type lesion on the x-ray, and I know this is audio, so I can't really show you a picture or one, but they're pretty striking, right? And so now that we see this, and what would be the next steps that we would take with the owner to decide on how to proceed.
Dr. Robert Rebhun: Yeah, I mean, if it's reasonable, we try and get a sample of it to see if we can confirm. Sometimes we can confirm tumor versus infection. That may be as far as we go, but once we know it's a tumor in the bone, then we know to address the pain and to address the tumor itself. And then we're probably heading towards surgery. And so, once we kind of know that, we will do what we call staging, is just searching everywhere else in the body to make sure it hasn't already spread somewhere.
Dr. Michael Kent: So staging is kind of assessing the tumor locally and then seeing where it may have spread or may not have spread, at least to a best ability we have, right? So
Dr. Robert Rebhun: Yeah.
Dr. Michael Kent: How do we go about staging it? What are the tests we use for that? and where are we looking? Where is it most commonly spread?
Dr. Robert Rebhun: Yeah, I mean, everything, it depends on the dog and the client in the situation, but most times we're concerned that it's going to spread to the lungs or other bones. It doesn't spread very commonly through the lymphatics. So, if we're looking at the lungs, we can do x-rays. We can also do a CT scan. And if we're looking in other bones, I mean, we want to do a good physical exam, see if we can pick up any pain anywhere else. If we do suspect some pain somewhere else, then we can do x-rays of that area or a CT scan or a few other tests. But those are the ones we usually use.
Dr. Michael Kent: Okay. And so let's say we have to advise an owner if we're going to do an x-ray or a CT scan to look for the lungs. What's kind of the advantages of each? or why would you choose one over the other?
Dr. Robert Rebhun: Yeah, I mean, our standard is usually x-rays. dogs may sit still for x-rays or they may need a light sedation or something like that. CT scans are great. You can see smaller lesions on them, so they're more sensitive. The problem in dogs, we don't have a long history of doing CT scans for chest and so when we see little things, even if we see what we're convinced are small growths in there, we're not really sure what that means long-term for the dogs.
Dr. Michael Kent: So they may or may not be the tumor. They could be even just like an old infection, like what we might call a granuloma or something, right?
Dr. Robert Rebhun: Yeah. So they're very sensitive. They're not as specific.
Dr. Michael Kent: Got it. So sensitive meaning we can find lesions more, but specific meaning we don't know if that's tumor or is that something else?
Dr. Robert Rebhun: Yeah, in some cases. And we know if we take X-rays and we see a tumor there or what looks like growths, that's a pretty poor prognosis and it's going to guide potentially what we decide to do.
Dr. Michael Kent: So how often have they already spread by the time a dogs diagnosed with this or that we have a high suspicion.
Dr. Robert Rebhun: The number that we say here or anywhere in academia is about 10%. I think there may be a higher percentage out there in the real world with general practitioners that take films and then take x-rays. If they already have spread to the lungs, they may not choose to come see us because the prognosis is poor.
Dr. Michael Kent: So, how do we go about treating this? You know, we have a dog who presents for lameness. The local vet maybe has put him on a non-steroidal anti-inflammatory drug for a little while. They rest him, doesn't get better. So, they take an x-ray and they're suspicious. They send him to us. So how do we talk to owners? What are our options for treating it?
Dr. Robert Rebhun: Yeah, I mean, so the biggest problem with osteosarcoma, I mean, we like to get a diagnosis, so oftentimes we will try and do fine needle aspirate under ultrasound guidance.
Dr. Michael Kent: That's where we put a needle into the tumor and try to get cells out, right.
Dr. Robert Rebhun: Exactly, yeah. And, or, you know, we could do biopsy, but most times we can get our answer with that needle into the lesion itself. Once we are confirmed that it is osteosarcoma or that it is a tumor, unfortunately the problem with osteosarcoma is that almost all of them have already spread by the time they're diagnosed.
Dr. Michael Kent: So spread meaning we can see the disease or spread.
Dr. Robert Rebhun: Yeah, so like I said, when we look on x-rays, the number is only 10% that we can see that have spread. Those are big tumors that have to be, they have to be bigger tumors to be seen on x-ray, but... We know this tumor sends out a bunch of cells. We call it microscopic disease. So, we know that the cells themselves have spread. And it's estimated that we need to see, in order to see a tumor, you probably need a billion or more cells.
Dr. Michael Kent: And a billion cells is what, going to be just a few millimeters or like a portion of an inch, right?
Dr. Robert Rebhun: Yep.Yeah. And so, you know, there could be a million cells there and we can't see it on x-rays. We can't pick it up even on CT scan. So that's the problem with this disease is at the time of diagnosis, in people and in dogs, probably 95 plus percent have already spread. We just don't see it.
Dr. Michael Kent: Okay, so I'm going to break it out a little bit then. So, we have a dog who comes in and it's got a suspected bone tumor in, let's say, above its wrist, its distal radius, most common, one of the most common sites we see. We aspirate it, It looks like tumor, not infection. We're in California, so that's unlikely. And we take chest x-rays and they're clean. What's our next step for treatment? What do we offer to the owners?
Dr. Robert Rebhun: I mean, that's where things differ a little bit in vet med versus human medicine. So, what we try and do is we try and match what the goals of the owner are, what the dog, it may depend on the owner, it may depend on the dog. but we have, five or six different treatment options that we can approach this with.
Dr. Michael Kent: Yeah. So, we're taking in the dog in the family and kind of holistically looking at that and trying to advise the owner on what to do. So, what would be our most commonly offered treatments? I know we don't like to use the term standard of care when we don't really have a standard.
Dr. Robert Rebhun: Yeah. So the, I mean, the most aggressive option, the, it's called, which I don't love either, curative intent option is to remove the primary tumor and then follow that up with some sort of therapy, usually chemotherapy. So, we get rid of the primary tumor. That can be most times, that's amputation, to get rid of the entire tumor. Occasionally we can do limb spare, but only in certain locations and in certain dogs.
Dr. Michael Kent: And those are with higher risks of complication too, right? So, you always have to weigh the benefit versus the potential complications and risks.
Dr. Robert Rebhun: So removal of the tumor, amputation is the most common, most aggressive way to treat this. We get rid of the primary tumor and then we need to talk about slowing down those cells that have already snuck out to other places in the body.
Dr. Michael Kent: So how do we, how do dogs do after you take a leg off most of the time? How do we expect them to respond?
Dr. Robert Rebhun: Yeah, I mean, our not so funny joke is that, you know, dogs have three legs and a spare. Most dogs do very well with amputation. It depends a little bit on the breed. I mean, really giant breed dogs, Forelimbs hold about 60% of the weight. And so, and it's more dramatic when we have a forelimb amputation because they have to hop and their head goes up and down.
Dr. Michael Kent: And with a giant breed dog your going to see that, their face is almost in yours.
Dr. Robert Rebhun: Yeah. So, you know, we say, you know, forelimbs are a little bit tougher. The hind legs, you know, may also depend like things like if we have severe osteoarthritis, if we had bad knees, something like that. But, In most cases, the dogs do very well.
Dr. Michael Kent: And they're getting up really within a day of surgery usually and just learning their new center of gravity so they don't topple a little bit, right?
Dr. Robert Rebhun: Yeah, I mean, depends on, like I said, if we get a... seven-year-old lab that's a hunting lab that the bone pain hurts so much, usually you're right. They get up from surgery, they feel so much better. And it's like trying to, how do you keep them in the hospital for a day? You know, big St. Bernards or something with a forelimb, they may actually take a few days to get up, get around. They might need a lot more help.
Dr. Michael Kent: So now you've already alluded to that we have to do more now after we've taken off the limb and that we have to, basically, we usually offer chemotherapy, right? So how effective is the chemotherapy? When do we start it?
Dr. Robert Rebhun: Yeah, so I'll kind of throw in a little comparative note here. I mean, when people, the standard is to actually start chemotherapy before you remove the bone tumor.
Dr. Michael Kent: What we would call neoadjuvant.
Dr. Robert Rebhun: Yeah. And then they typically get chemotherapy after the surgery as well. In people, chemotherapy is, it's a much more toxic protocol, which just means it's toxicity is, you can handle toxicity a little bit different in people. But chemo's actually much more successful in people. So probably 60 to 70% five-year survival and there can be long-term cures. In the dog, we typically just do the amputation or the surgery to get rid of the bone pain, and then we follow up with chemotherapy. And so can be anywhere from 4 to 6 doses of chemotherapy usually.
Dr. Michael Kent: And they're about every three weeks or so, right? So you're looking at a commitment and we're monitoring the lungs and and the like. How effective is it though? How, what, you said 60 to 70% effective at long-term control, at least for humans. What do we consider control and how long does it last?
Dr. Robert Rebhun: I mean, there's a variety of different studies. I would say the largest prospective clinical trial that's ever been done in dogs with surgery followed by chemotherapy. The median survival is listed as 280 days, which just means half the dogs live longer than 280 days and half the dogs live less than 280 days.
Dr. Michael Kent: So what, 10 months or something? And there's a huge range around a median though.
Dr. Robert Rebhun: So yeah, and the other way to put that is there's about a 40% survival at one year. And at two years, about 24, 25% of dogs are alive at two years.
Dr. Michael Kent: So it's pretty tough. So, what can we do then if, let's say a dog comes to us and they already have lung mets or spread to the lungs, sorry, using vernacular, or if they've gone through chemotherapy and it's in the lungs, where do we have really effective treatments for that?
Dr. Robert Rebhun: No, I mean, that's something that researchers have been working on for now 40 plus years. Human and dog, once it's spread to the lungs, there's not a lot that has been shown to work.
Dr. Michael Kent: So, you already alluded to a little bit of this disease in people. And you know, it's not as common. 800, 1000, you know, young adults, kids get this a year. And 30,000, and I've seen numbers even saying higher sometimes in dogs in the US getting this a year. How similar are they to each other? How similar is the disease in us, people, versus disease in dogs?
Dr. Robert Rebhun: Yeah, I mean, it is one of the cancers that we see that is quite similar. So, we talked about the age differences a little bit. But, if you look at these under a microscope, they're almost indistinguishable. If you look at them molecularly and genetically, they have a lot of similarities. Certain genes are upregulated and downregulated. There's a lot of similarity. And then clinically, like we mentioned, usually happens in the legs or the arms. And it usually spreads to the same places in both species.
Dr. Michael Kent: So really similar. Are there big differences besides the age distribution that we see? between people where it's younger people and older dogs most of the time? Are there other major differences that, we've found at this point?
Dr. Robert Rebhun: I can't really think of any, but maybe you can.
Dr. Michael Kent: Not off hand. That's why I was asking you. But so you, what we're saying in a sense is what we learn in people, we can apply to our patients and what we learn in dogs, we can hopefully apply to people, largely young adults. So, this is actually a really good tumor to study in humans and in dogs then.
Dr. Robert Rebhun: Yeah, I mean, I think, we talked a little bit about the variety of things that can, the variety of treatment options that we can do with dogs. So, I mentioned the most aggressive way, amputation followed by chemotherapy. But sometimes, if you've got an old dog or maybe a dog that already has severe osteoarthritis or something, we do have palliative options as well.
Dr. Michael Kent: Yeah, and I do some of those.
Dr. Robert Rebhun: Yes, you do.
Dr. Michael Kent: Yes. So you want to run through those for people?
Dr. Robert Rebhun: I mean, we talk about amputation alone just to relieve the pain. Like dogs may actually come in with a fracture where this bone is weakened and they're so painful. We, unfortunately the options are euthanasia or we remove the leg.
Dr. Michael Kent: Right then, yeah.
Dr. Robert Rebhun: And so some owners may just want to get a few more months and not want to do chemotherapy for their dog. Maybe they're, have somebody at home that's pregnant or trying to get pregnant and the secondary chemo exposure might be a concern for them. Maybe the dog, like I said, has got bad osteoarthritis or other orthopedic disease, and we just want to palliate. So, we can talk about palliative radiation. We come see you and give them radiation. Almost all of these dogs, we're going to be putting on pain medication.
Dr. Michael Kent: In addition, even to the radiation, I know we tell people we can usually get somewhere in three to six month kind of range of decent pain control. At least about 75% of dogs we treat begin to control it.
Dr. Robert Rebhun: I think that's the goal. With palliative, you know, we're looking at three to six months, like you said. Radiation works great. Some other medications may be helpful, but there are most cases options to palliate if they don't want to be aggressive.
Dr. Michael Kent: So, I wanted to bring us back to talking a little bit about people. In a sense, you've talked about how we've maximized the dose of chemotherapy and despite the toxicity. And in dogs, we use chemotherapy and we've also kind of maxed out what we feel is acceptable, even though we dose a little bit lighter and we still fail. and we fail 60 to 70%, if it's your kid, that's not where we want to be. That's heartbreaking. And so where do we go from here? How do we move this forward?
Dr. Robert Rebhun: Yeah, I mean, that's where opinion comes in.
Dr. Michael Kent: Of course, that’s what I want from you.
Dr. Robert Rebhun: That's where we sit right now. I mean, I think in people, like you mentioned, they've maxed out chemotherapy. They've tried even more aggressive protocols and it doesn't seem to add anything. Once it's spread to the lungs, chemotherapy doesn't seem to do much.
Dr. Michael Kent: No, it's too much disease, right? And it's maybe resistant because you've already had seen the chemo and the tumor in an evil Darwinian way has figured out how to get around it.
Dr. Robert Rebhun: Yeah, and dogs, the chemotherapy helps. Like you mentioned, when we just do palliative, we're looking at three to six months. We're looking at more like 10 months with chemo. So, but again, there are a subset, 25% alive at two years that do respond to chemo.
Dr. Michael Kent: Yeah. So worth doing.
Dr. Robert Rebhun: For us anyway, I think, their chemo does work. It works in a subset of dogs. Wouldn't it be great if we could know which dogs that it actually worked for? Which dogs, the tumor doesn't respond to chemotherapy.
Dr. Michael Kent: Because we have some fail early, even at a couple months, right?
Dr. Robert Rebhun: Yeah, actually about 1/3 of dogs fail right when, before they, or right at the time when they finish chemotherapy.
Dr. Michael Kent: And this is kind of new, this research you've been working on, I know.
Dr. Robert Rebhun: Yeah, we've been doing it for a couple years.
Dr. Michael Kent: So how do we move it forward? I'm going to throw out the word immunotherapy to you and ask you to kind of talk about that, because I know that's something you've been working on, we've been working on together also.
Dr. Robert Rebhun: Yeah, I mean, I will add that in addition to chemotherapy, there's other approaches, receptor tyrosine kinase, targeted, personalized therapies that for other cancers have worked great. They haven't done much for osteosarcoma.
Dr. Michael Kent: Yeah, because I mean, even some of the targeted therapies I have, I know if we give in the face of gross disease, i.e. we see lung spread already, lung masses or lung mets, it doesn't do anything.
Dr. Robert Rebhun: Yeah.
Dr. Michael Kent: So, how do we do better?
Dr. Robert Rebhun: Well, immunotherapy has also been kind of a swing and a miss on osteosarcoma on the human side. There have been trials looking at checkpoint inhibitors, which have revolutionized cancer treatment in people.
Dr. Michael Kent: So, for those of you who want to learn more about checkpoint inhibitors, we have an episode with Dr. Rachel Brady talking about immunotherapy. But briefly, a checkpoint inhibitor is something to try to reactivate the immune system, reactivate our T-cells so they're able to recognize and attack a tumor. Sorry to interrupt, but…
Dr. Robert Rebhun: Yeah. They haven't really, for sarcomas and osteosarcoma in particular, they haven't really been shown to be a benefit.
Dr. Michael Kent: So how do we move this forward? Because these are what we sometimes refer to as immunologically cold tumors, i.e. the immune system can't find them as opposed to, let's say, a melanoma which has lots of changes on it that and causes an inflammatory response. We've checkpoint inhibitors have worked well on their own there. What do we what do we try to do with osteo now? How do you tackle this?
Dr. Robert Rebhun: It's I think there's excitement over immunotherapy and the approach to immunotherapy. We just haven't found the right one yet. And so as you mentioned, yes, these are considered colder tumors. The immune system isn't recognizing them, but there may still be ways to get the immune system to recognize them. So, it may just be a tougher ask. We've got to figure out a way for the immune system not only to recognize them, but then release the brakes and make sure that they're attacking these tumors.
Dr. Michael Kent: So combination therapies. I always like to think radioimmunotherapy is going to be the key, but we will see. So, another kind of question I have is, how do you find this earlier? Like, we find this pretty late in disease. Is there anything that we can think of or anything we can do to maybe try to diagnose this earlier?
Dr. Robert Rebhun: It's really hard, honestly. I mean, sure, if you've got a giant breed dog and it has a wimp, you can rush in and take x-rays. The problem is, if you catch it super early, we may not be able to see it on x-rays yet.
Dr. Michael Kent: Yeah, this is a tough one. And so maybe down the road, we'll have more molecular tests and or could find gene signatures, but we just haven't been able to do that as of yet.
Dr. Robert Rebhun: Yeah, I mean, there are several groups that are working on blood tests to try and pick up, you know, what they call liquid biopsies that may be able to pick up circulating DNA from released from the tumor. But.
Dr. Michael Kent: It's not ready for prime time yet.
Dr. Robert Rebhun: Stay tuned. Stay tuned.
Dr. Michael Kent: All right, well, anything I should have asked you, anything I forgot to ask? Before I wrap up here, I want to just make sure if there's something we should talk about.
Dr. Robert Rebhun: No, I mean, I will say that I wanted to add with the immunotherapies that there are several studies in people and in dogs that look like, even though they're cold tumors, that there may be an immune response. And so there are certainly cases where we've seen things like, for example, when patients get an infection post-operatively, both in people and in dogs, it's been reported that they have a better outcome. So, stimulating the immune system in this tumor. And we've seen in clinical trials, I mean, we're still, we're trying immunotherapy here for metastatic tumors that are in the lungs. And we've seen some responses to immunotherapy. So, I think it gives us, while we don't, we can't tell which ones are going to respond and it's a very few, I think it gives us hope that we can make this happen.
Dr. Michael Kent: Hope and we have to figure out how to make more of them respond.
Dr. Robert Rebhun: Yeah.
Dr. Michael Kent: So, I really appreciate you coming here today to speak with me on the Vetrospective. So, thank you, Dr. Rebhun.
Dr. Robert Rebhun: Thank you.
Dr. Michael Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E08: Feline Infectious Peritonitis (FIP)
- Read the Transcript
- Dr. Terza Brostoff: Our success rate is really, really good. We went from 100% fatal to seeing mortality in these cats somewhere around 15 to 20%. That is a massive, massive improvement, but it's still not 100%. We are still losing cats to this disease, and that is unacceptable.
Dr. Michael Kent: Hello, and welcome to The Vetrospective. This is your host, Dr. Michael Kent, here to give you a perspective on topics surrounding companion animals in veterinary medicine. I'm a professor of radiation oncology at the UC Davis School of Veterinary Medicine. Today's topic is FIP, feline infectious peritonitis. It's an infectious disease that is really unique in how it works and how deadly it is. This disease often has outbreaks in cats who are housed in groups, whether this is catteries for cat breeders or shelter population. FIP is devastating, causing rapidly progressing clinical signs that, left untreated, lead to death. It was not that long ago that there was no therapy at all, and in the beginning, the first drug, which was not approved for cats, was literally being smuggled into the country to try to save kittens and cats who were affected by FIP. The treatment and prevention of FIP is a rapidly evolving area in translational medicine. Dr. Terza Brostoff is here to speak with us today about FIP and what we are doing to stop this disease. Dr. Brostoff is an assistant professor of immunology, having joined the faculty at UC Davis around two years ago. She did her DVM and PhD at UC Davis and then went into small practice for a few years before going on to do her postdoctoral work at UC San Diego. She is a diplomate at the American College of Veterinary Microbiology with subspecialties in immunology and virology. Thank you, Dr. Brostoff, for joining me today on The Vetrospective to speak about FIP.
Dr. Terza Brostoff: Thanks for having me.
Dr. Michael Kent: Of course. So before we begin speaking about FIP, why did you get into veterinary medicine? And maybe you could talk about what caused you to have an interest in immunology and virology in particular?
Dr. Terza Brostoff: Sure, yeah. So, I was one of those little kids who, from the time I could recognize a dog for what it was, would try to pet every single dog that I saw and wanted to be a veterinarian from the time I could say it as a little kid, according to my parents. So always knew that I wanted to go into veterinary medicine, but the research side of things and the virology side of things came about a little bit later in my life. I was fortunate enough to have worked with an amazing shelter veterinarian during my undergraduate education. And it really opened my eyes to there being more than just small animal clinical practice out there. And I really started taking an interest in infectious diseases. And what about a shelter environment made those animals so much more predisposed to certain types of infections compared to normal client-owned dogs and cats? And that sort of started me on this pathway. The immunology came about a lot later. I actually really didn't like immunology when I was studying it at first. But having chosen a career in virology and working a lot on vaccine development, immunology is a really important topic related to how vaccines work, why they work, and how they're different than getting a natural infection. And so I've kind of learned it on the side. And it's taken over my life in many ways, but it's been a fun ride.
Dr. Michael Kent: So, when you were in vet school here at UC Davis, you were in this unique program, the Veterinary Scientist Training Program, or what we call the VSTP. So, it's a combined DVM and PhD program. So why did you join this program and how did it prepare you for your career?
Dr. Terza Brostoff: So, I actually, the summer before I started veterinary school, started, I decided that I was interested in research and I started looking up different faculties' research interests. And I reached out to a handful of the faculty here that were working on projects I found interesting. And one of those faculty happened to be one of our amazing anatomic pathologists, Patty Pesavento. And at the time, she was working exactly on what I was interested in, on viruses that affect cats in shelters. So, I reached out to her and I said, “I have nothing planned for this summer before vet school. Is there any way I could come poke around the lab”? And she graciously allowed me to work with her that summer and I absolutely fell in love with the work she was doing and with her as a mentor and everything else is his history.
Dr. Michael Kent: I always like learning about people's paths and where they wind up because they're often really varied. And I know after you finished veterinary school and after you finished your PhD, you went into private clinical practice for a few years.
Dr. Terza Brostoff: I sure did.
Dr. Michael Kent: So, what brought you back to research and what did you learn in private practice that shaped your future career?
Dr. Terza Brostoff: So, I always knew, again, I was that little kid that wanted to be a veterinarian. And doing the dual degree program, it really gave me an idea of how important research is and how it shapes everything that we do in the clinic. After finishing that dual degree program here, I decided pretty early on that I wanted to spend some time in practice. I didn't know what that was going to look like, if it was going to mean that I did a residency, an internship, or if I just went straight into clinical practice. And leading up to my senior year, I loved clinics. I loved interacting with clients. I loved the patient care. And so I decided that I wanted to spend, I decided at that time five years exactly five years in clinical practice before I came back to academia. And three years in, COVID hit, and I decided three years was gonna be just enough. And so, I returned and did that postdoc in early mid 2020, but knew that was something I wanted to use to shape my academic career as well. I think those years in practice were invaluable. I had incredible mentorship at the practice that I was at, and I really got a good feel for what it means to be an on-the-ground veterinarian, how to communicate that to them, what is important for them, and really understanding what clinical research can do and how it can benefit the majority of our patients.
Dr. Michael Kent: So really it kind of cemented what you wanted to do in some ways, and then you're able to step back into a more academic kind of program.
Dr. Terza Brostoff: 100%, yeah. It's actually kind of similar to the concept of the way that we structure our dual degree program here, where you start with your first two years of basic science, and then you do the PhD, and you use what you learn in those first two years for your PhD, and then you learn what you use, what you learned during your PhD back again in the clinical years. So, it's kind of of the same idea, only taking it a couple steps further, I guess.
Dr. Michael Kent: Now I know your interests go beyond FIP, but I really wanted to talk to you about FIP today. Can you describe to me the feline coronavirus and how this relates to FIP, the disease entity we call feline infectious peritonitis?
Dr. Terza Brostoff: Yeah, absolutely. So ,cats, there's a virus called feline coronavirus, and it's actually a really, really common virus in cats. It is not very closely related to SARS-CoV-2. It's in a different subfamily, but it causes a really, really unique disease in a very small subset of those cats infected with feline coronavirus. So typically, cats will get infected with the normal coronavirus, pretty young, in their lifetimes. It may or may not cause a little bit of diarrhea, but most cats clear the infection without having much of a problem.
Dr. Michael Kent: So, an owner might not even notice that their cat was exposed to this coronavirus.
Dr. Terza Brostoff: Exactly. And a lot of cats are exposed to it at a young age, and we never know. We don't test for it. It's not usually clinically important in those cats.
Dr. Michael Kent: And what about the virus itself, how does it change or why does it cause critical disease in some of those cats?
Dr. Terza Brostoff: We don't have a really good understanding of exactly which cats are going to go on to develop FIP, because as I mentioned, a lot of them do get the virus pretty early in life. But the accepted theory at this point is that in a very small subset of cats, for whatever reason, the virus will actually undergo some mutations that cause it to leave its normal area where it hangs out in the cat, which is the GI tract, and it can actually spread everywhere throughout the body. And when that happens, the cat develops FIP, or feline infectious peritonitis. FIP with the virus literally anywhere in the cat's body causes really, really severe disease. And again, untreated is considered nearly ubiquitously fatal or 100% fatal.
Dr. Michael Kent: Yeah. So, if we have 1000 cats, do we know probably how many were exposed to feline coronavirus in their life?
Dr. Terza Brostoff: It depends a lot on what the cat did when it was growing up. So, cats that have spent a lot of time in a highly dense environment, as you mentioned earlier, cats that are coming out of breeder environments or from shelters, those cats that have a lot of access to other cats and other cats' litter boxes tend to be more likely to be infected. And some of the estimates range in the high 80s to even 100% of cats in those environments. are frequently found to have been infected with the virus. Of course, we don't know quite as much from our community cats because we don't test them, but it's likely that those cats have a much lower prevalence of coronavirus if they are outdoor cats that grew up outside and spend their whole lives outside because they're not coming into quite as much contact with other cats and with other cats' poop.
Dr. Michael Kent: Fair enough. And so if we have, 1000 cats have been exposed to the feline coronavirus, you said a very small percentage. Do we have an idea of how many are going to have, at least current theory, that they have the mutations that happen that make this a more virulent virus, a more aggressive virus that's going to cause this disease entity?
Dr. Terza Brostoff: And again, it depends on a lot of things as well. There have been studies that have published as low as 0.5% of those cats, and then some say in certain environments, up to 10%. We know that genetically related cats, if one of the cats in a litter gets FIP, it is more likely that other cats from that particular litter are going to go on to develop it. That's likely where those higher percentages come from, is groups of cats that are highly genetically related. But in general, most of our estimates at the low end are around 0.5 and up to about 2%. That's considered typical.
Dr. Michael Kent: So, there's some predispositions some cats or kittens have to developing this in some ways. So, it must be a body host virus interaction to some degree.
Dr. Terza Brostoff: Yeah, absolutely. There's likely contribution from the cat's genetics and likely the cat's immune system plays a role as well. There's also likely some contribution from that actual initial virus that's infecting the cat. And we know there's different types of viruses that seem to behave a little bit differently in different cats. So, all of those.
Dr. Michael Kent: Different strains of the feline coronavirus.
Dr. Terza Brostoff: Yeah.
Dr. Michael Kent: Just to put in a little more understandable terms for me. So, I know there's different clinical forms of this. The 2 main forms, at least that I've heard broken down are the dry form of FIP and the wet form. Can you kind of describe those clinical scenarios that we see in kitties and kittens and cats?
Dr. Terza Brostoff: Yeah, so when cats first get FIP across the board, whether they have the dry form or the wet form, the first thing owners typically see is just a cat that generically doesn't feel good. So, these kitties have low energy, low appetite, they might not be playing, they're usually young, so they might not be playing with their litter mates as much, they might be hiding more. The wet form is the most common form that we see clinically, and it happens when fluid starts to build up in any one of the kitty's body cavities. So it can happen in the belly, it can happen in the chest, it can actually happen in the heart sac as well. And it can be any combination of those cavities that fluid can build up in. That's by far and away the most common form we see. And sometimes owners will notice it looks like their kitten is getting rounder and having a big, big belly.
Dr. Michael Kent: So, something that most people say, they need to be dewormed and maybe they just have general malaise or flu-like symptoms or clinical signs that are non-specific and then they become pretty ill.
Dr. Terza Brostoff: Yeah, exactly. And they can. They do absolutely look like a kitten that needs to be dewormed. But if left long enough, it will definitely get a lot worse than what we see with worm bellies. And again, in a kitten that feels really, really sick.
Dr. Michael Kent: And then what's the disease course if we can't intervene?
Dr. Terza Brostoff: So the disease course, whether they have the wet form or the dry form, and again, dry form, those cats typically act very similar to the wet form cats. They just act like they're not feeling well. Sometimes we'll see some involvement in the eyes or in the nervous system. They'll get wobbly and have a harder time walking, potentially having seizures as well. But regardless of the form, they will go on to feel more and more ill, stop eating, stop drinking. And again, without antiviral therapy, without intervention, most people agree it's nearly, if not 100% fatal in these cats.
Dr. Michael Kent: 100% fatal is pretty serious.
Dr. Terza Brostoff: It is, yes.
Dr. Michael Kent: So just a few years ago, this was considered untreatable. Do supportive care, but pretty much like you said, 100% of these cats died. And that was even with the best supportive care we could give them. So, what changed this? What happened?
Dr. Terza Brostoff: So, we're, it's fortuitous that we're here at UC Davis. We played a big part in this story as it's unfurled in curing FIP. So ,one of our faculty, one of our emeritus faculty, Niels Pedersen, helped discover one of the antivirals that we use today to treat FIP. It's got a really a name that just rolls off the tongue. It's called GS441524. That drug is actually really closely related to one of the major antivirals that was used in the COVID-19 pandemic or remdesivir. So, they're metabolites of each other. So very, very closely related and likely that Dr. Pedersen played a role in our ability to use that drug during the pandemic as well.
Dr. Michael Kent: And I know he'd I've been studying this for years. So why did it take us so long to come up with a treatment? Did we just not have the drugs? Did we just not think about it? I know this has been a disease that for decades we've really fought hard and lost.
Dr. Terza Brostoff: Yeah. So it did take a very long time for him to discover it and there were problems with licensing its use in the United States. And because we knew how effective it was, a black market popped up very quickly developing this, getting access to this drug, primarily from some pharmaceutical companies in China. And so for many, many years, people were buying this drug on the black market because it was literally the only thing available that could actually save these cats. And that market to this day has been very, very successful and has saved a lot of cats' lives.
Dr. Michael Kent: Yeah. So how does, I've got this right, GS441524 work? Like what is the antiviral doing? Is it killing the cells that are virally infected? Is it stopping the virus? How does it work in general?
Dr. Terza Brostoff: Yeah, so it's called a nucleoside analog, and it prevents the virus from being able to replicate. So, the virus has an enzyme that it encodes for, and that enzyme is meant to make more virus. So it makes the virus genome unable to reproduce. And when this drug, this drug fakes the virus out. It makes the virus think that it's one of the building blocks that it should use to make more virus, when in fact, when it uses that particular building block, the one that comes from the drug, it actually stops the virus from being able to do anything more with its own genome. So it stops the virus from being able to make more virus inside the cell.
Dr. Michael Kent: And you said it's been pretty effective, but what cases does it not work in? It's not 100% effective, is it?
Dr. Terza Brostoff: No, it's not. Most of the studies that we have at this point, because we actually have years of data, and this drug was actually being used pretty extensively in other parts of the world before we started using it as much as we have here in the United States. So, there are a good handful of papers that were published before we had it available here legally. And most of these papers show that efficacy is around 80 to 85%, depending on the study that you read. Most of the time, if kitties don't respond to the drug, it happens within the first few days to a week or so. And the prevailing theory, although we don't have enough data on this yet, is that we just caught those cats too late. So FIP is really, really difficult to diagnose, and especially in those dry form cats, where we don't have fluid building up in one of their body cavities, it can look like a lot of different diseases, and we don't have one very, very good, easy-to-do diagnostic on a live cat that gives us good certainty that cat has FIP. So that 80% is, for the most part, kitties that we likely didn't get to in time, and they were too systemically compromised to make it long-term. We do see a small percentage of cats who relapse, and we're still in the process of defining what exactly relapse means, because it's really, really hard to prove that it was that same first coronavirus that infected a cat, causing its FIP and then coming back, or never being eliminated by the antivirals. But there are a percentage of cats that do relapse when they come off of drug. And that contributes to that 80 to 85% as well.
Dr. Michael Kent: So, what other tools does a clinician have in their toolbox? If I'm just going to call it GS, it's easier. If GS fails and we suspect that FIP either wasn't cleared or is coming back, what else can we do? What else do we have out there?
Dr. Terza Brostoff: So, there's a lot of research and lots One of it has come out of UC Davis, along with Dr. Krystal Reagan and now our new internal medicine specialist, Erin Lashnitz.
Dr. Michael Kent: Who we talked about fleas with already.
Dr. Terza Brostoff: Yeah, so we have a big FIP community and we are, this is a huge part of FIP research now, is looking into beyond GS, what other drugs we can use to treat this disease. So ,there are other nucleoside analogs that we can use.
Dr. Michael Kent: Other antivirals.
Dr. Terza Brostoff: Yes, other antivirals. Antivirals of the same class, and some... some of different classes as well. So. there are trials looking at, again, specifically remdesivir. There's been a lot of work done on molnupiravir and some of molnupiravir's related compounds. And we also have a trial right now looking at Paxlovid to treat these cats.
Dr. Michael Kent: So, these are many of the same drugs that are used to treat viral infections in humans or even in COVID more recently with the pandemic.
Dr. Terza Brostoff: Yeah, absolutely.
Dr. Michael Kent: So, I know there's been an FIP vaccine that's literally been out for several decades. So why has this vaccine failed to protect cats from developing FIP at this point? How do you know that?
Dr. Terza Brostoff: There is one USDA-approved vaccine for use to treat or to prevent FIP in cats. It was developed in the 1980s. So, this virus has been around for a while. It was first described in the 60s and we had a vaccine in the 80s. There are a couple of reasons why in general this vaccine is not recommended for use in cats. It is, so we didn't talk about the two types of, we talked about the types of FIP, the wet form and the dry form, but the virus itself, there's actually two different genotypes. So, two different viruses that look very different on that outer spike protein. So, spike has become very famous because it's the target of the COVID-19 vaccine. And we have two types of feline coronavirus, type 1 and type 2. And the big difference between the two is that spike protein.
Dr. Michael Kent: So, a spike protein is just something that sits on the surface. And what does the spike do?
Dr. Terza Brostoff: Yeah, so the spike is one of the most important proteins on the virus for its structure and for getting into cells. So that spike has what we call the receptor binding domain on it. That's the portion of the virus that it uses to attach and enter into the cells that it's going to infect. So, it's a really good target for a vaccine in theory, because if you can get an immune response to that part that the virus needs to get into a cell, and if you can block that, you can block the virus from getting into any further cells. So, it's a really common target that we would use in vaccines normally.
Dr. Michael Kent: no, I kind of got you off topic a little bit, right?
Dr. Terza Brostoff: Sorry, I could talk about FIP all day long.
Dr. Michael Kent: Oh, that's good, because I may just hold you to that. No. So we were talking, oh gosh, what were we talking about? We were talking about how the original vaccine from the 80s, why it's not recommended now.
Dr. Terza Brostoff: Yeah, so there's the type 1 and type 2 spike. And type 1 is by far most common in the world. We see type 2 infections pop up sporadically, but they are less than 20% of the infections that happen in most cats. The theory behind that vaccine is getting a good immune response to that spike protein, and unfortunately, that vaccine is a type 2 spike. So we don't get protection from both, out of spike alone.
Dr. Michael Kent: It doesn't cross-react.
Dr. Terza Brostoff: Exactly, yeah. So, a cat that's immune to type 2 can still get infected with type 1 and vice versa. So, this vaccine is against the type that is less common in circulation in cats. It's one of the big problems with that vaccine. The other big problem is that the feline coronavirus, or FIP, is a little bit unique in that antibodies, which are one of the body's primary ways of preventing infections, typically help if you have a good antibody response to a vaccine, that's going to protect you from the virus, from disease. In feline coronavirus, in FIP, we know there are certain types of antibodies primarily to that spike protein that can actually paradoxically make disease worse. And so we have to be really careful when our major target for a vaccine is that spike protein that we don't actually end up causing the animal to develop antibodies that are going to make disease worse.
Dr. Michael Kent: Maybe make the virus get into the cell better, or do we know why that happens?
Dr. Terza Brostoff: Yeah, so it's a little bit complicated. So, antibodies normally bind to the outside. So ,antibodies to spike would bind to the outside of the virus because spike is on the outside surface of the virus. The enteric form or the GI form, that normal feline coronavirus that most kittens get, the target for the virus is cells in the GI tract. We know that with the mutated FIP form, the virus actually starts infecting instead of just cells in the GI tract, it preferentially starts infecting some of the white blood cells in the body. They're called monocytes and macrophages. Those cells actually have receptors for antibodies. And so a virus that is bound to antibodies can actually get into its new target, those monocytes and macrophages, those white blood cells, easier. So, we see higher mortality and faster mortality in those cats that are showing this antibody enhancement of infection.
Dr. Michael Kent: So those cells, which are just doing surveillance, actually wind up, in a sense, getting enhanced infection because of it.
Dr. Terza Brostoff: Yeah, and the virus can get around the body easier, faster, and more efficiently if it can get into those cells better.
Dr. Michael Kent: And I know you said that the coronavirus that infected humans and created the SARS COVID-19 pandemic or COVID as we know it, is a different subclass of virus than the coronavirus in cats. And I know the coronavirus in cats, as you were talking about, is at least largely GI and not respiratory to the start. So, what have we learned from the human pandemic that we can bring back to cats?
Dr. Terza Brostoff: Yeah, so we've learned a handful of things, and I think those of us in the FIP world are all across the board grateful that COVID-19 looks nothing like FIP in cats, because it's a very,
Dr. Michael Kent: very... Yes, when I heard it was first a coronavirus, I went, Oh God, I hope it's not this 100% fatal disease that we're seeing in cats.
Dr. Terza Brostoff: Yeah, and I think as well, a lot of us who are really entrenched in the FIP world, we were really worried when all of the vaccine strategies for COVID-19 were, for the most part, targeting that spike protein.
Dr. Michael Kent: Targeted spike wasn't going to make disease worse.
Dr. Terza Brostoff: Yeah, exactly. And it does not seem to be the case. Thank goodness.
Dr. Michael Kent: Thank goodness, yes, because I know I've had six or seven shots now for COVID.
Dr. Terza Brostoff: I think most of us have at this point. And thank goodness that vaccine was very safe, very effective. And we do not see this antibody enhancement of infection. I think we've done a worldwide epidemiologic study at this point. We can confidently say that is not a player. We don't see vaccinated people getting worse disease for sure.
Dr. Michael Kent: No, in fact, it's the opposite, right?
Dr. Terza Brostoff: It absolutely is, yeah. But I think, you know, no one really expected mRNA vaccines to take off, in in the world in general as far as vaccine platforms go. And I think this was the first widespread big use of that type of vaccine, which had been developed for years and years and years before the pandemic, primarily actually in your field of specialty, looking at its use in cancer vaccines.
Dr. Michael Kent: In a treatment vaccine, but not a preventative vaccine.
Dr. Terza Brostoff: Exactly, exactly, yeah. So, I think that was the other big thing that we've learned is that there's a new potential platform that we can use that seems seems to be really effective and quite safe.
Dr. Michael Kent: So I know you've been working, we have a pretty large FIP group here that's really transdisciplinary. You know, everyone from our basic or fundamental scientists and those who are translational scientists to those clinicians on the front line who treat these cases. And the unique idea of quote unquote bracketing the cat, I think maybe Dr. Pesavento, who you mentioned earlier first, I'll have to get her on this show. First coined it, but could you explain what we mean by the term bracketing the cat?
Dr. Terza Brostoff: Yeah, we do. We have a lot of researchers working on a lot of different aspects of FIP here at UC Davis. So, lots and lots of research going into the basic science, just understanding better how this virus gets in and causes the disease it does. But looking at it from the front end of the cat, so vaccine development and prevention all the way through to the back end. So treating it and developing better antivirals, publishing more data so that we know how best to use these antivirals, what doses, what drugs, how long to use them for, et cetera. That's what we mean by bracketing the cat, encompassing this disease from nose to tail.
Dr. Michael Kent: And understanding the whole mechanisms, how it works, and some of this is still a mystery.
Dr. Terza Brostoff: Oh, a lot of it is still a mystery.
Dr. Michael Kent: So, we have drugs like GS that we talked about and others like Paxlovid or remdesivir. And there's other antivirals I know that you mentioned as well. Why do we need a vaccine? We can just treat. What's the unmet need? Why should we have a treatment? Sorry, a preventative vaccine.
Dr. Terza Brostoff: Yeah, there's a handful of downsides to having to treat a disease after it's already developed. As I mentioned before, our success rate is really, really good. We went from 100% fatal to seeing mortality in these cats, somewhere around 15 to 20%. That is a massive, massive improvement, but it's still not 100%. We are still losing cats to this disease, and that is unacceptable. Additionally, again, we don't really know what the perfect drug for any particular cat is or how long we're going to have to treat any particular cat for. But at the present time, treatment still remains quite expensive. It's on the order of a couple thousand for a full course of treatment as we tend to prescribe it today.
Dr. Michael Kent: We were talking about shelter cats, breeders. This would be too expensive for shelters to bear the cost of this and for many breeders too.
Dr. Terza Brostoff: And for most pet owners. Most pet owners can't afford to treat their new cat that they just brought into the household that they expect to be at least mostly healthy for at least the next 10 years. And then right off the bat, they have a cat that requires hundreds, if not thousands of dollars of diagnostic tests and hospitalization, and then a couple thousand just to treat the cat.
Dr. Michael Kent: These drugs are human drugs, so they're quite expensive and still mostly on patent, right?
Dr. Terza Brostoff: Yeah. Yep. That's one of the problems for sure. The other problem, of course, being that mortality rate, that no matter what we do, even if even with all the money in the world, some of these cats still can't be saved.
Dr. Michael Kent: So I know you've been working very closely with others at developing a vaccine. So why could this one work when the previous tries at making an effective FIP vaccine have failed? How are you thinking about this? How are you thinking out of the box?
Dr. Terza Brostoff: Yeah, so we are using a totally different strategy than what's been tried for cats in FIP before. We're actually targeting a different protein. So, I mentioned that spike protein on the surface is the one that's potentially problematic when it comes to vaccinating cats and making disease worse, we're actually targeting one of the proteins that's present only on the inside surface of the virus. So, while the cat may develop antibodies to that protein, those antibodies won't stick to the outer surface of the virus, and they won't help the virus get into its white blood cell target that it likes to get into. So we're doing that, and in addition, we're using the mRNA vaccine platform, which to date has not been published on in cats.
Dr. Michael Kent: So, can it still find the target if it's hidden on the inside of the cell?
Dr. Terza Brostoff: Yeah, so it seems like a kind of kooky strategy if all I've talked about is antibodies preventing infection. And I'm saying antibodies aren't going to hurt the cat, but they're not necessarily going to do anything to help these cats survive and protect them from FIP. So, there's two arms of the immune system. There's our antibody arm, that humoral arm and there's actually the other entire other half that we don't tend to talk about as much because it's harder to study. But there's half of the immune system ish is dedicated to a particular cell type, a white blood cell that can actually recognize and kill cells that have already been infected. And so.
Dr. Michael Kent: Natural killer cell?
Dr. Terza Brostoff: Nope.
Dr. Michael Kent: Nope, not that one.
Dr. Terza Brostoff: That would be too logical.
Dr. Michael Kent: That would be too logical. And that's part of the innate system, but what cell are you talking about?
Dr. Terza Brostoff: Yeah, so the cell type I'm talking about, they're called cytotoxic, so cytocell toxic killing, cytotoxic T cells. So, we have B cells that make antibodies, and we have T cells. And one of the types of T cells, and the one that we're really banking on for this vaccine helping with, are called cytotoxic T cells. Our theory is that we are going to get really, really good immune community via the cytotoxic T cells. And they're going to recognize infected cells either after the cat's already been infected before the vaccine or afterwards and wipe out that reservoir before the feline coronavirus has a chance to mutate to that FIP form.
Dr. Michael Kent: So how far along are you? the $1,000,000 question.
Dr. Michael Kent: And hopefully not going to cost $1,000,000. I know this is it's hard.
Dr. Terza Brostoff: It absolutely is hard, and that is something that we are very conscious of. We are at a point where we have a vaccine in hand, and we've done some preliminary tests in cats. And at this point, we're trying to see if we can get an industry partner to start moving this vaccine forward.
Dr. Michael Kent: That's really exciting. So, what do you say to someone now who's just adopted a kitten and who becomes ill with FIP or caring for their cat who has FIP? Putting your clinician hat back on and your scientist hat back on, what would you say? What would you say to someone?
Dr. Terza Brostoff: About the vaccine or just in general?
Dr. Michael Kent: Just in general, vaccine and treatment and because this has been such a devastating disease for cat owners for so long.
Dr. Terza Brostoff: It is remarkable to be able to look an owner in the eye and tell them that we can actually save their cats. We've had so many clinical trials here at Davis and so, so many grateful owners. I had one in particular. She is a veterinary technician who's been in the field for many years and her own cat developed FIP and was enrolled in one of our clinical trials. And she cried at every single appointment because when her cat first got the diagnosis, she was devastated. And that devastation and then realizing that this is something we can actually treat now was overwhelming for her. So, it's so powerful to be able to literally save lives because we do a lot of medicine during the day and it's rare that we actually save a life, not to mention the life of a young kitten, you know, who…
Dr. Michael Kent: Who's so sick
Dr. Terza Brostoff: Who's so sick and who has a whole lifetime ahead of them.
Dr. Michael Kent: Yeah, that's very cool. And now I know a lot of people have heard of FIP, but more people are more familiar with some of the other viruses like FeLV or FIV. How different is FIP from these diseases?
Dr. Terza Brostoff: FIP is its own beast. It is, this is the only coronavirus we know of in cats. And it's really, really different than things like retroviruses, some of those other viruses we think of more commonly. And the disease itself is absolutely a one-off. We tend to think of either, these retroviruses and these chronic persistent diseases, things like feline herpes that the cat lives with its whole life, versus other acute viral infections, things like feline calicivirus or feline panleukopenia virus, where they get sick acutely over a short period of time. And if they survive that infection, they're usually, it's a one and done. FIP is really different. These cats are kind of, yeah, they're kind of sick for a period of time. They get the virus, they, and then weeks to months later, they break with a really, really severe disease, potentially even years later with a really severe disease. And it's definitely unique as far as viruses go, unique in a bad way.
Dr. Michael Kent: So, I'm gonna wrap us up by asking what more do we need to learn about FIP? What key pieces of information do you want to know so that we can bracket the cat?
Dr. Terza Brostoff: This is so this is the this is the Dr. Brostoff question and not what the field wants to know. The field is definitely moving towards we need better diagnostics.
Dr. Michael Kent: We need a test. We need blood tests. We need something.
Dr. Terza Brostoff: Something simple, something we can do non-invasively, something we can do quickly.
Dr. Michael Kent: With the snap test we have for FeLV and FIV, which we don't have for FIP.
Dr. Terza Brostoff: Exactly. The problem is that these cats are all infected with feline coronavirus. So just finding that virus there doesn't tell us that the cat has FIP. My $1,000,000 question, the avenue I am most interested in is what immune responses are actually protective in these cats? Because we know so many cats go on to clear their infection or never develop FIP. That's the vast majority of cats. But what is it about the immune response that is allowing some of these cats to get so sick, because we know a lot of the disease that we see from FIP is actually the cat's immune response to the virus.
Dr. Michael Kent: So it's basically saying, oh my God, I'm infected. And then the response from the cat is so strong. that it can actually kill the cat.
Dr. Terza Brostoff: Yeah, exactly. So that's where my research is headed, is figuring out what type of immune response is going to be protective and why most cats do fine. What are they doing differently in terms of immune response than cats that succumb to FIP?
Dr. Michael Kent: This has been really great. I appreciate you taking the time today to speak with me and The Vetrospective listeners. So please keep up the good work.
Dr. Terza Brostoff: Thanks so much. I had a great time too.
Dr. Michael Kent: Thanks.
The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E07: Artificial Intelligence
- Read the Transcript
- Dr. Keller: I'm very excited about the opportunities, but also a bit concerned about us getting complacent and not checking things as thoroughly as we surely should.
Dr. Kent: Shortcuts are dangerous.
Dr. Keller: Yeah, absolutely.
Dr. Kent: Hello, this is the Vetrospective podcast and I'm Dr. Michael Kent, a professor in radiation oncology at the UC Davis School of Veterinary Medicine and your host. Artificial intelligence. It's in the news daily and seems to be integrating into our lives, with most of us only having a vague understanding of what it is and what impact it holds for us. Well, no one really knows what impact it's going to have on all our futures. Is AI going to be no more than a hyped up productivity tool, or is it going to cause massive disruptions in healthcare and other industries? Will this be a productive disruption, ending in better outcomes for patients, or will it erode the humanity in our healthcare system?
On today's episode, we are talking about AI and how it's being used in veterinary medicine and what the future might hold for all of us. I've invited Dr. Stefan Keller to join us today to take a look at this. Dr. Keller is an associate professor in anatomic pathology here at UC Davis. He did his veterinary school in Berlin and did his residency work both in Zurich and here at UC Davis, where he also received his PhD. He is a European diplomate in anatomic pathology. And Dr. Keller works to bridge, really, the diagnostic pathology, immunology, and the rapid evolving field of artificial intelligence, why I invited him here today. His research group develops and deploys machine learning tools to improve diagnostic precision in veterinary medicine, including ANNA, an open-source analytics platform that links AI models directly with an electronic medical record system to support real-time interpretation of clinical and pathology data. Dr. Keller has contributed to areas such as clonality testing, immune repertoire sequencing, and an AI-assisted histopathology platform. He also teaches immunology and pathology, mentors graduate students, and collaborates with clinicians and computer scientists to help integrate AI thoughtfully and responsibly into everyday diagnostic workflows. So, Dr. Keller, thank you for joining me today on the Retrospective.
Dr. Keller: Thanks for having me, Michael.
Dr. Kent: Of course. So first, I want to ask you why you became a veterinarian and what made you interested in pathology?
Dr. Keller: So, I guess I started out firsthand thinking I could be a wildlife veterinarian and travel to cool places and see exotic animals. So, like the combination of being a veterinarian and adventurer, I think, initially lured me in. But then as you go through the DVM program, you kind of learn to see some realities and you explore or find things that you haven't really paid attention to before. And so I came across pathology and pathology... really intrigued me because it gives you a chance to look at the cause of disease and then the molecular and cellular events that that then lead to a clinical manifestation. So in other words, it allows you to kind of dig deep and understand, I think, disease on a kind of more deeper level. I think as practitioners, we are oftentimes restrained by financial resources of owners, for example, and are just technical abilities. And so pathology, For those of you who are not familiar with what pathologists do, we essentially are an atomic pathologists, which is a subspecialty of pathology. We look at tissue samples under a microscope. So biopsies.
Dr. Kent: Biopsies or post-mortem exams, what we would call a necropsy.
Dr. Keller: Correct, absolutely, yes. So, sitting at the microscope, looking at the cellular level of tissues is just very rewarding and oftentimes offers an insight in why a certain disease developed.
Dr. Kent: Interesting. And so in a sense, this deeper diving in and trying to figure out the causes of disease leads us over to your work in artificial intelligence as well. So, I've seen artificial intelligence, the concepts broken into many different classification systems, ranging from its capabilities in thinking, to tasks it can carry out and how it learns. I think what many of us have interacted with are the online AI platforms using specific applications that can do specific tasks, such as creating an image or writing an e-mail or writing a letter. Now, can you explain to me the different types of AI that are available to us? Specifically, maybe what is the difference between, let's say, generative AI versus machine learning, or maybe I'm missing the categories totally?
Dr. Keller: No, that's absolutely, it's a confusing a terminology and field because there's so many aspects and angles to look at it. AI started out in the 1950s, essentially, and just basically means that we have a machine that kind of does things akin to what humans would do. So, kind of AI is just a very general umbrella term for any computer system that mimics human intelligence. And so then machine learning. And so initially that was done creating rules, meaning that we could say, for example, in the field of veterinary medicine, if we wanted to interpret blood work, we could create a rule that says if, you know, the hematocrit is below a certain value, then we could call it anemia.
Dr. Kent: So hematocrit meaning what percentage of red blood cells you have in your circulation.
Dr. Keller: Exactly, right. So it's just essentially mathematical equation that tells you if-then a statement, if you will. And so that became more sophisticated with machine learning, which essentially refers to the fact that the machine can create some of those rules or learn some of those rules by itself. So, we don't need a human to explicitly program an if-then statement. But if you give enough data to a machine, especially if you provide a label, so label in this context might refer to this record is a dog that is anemic, or this record is from a dog that is not anemic, then the machine can figure out by itself the rule. And then you can take, let's say, blood work that the machine has never seen before, and you can classify it with respect to whether or not the dog is anemic, based on a rule that the machine kind of figured it out by itself.
Dr. Kent: Which may not only be the hematocrit, it may take other things into account, right?
Dr. Keller: Absolutely, yes. So, the beauty of machine learning or artificial intelligence is that you can essentially feed it as much data as you want to. And usually the more data you feed it, better and the model gets it in general. And then kind of the third level of complexity that has evolved only more recently, and I would say the last 10 years, is what's called deep learning. So deep learning is a bit of a different, we call it architecture. So basically, the computer system that lays at the base of it, it's often referred to also as neural networks, essentially. that is more complex in how it works and usually needs a lot more data. But with deep learning, essentially, what we can do is we can analyze data that is much more complicated than anything we've done before. For example, so I'm an atomic pathologist. I look through a microscope. And so at least in the olden days, and now we're switching over to using digital images instead of microscope.
Dr. Kent: So basically you photograph. the slide that you would normally look at the glass slide and digitize that.
Dr. Keller: Absolutely, that's how it works. The kind of key difference, or there's two key differences with, let's say, radiology, for example, is that pathology or histopathology requires you to zoom in quite a bit. So you could imagine looking at a world map where you can see the whole world. But then you need to be able to zoom into California and look at, let's say, the Davis city map as well, right? So, what we need are these large image files that allow you to zoom in and zoom out, which is something that radiographic images, for example, don't have that feature, right?
Dr. Kent: So there's also the 3D aspect to it too, right? I mean, almost a topographic map, because yeah, where we're sitting right now is sea level and very flat, but let's say we move over to the Sierras. the focus will be different. Do you have to take that into account as well?
Dr. Keller: Absolutely. So usually, a tissue section that we look at is 3 microns thick. And the microscope that we use to photograph that is not essentially very... There's slight variations in what we call the z-planes, or the third elevation, if you will.
Dr. Kent: Kind of up-down elevation.
Dr. Keller: Up-down correct, right? So there's some of that focus variability as well, which usually is kind of tried to account for at the scanner level, right? So the image that we receive usually has that third dimension taken out of place. For us, the third dimension is more the zoom level, how much we focus in, whether we're on the worldview versus the Davis City map. So in other words, it's a huge file that we look at, usually in the gigabytes size. And so we need a computer system that can actually handle that type of image format. And so before deep learning came around, we weren't able to really do that efficiently, or at least with kind of the tasks that we can tell it to do nowadays. And so that's been really a game changer. So looping back to your initial question.
Dr. Kent: I was about to re-ask you, let's say, you know, what's the difference when I go on and I put in a photo and I say, make a cartoon out of me.
Dr. Keller: Yes. So what?
Dr. Kent: Which I've done, by the way.
Dr. Keller: Correct. So if you look at generative AI, so if you look at ChatGPT, or things like that. They're usually now the third level that I explained, so the deep learning type of programs that require huge computational resources to do that, right? And so underlying that is what's called a neural network. And GenEI refers to generative, as the name says, so we can use it to generate text or we can use it to generate images, for example.
Dr. Kent: So now that seems almost... a waste of me using a neural network that's just been really developed to do something pretty superficial, but it can be fun. So now we've got these fun aspects, but we also have these, what people are really thinking about how AI may disrupt industries in a positive or negative sense, is these deeper machine learning things, right?
Dr. Keller: Yeah. So in veterinary medicine, there's multiple ways how we could and are integrating AI in our diagnostic workflow. For example, here at Davis, we're just now launching a scribe technology. So what that does is it essentially listens to patient Clinician conversation.
Dr. Kent: and most do you mean patient or you mean their owners? Owners, right? Yeah.
Dr. Keller: Well, these owner and clinician conversations and transcribes that and modifies that into a transcript that we can now include in our clinical record. So previously we had to take notes. We had to synthesize that into a paragraph or multiple paragraphs that makes sense. And now AI can do that for us. So the advantage of that is obviously it could be a huge save in time.
Dr. Kent: So the productivity tool.
Dr. Keller: Productivity absolutely can focus on the clinician. They don't have to write down every word. And from what I've seen, the summaries are pretty good, right? The downside of that we have to consider are multiple. So one is at this point, we have no experience how good the tool is, right? So a lot of it is probably fairly good, but without really checking that, we don't know what the accuracy or the quality is.
Dr. Kent: And that could have huge implications if we write down in the history that the dog was vomiting for three days and the computer writes it was been vomiting intermittently for three months. I'll know it was three days during my visit, but the next doctor who picks this up might be misinformed.
Dr. Keller: Absolutely. Yeah. So that.
Dr. Kent: And then what about also, so that's a little bit of an ethical issue too. Like I can't just record a phone conversation, you know, that's someone's privacy. So how do we safeguard that?
Dr. Keller: Yeah. The rules that we're setting in places that we need to have explicit owner consent to record these conversations and they're obviously not shared. They're removed after a period of time. And so we need owner consent for that. Yeah.
Dr. Kent: So is this considered generative AI if we are actually taking the inputs from what we're saying and synthesizing the conversation. It's also, I know, linked to the transcript and you can click out to fact check it. But is that considered generative AI since it's creating the summary?
Dr. Keller: Yes, it is.
Dr. Kent: Okay, so, but there's obviously machine learning or neural network behind it that's allowing it to do this synthesization.
Dr. Keller: Yes, correct.
Dr. Kent: Synthesization a word, I wonder. But we can ask AI. So where else in veterinary medicine is it being used? How is this being looked at besides the productivity tool of making it easier for me to do medical records, which, by the way, is the bane of every clinician's existence is having to sit down at night and work on your records for hours.
Dr. Keller: Yeah. So one kind of more superficial AI tool that we're trying to implement here at UC Davis is to interpret blood work. So routine blood tests that you might do if you go to your veterinarian around the corner or here at our VMTH. So things like complete blood count or chemistry panel, we can use that to check whether a dog has a certain disease, yes or no, for example. And so colleagues of mine have developed 3 classifiers. We call themselves three of these AI tools. They're able to tell whether or not a, in this case, dog has a certain disease. And so We are in the process of trying to incorporate those into our clinical workflow as well, but there's several worlds that we're trying to manage before we can do that.
Dr. Kent: But now if I'm like a halfway decent doctor and I just look at the blood work, shouldn't I be able to tell that? Do I need a computer? And you called it superficial. So is this something that's easy, well, easy to do and easy to diagnose?
Dr. Keller: Yeah, so I called it superficial because the underlying algorithm is compared to deep learning or neural networks, it would be considered superficial.
Dr. Kent: Almost an if-then statements.
Dr. Keller: Not quite. It's the machine learning level, the level 2 that we talked about before, in between, right? So we don't need as many computational resources. And it gives us a simple yes, no answer with a probability attached to it as about how certain AI is about a certain diagnosis. It spits out. So With respect to your question about shouldn't a veterinarian be able to diagnose that? Absolutely. It depends a bit on what the disease is, right? So as you know yourself, we have those types of diseases or patients that are pretty straightforward. They're slam dunk diagnoses and there's others that are more complicated. Second, We're all just humans, so we make errors. So we still train our veterinarians, our vet students to recognize and diagnose the disease. But it is nice to have a backup that in case we do have a bad day or, you know, some other things happens, we miss it. And so having a kind of backup copilot AI that will help us to not miss diseases, I think is desirable. And then third, If you're in a rush, no matter how good you are, sometimes things fall.
Dr. Kent: You would miss it.
Dr. Keller: You can miss it.
Dr. Kent: So it just will flag it for the attending veterinarians so that they can then go and check better.
Dr. Keller: Correct, yeah. So, it would run in the background and then we have a section that says machine learning algorithms or decision support tools and then at the bottom you can look at that or you can choose to ignore it if you don't want to do that.
Dr. Kent: So now, I know at least one of the diseases that's been worked on is Addison's disease, which can be really difficult to diagnose at first and can have very non-specific clinical signs, in other words, what the dog is showing to the owner. So, for this kind of disease, is this what AI is kind of made for in a sense for us?
Dr. Keller: Absolutely, yeah. Oftentimes it's used in the very initial stages to help us guide further diagnostic workup, right? So, things like Addison's disease, we would follow up with further diagnostic testing.
Dr. Kent: Yeah, and just so people understand, Addison's disease is kind of a hypoadrenocorticism. You don't have your mineralocorticoids, which are coming out of your adrenal glands and kind of balance the salts in your bloodstream, right? So you may have some very non-specific signs at first, but can be life-threatening.
Dr. Keller: Absolutely, yeah. Another one we've been working on is leptospirosis, which is a bacterial disease that affects the kidney and the liver. And those animals present usually very least fairly sick. And so it is helpful at the beginning if we know or at least have a rough idea whether or not that disease is due to a bacterial infection, like in this case, or some other causes that can cause kidney disease.
Dr. Kent: So if the computer flags it and you're still waiting for your, let's say, urine culture to come back, you may decide to go ahead and start treating it just in case because this is life-threatening.
Dr. Keller: Correct. Yeah.
Dr. Kent: And now, so I guess, what other areas in veterinary medicine am I missing any? I've heard things like there's now companies out there that are reading x-rays or radiographs, what we would call them. So images of, let's say, a dog's chest and coming up with a diagnosis with AI. So where does that integrate in? What do we need to do to make sure this is safe? How do you test these things? How do you know that the computers, you know, you've all, I think, heard the term hallucination. How do we know it's not making something up?
Dr. Keller: Yeah, that's an excellent point. And so, what we should say at the beginning is that there's no official agency that checks these types of algorithms. Like in humans, there's the FDA and every algorithm that comes out is essentially a device that has to be approved by the FDA. So, there's no quality control in veterinary medicine analog to that. And so in that regard, it is a bit of a more wild west situation. So, there are certain colleges, for example, radiology, that have proposed rules and guidelines on how to identify good or bad algorithms or at least best practices in how to develop algorithms and then disclose the details of those algorithms. But they're not legally binding. So, it basically comes down to essentially the veterinarian, if you will, to decide whether or not something is worthwhile doing or not. I mean, what we'll probably, or what we've started to see and we'll start to see is that there might be papers that check a certain, you know, algorithm to, let's say, read out x-rays. The problem with, or one thing to consider with artificial intelligence is that there's usually 2 stages. One is where we develop the algorithm. We call it training the algorithm. And then the second one is where we actually deploy it, meaning we give it something that the algorithm has never seen, like an X-ray, before, and then ask it to answer a question. And so one of the tricky things about that is that the area that you use the AI tool in has to be very similar to the conditions in which it was created, for example. In the case of histopathology, we knew that. We know that very simple things like the machine we use as scanner to take a picture of our histology slide that has a slightly different color output can vastly offset the result that the algorithm provides you with, which means that if the model was developed using scanner A and then we deployed in a clinic using scanner B, the algorithm might perform very differently, right?
Dr. Kent: It might misdiagnose.
Dr. Keller: Might misdiagnose, right? So with AI, it is really crucial to make sure that if you use an algorithm that you properly validate it, meaning you have to make sure that the algorithm performs as you would expect it in the current environment you're using it in.
Dr. Kent: So, you know, I'm... Full disclosure, I'm a member of the American College of Veterinary Radiology and I am aware of kind of the guidelines that they put forth. So let's say I was deciding to start a business and I wanted to be able to read x-rays. Can I train it off 10? How do you classify them or how do you go about building this kind of model first?
Dr. Keller: Yeah, so radiology is not my field of expertise. So, and I, even if it was, I probably wouldn't give you precise numbers as to how many cases you would need to train it. As a rule of thumb, the more subtle the pattern that you're trying to recognize, the more images or training data you need, right? In other words, if you want to train or if you meet the classifier to identify a big honking mass, that's super easy to recognize you need fewer cases to train on than if you. have very subtle differences.
Dr. Kent: But if we need all the differences you can have, let's say in a chest x-ray or thoracic radiograph, as we would say, and you want to look at the difference between, let's say, bronchitis and asthma and pneumonia and in a large lymph node or a big heart or pulmonary edema, we could have, you might need hundreds or more of really well documented or annotated radiographs to do it.
Dr. Keller: Absolutely, yes.
Dr. Kent: And then you have to test it on a different set.
Dr. Keller: Correct, yes.
Dr. Kent: And maybe radiographs taken from different machines.
Dr. Keller: Ideally, yes.
Dr. Kent: Yeah, so this can get very complex and there's not rules on how this gets done at this point is what you're saying, at least on the veterinary side. So, what about the human side? Where has this been integrated in? Are you familiar with that? Or is this something that's not your area.
Dr. Keller: I have some knowledge, but I think not enough knowledge to broadly comment on that in the podcast.
Dr. Kent: No, that's okay. That's okay. Yeah. And I've also heard people worrying about AI replacing doctors, particularly, let's say, the radiologists or pathologists, people who use pattern recognition, because really what we train our residents and our vet students to do is recognize patterns, right? You see this pattern again and again and so that this means this dog has pneumonia on the chest x-ray. This means this is a carcinoma or sarcoma on under the microscope. So where do you think we're at? Are we looking at replacing doctors at this point or, you know, do you see that happening?
Dr. Keller: Very good question. So, one of the things to note with most of the AI algorithms that we're implementing is that they're fairly narrow in scope, meaning that they are meant to diagnose disease X or distinguish between disease A and disease B, right? So it's a fairly narrow scope that if you give the AI something, let's say you wanted to diagnose or differentiate between inflammation and tumor, and then you give it a third group or type of case, it'll perform fairly poorly. So I think where humans shine at this point is that you can give me any type of biopsy. You know, it might be any disease process, most of the species, mammalian, reptile, amphibians. And I can come up with a reasonably close diagnosis. It might not be very deep with respect to, you know, brain tumor classification into like a lot of sub-entities.
Dr. Kent: It’s not you area.
Dr. Keller: Exactly. But I can make any dedicated or educated diagnosis on a broad range of different cases. Again, with AI tools, if it's not within the narrow scope that it has been trained for, it'll perform fairly poorly. So, going back to your question about replacing veterinarians with AI, at this point, I think we will use AI to look at very specific parts of our expertise and replace those, but I don't see any of us being replaced right away, right? That's one consideration. The other consideration is, again, we need to kind of figure out how good those algorithms are. And so, what we try to propagate is what's called a human in the loop, which means that the AI might initially make the diagnosis, but then we still need the human who will ultimately sign off on the case, right? Because you have responsibility for the case at the end of the day. And so, you don’t want to make it worse. Exactly that what the AI tool tells you is really correct. So there's always that consideration to it. Having said that, for radiology, I think you can already submit radiographs online. It's being read out purely by an AI algorithms where there's no true human in the loop anymore. And that is kind of a tricky thing if you can be sure that the algorithm is is really good, then maybe it'll work. But as I said before, just because there's a paper published that says the performance of this algorithm is excellent or good, it doesn't mean that in a specific, the different scenario it performs as good, essentially. So there's...
Dr. Kent: As a radiologist who's trained. So at this point, the neural networks that are out there in the computers maybe aren't as good as your neural network.
Dr. Keller: It depends. I mean, ultimately, I believe, I'm a firm believer that the machine is a better pattern recognition. And I also believe that if we get to the point where a machine is better at diagnosing the disease than me, then we shouldn't be concerned about my workplace. We should let whoever does the best diagnosis do the job. And if the machine's better than me, then, you know, we have to look at retraining pathologists to do something else. So I do believe that at this stage, I think of the game, however, we're not there yet. And we need, at least in the interim phase, also pathologists, radiologists to make sure that those algorithms actually perform the way we intend them to perform.
Dr. Kent: So I've heard the term, let's say, robotic surgery. And a friend of mine asked me when I was told them I was going to be doing this podcast, They basically said to me, so is a robot going to be doing my dog's surgery tomorrow or next year? Now, I immediately said, no. What are your thoughts on where we're headed there?
Dr. Keller: Yeah, I'm not sure about surgery. I mean, the way I understand it is price is always a big determinant, right? And so I don't know, and I know nothing about surgery where we are in that region.
Dr. Kent: In robotics.
Dr. Keller: In robotics, yeah and whatnot. I can really only speak to data that's being analyzed rather than actual mechanics involved.
Dr. Kent: So the other question I got, which I also thought was really interesting, is do you see a time when maybe instead of Google Translate, which can read anything, you'll be able to translate your dog, you know, with having the computer inputs of what your dog's looking like, maybe the sounds they're making, things like that. And getting an output that you can kind of communicate better to your dog with or understand what they're seeing.
Dr. Keller: Boy.
Dr. Kent: He's rolling his eyes on this one.
Dr. Keller: You mean with respect to just general communication or actually a pathology where we're trying to figure out what the problem is?
Dr. Kent: Maybe more just general communication there. Again, maybe this is the generative AI where we are taking a picture and making it a cartoon. But for pet owners, this might be something that would be really interesting.
Dr. Keller: Yeah, I think over time, we'll have more and more devices that measure various things. Like we all know, a lot of us wear some kind of a watch that tracks our heartbeat and whatnot. And You can do similar things now with pets.
Dr. Kent: Activity monitors.
Dr. Keller: Activity monitors, you can use the litter box to derive certain data. And so I think as these tools become more mainstream, there's going to be a lot more data to analyze. And I think it's a cool and interesting field that's really worthwhile. Having said that, some types of input might be more worthwhile than others.
Dr. Kent: Fair. So now I know you do specifically, you've been also one of the things you're working on, is trying to distinguish between inflammatory bowel disease in cats and lymphoma in cats. And I know that's really tricky sometimes, you know, for a pathologist and a clinician to figure out what the cat has. You know, both are going to cause gastrointestinal signs, diarrhea, some vomiting, and they're almost a continuation of a disease. So, what have you been doing in your lab to try to figure this problem out?
Dr. Keller: Yeah, as you see, it's a pretty tricky, tricky field. So, the basic dilemma that we have as pathologists is we get what we call the slides, so a section of tissue, and we have to look at that and these types of diseases that we talked about are essentially determined by how many lymphocytes, which is a type of a white blood cells, are present in a certain tissue section and where are they located and what is their morphology? So how big are they and what size their nucleus is and whatnot? The issue with that is that if you go back to the analogy of a world map and the city map of Davis in order to look at a lymphocyte, you have to zoom into the level of Davis, right?
Dr. Kent: And there's different types of lymphocytes.
Dr. Keller: There's different types of, yes, yeah. Light microscopically, we only distinguish, yeah, mostly one. But yeah, there's different morphologies with that, right? So what we are tasked to do as a human is essentially look at, you know, a world map and then try to figure out what is the distribution of people in continent A versus continent B or country A or city A versus B, which means We're constantly zooming in, zooming out, zooming in, zooming out, and then we're trying to summarize what we see across this world map. And as you can imagine, humans are not very good at estimating or gauging how many lymphocytes are in a specific field of view and then trying to summarize that across like a large slide like that is difficult too. So not surprisingly, if you give three different pathologists the same slide, they sometimes come up with vastly different guesses or estimates or what we call as we graded essentially. And that has led to the fact that histopathology is still kind of a gold standard, but it's not.
Dr. Kent: But it's an art also, right?
Dr. Keller: It's an art as well, depending on how experienced you are, obviously. And so what my lab is trying to do is to take the human factor out of play here. So, we trained an algorithm to recognize lymphocytes, and then we can measure how big the lymphocyte is, where it is located, how many we have. And so we get a whole bunch of data, and we just take essentially the location, the size of the different lymphocytes. And we can do that across a lot of different cases. So traditionally, if you look at studies, they might have in the two-digit max, three-digit number of cases. So what we did is we essentially went back through our archive all the way back to the 1990s and we pulled every single cat biopsy that we could find that roughly fits that entity. We came up with some literally thousands of tissue fragments and we ran it through our software and we can now determine or we can basically say what is normal, what is abnormal with respect to how many lymphocytes we have, where they are located, how big they are, and then, which is really cool, we can take these data and can put it into AI again in something we called unsupervised learning and say, okay, can you find patterns in here? So we, in other words, don't have the human expert define the pattern, but we can let the machine try to find patterns.
Dr. Kent: that we may not have seen.
Dr. Keller: That we may not have seen exactly like that. And so it's a pretty powerful tool where you can get rid of a lot of the subjectivity that humans bring into the game here. And so what we found, and we're about to publish that, is essentially their distinct kind of subgroups, subgroups with respect to how lymphocytes are organized, number, spatial distribution, but it's a continuum, right? And so it is not surprising then if you have different humans look at that, they come to different results. What the tool allows us to do now is though we can take a new case that the AI has never seen and we can classify it based on the algorithm we have. And if we repeat that 10 times, the machine will always classify it exactly the same way.
Dr. Kent: So that's consistency.
Dr. Keller: Consistency, absolutely. And so what we're trying to do now is to add outcome data to that because ultimately at the end of the day, what the pathologist calls it is not as important as to.
Dr. Kent: how this cat's doing at home.
Dr. Keller: Exactly. Does it respond to treatment? How does the cat do? How long does it survive? The tricky part with that is getting that information A&B, as you know, treatment varies, right? So cat A will get treatment A, cat 2 will get treatment B. And so getting enough data to make conclusions or predictions about how will the cat respond to a certain treatment given a certain histopathology phenotype is tricky at that point. So that's our bottleneck for sure where we need to get more data moving forward.
Dr. Kent: And that's our real bottleneck in implementing a lot of these things is having these quote unquote curated data sets where you've proven at the end what that case actually is.
Dr. Keller: Exactly. Yep.
Dr. Kent: Yeah. So what haven't I asked you that I should have asked you about AI, sir?
Dr. Keller: So personally, I find the aspect, because we are a vet school, the aspect of training veterinary students and kind of what AI effect has in our skills as diagnosticians a very interesting one. Right.
Dr. Kent: How so?
Dr. Keller: So, For example, if I know that my, AI tool will always pick up Addison's disease, or at least at a higher rate than I will, I might not look at the blood work as thoroughly again as I do right now. And as we have more and more of these tools developed, not today and not tomorrow, but, you know, a couple of decades or earlier from now, we probably have a machine that can diagnose most diseases more efficiently than humans can. And so what does that mean as a veterinarian? Do we train veterinarians as long as we're needed to keep us in, have the human in the loop? Do we relinquish certain aspects that we train? Going back to the example that we talked about before with a scribe technology. So right now, veterinarians go through a program that teaches them how to take notes and how to create a proper medical record. Now, we're introducing an itool that can do that potentially as good or better as humans do. At what point do we say we're no longer training our veterinary students to learn this skill, right? And so that now goes from a simple scribe technology to diagnosing a disease. And so ultimately,
Dr. Kent: it's a big step.
Dr. Keller: It's a big step, right? So we're opening the floodgates here where we say, okay, we might not want or need to teach that anymore. And here at the vet school, we currently don't have a real workflow decision process to deal with that, right? At what point do we say we're no longer teaching that? And our standpoint so far is..
Dr. Kent: that the human doesn't have to be in the loop anymore.
Dr. Keller: Exactly, yes. So, for the scribe technology, it appears or it looks like we're still going to require that, veterinarians have to learn the skill. But then on the other hand, it is important, I think, that the vet students learn the tools that they will encounter in practice. So, we can't just say we're not going to let them use scribe technology because once they get out into practice, they will use that and we want them to be critical users of AI technology. So they have to understand the limits and pitfalls of it.
Dr. Kent: Yeah, and I would argue, just if we're chatting about this, that when I'm teaching the vet students to take a history and do that, I'm not just they know how to type in a computer already. But what questions do you ask and how do you ask them and how do you see how the person's understanding or not so that you can get the answers that help you understand the problem as to what diagnostic tests you do. So, it's not just being a scribe. You know, that's easy. You know, they already know how to do that when they get here, but how do you actually ferret out the problem. So, we have this saying in vet med, if you hear hoofbeats think horses, not zebras, but occasionally the zebras are there. And I think so the computer probably finds the hoofbeats of horses really easily, but can it find the zebras?
Dr. Keller: Yeah, I mean, ultimately, I think it might be able to, right? now, I'm not sure. Which leads us to the next problem, I think, that I haven't touched upon, is that the validation and the ongoing monitoring of those tools. Because as we said, the environment they were trained in might be different than what we are using.
Dr. Kent: And that may shift over time.
Dr. Keller: And that may shift over time, right?
Dr. Kent: We get a new CT scanner that's got better resolution. And do we throw out all the old algorithms?
Dr. Keller: Correct.
Dr. Kent: Or do we stop learning and building new machines.
Dr. Keller: Absolutely. And so that requires a whole new compute and personnel infrastructure to be on top of that, to monitor these AI devices as we deploy them, but then also ongoing to make sure, as you said, once we get a new CT scanner, that it still works adequately. And in a kind of resource-confined environment right now with the state budget, It is hard to do that, so our IT crew is really awesome, but they have their hands full as is with just keeping the ship afloat, and so now we come in and say... hey, we have 3 new classifiers where we need to monitor how they perform and.
Dr. Kent: Integrate it into our medical record and have it notify the clinicians and don't let it hallucinate.
Dr. Keller: Exactly, all of these things. So there's essentially a whole new field that's added to IT now that they previously hadn't been doing, but they will be expected to do moving forward. And so that's certainly constrained here in my world, in my lab, has been working towards, for example, integrating these classifiers into our electronic medical record system because our IT group does not have the bandwidth to do that. But moving forward, we need more funding for these types of things if we say we're using AI.
Dr. Kent: So that's obviously going to be really important, the validation and the like. So Just to kind of wrap us up, where is all this headed? Where are we going to be in five years, 10 years? Or I know you can't predict that as you laugh when I ask the question, but what do you think?
Dr. Keller: Yeah, I mean, I'm very excited about the opportunities, but also a bit concerned about us getting complacent and not checking things as thoroughly as we should.
Dr. Kent: Shortcuts are dangerous.
Dr. Keller: Yeah, absolutely. So, I think what we should do or will do here at the vet school in Davis is to introduce things in a controlled way and test them thoroughly to make sure that our vet students still learn the skills that they need to learn, but then also become critical users of AI technology. They need to be able to use those tools and be familiar with them once they come out. So, I think we have a bit of a luxury here at the vet school in that we still, you know, can teach the old ways, diagnostic ways. I think once our graduates get out into private practice, there might be more of a pressure on them with respect to either using those tools. They obviously have to perform in very stressful situations. So, there is more of a danger, I think, of missing certain diseases and relying more on these AI tools, right?
Dr. Kent: Yeah.
Dr. Keller: So ultimately, I think it's inevitable those AI tools will be there, they will be used, they will create some damage, they will hopefully create more positive consequences than damage. But it's so difficult to predict and it's so hard to keep up with the field. It's moving at such a fast pace.
Dr. Kent: Yeah, and we can't lose the humanity of medicine either. I know we teach doctoring, you know, and you still need the person who cares. And I don't think we're there yet with computers.
Dr. Keller: Yes, and hopefully we'll never get there. We need the person.
Dr. Kent: We don't need to replace us as a race, as the human race.
Dr. Keller: Yes.
Dr. Kent: As a species, I guess, is a better way to say it.
Dr. Keller: Well, I think that most people are probably comfortable, who do want to have that human to interact with. The question is, how much does that human have to know veterinary medicine, right? Like, if you real-time transcribe our conversation, you could have also the computer put out real-time recommendations or therapy, diagnoses, things like that. So theoretically, I think I can imagine a world where you still have the human interface, but that human doesn't understand a lot about veterinary medicine like in the far future.
Dr. Kent: I hope that we're far away off from that because it just... It just seems to me we'll lose that caring aspect, at least at this point.
Dr. Keller: Yeah.
Dr. Kent: Well, Stefen, Dr. Keller, thanks so much for joining me today on The Vetrospective. It's been a very enlightening conversation and hopefully not a cautionary tale, but a way moving forward to make sure that we're not giving up too much on veterinary medicine.
Dr. Keller: Thank you for having me.
Dr. Kent: Of course.
The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E06: Dog Genetics
- Read the Transcript
- Dr. Bannasch: So we understand the genes and the alleles that give different coat colors in dogs, and in fact, blue versus brown eyes in dogs and other traits. We also understand many of the alleles that give and cause diseases in dogs, and that's what I've been working on for 25 years and a lot of other dog geneticists around the world.
Dr. Kent: Hello, and welcome to the Vetrospective. This is your host, Dr. Michael Kent. I'm a professor in radiation oncology at the UC Davis School of Veterinary Medicine and your host. Today, we'll be talking about dogs and genes.
A, T, C, G. These are the letters that make up the “Code of Life”, the instruction manual that is the guide our cells use to build each of us and pretty much most life that we know. The bases put into different combinations are the building blocks for genes. Genes, in turn, are the blueprint of life, and our understanding of them is helping shape the future of diseases and medicine. As dogs evolved from their ancestor, the wolf, becoming domesticated and really co-evolving with us, we created breeds. This was done by selectively breeding dogs for the traits that allowed us to coexist in the same environment and take on the many roles dogs play in our lives. Whether it's working dogs, sporting and hunting dogs, or dogs that have been bred to be our companions, genetics is at the heart of it. IT gave us breeds diverse as Chihuahuas, pugs, Labs, golden retrievers, and even the really large Great Dane. Unfortunately, in creating these breeds, we inadvertently also bred in characteristics we did not want, those that can lead to certain diseases.
Today's guest is Dr. Danika Bannasch, a veterinary geneticist here at UC Davis, who will help us better, really, get a better understanding of the ins and outs of this complex, but really cool and interesting topic. Dr. Bannasch received her undergraduate degree in genetics from UC Davis. and then went on to do her PhD in molecular biology from Princeton University before returning to UC Davis for her veterinary degree, a postdoc position, and a residency in genetics. Then she became faculty. She has run an active genetics laboratory for over 25 years here and has published over 140 scientific papers and is now Associate Dean for Research here at the Vet School. Welcome to the Vetrospective, Dr. Bannasch. Thank you for joining me here today.
Dr. Bannasch: Thank you for having me.
Dr. Kent: No, it's great. I appreciate it. So first, I want to ask you a question I ask most of my guests. How did you decide to pursue a career in veterinary medicine and why genetics in particular?
Dr. Bannasch: So, I actually always wanted to be a dog geneticist. I just didn't know how to do that because there weren't really any dog geneticists.
Dr. Kent: Was this at 5 years old? You knew the word genetics or geneticists? So tell me a little more.
Dr. Bannasch: I wrote in my high school yearbook that I wanted to study animal genetics. So, I had figured it out by then that it was kind of the science behind dog breeding, and I think that's where it came from. When I was 12 years old, I did some dog walking for some neighbors and friends of ours, and they took me to the Philadelphia Dog Show. So that was the first dog show I went to, and they gave me the AKC dog breed book. And I went through and just marveled at all of the different sizes and shapes and colors of dog breeds and got really fascinated by that and wanted to study why that happens. So yeah, I mean, I don't like to tell the students about my history because people don't usually know what they want to do when they're 16 years old.
Dr. Kent: I did not.
Dr. Bannasch: It is highly unusual, but I guess I'm pretty focused.
Dr. Kent: No, that's good. So each of our cells have genes in them, right? They're in the nucleus and they're organized into chromosomes. I think most people have heard of that. But how does that translate into actually making a dog?
Dr. Bannasch: So, the genes are sort of a blueprint for proteins, and it's actually the proteins in the body and the proteins that are made that come together to give different cell types. So your bone cells are different than your skin cells, for example. And then all of those different cell types go and turn into organs, and the organs work together to make a dog or a human.
Dr. Kent: Pretty much any species. So now you get one set of genes from each parent, right? And they mix up a bit.
Dr. Bannasch: They do. There's some shuffling in both of the parents so that the offspring actually have a sort of slightly different complement of, it's not genes, but versions of genes. So we all have the same genes. In fact, humans and dogs have pretty much the same genes. There's just the sequence of the genes is a little bit different.
Dr. Kent: Okay, so the gene kind of codes for an idea of what a liver should do, but maybe a dog has a variation on it compared to a human.
Dr. Bannasch: Right.
Dr. Kent: And within dogs, there could be variation as well.
Dr. Bannasch: Right. Less variation than there is between dogs and humans, but yeah, there's variation between dogs. Same as there's variation between humans.
Dr. Kent: So in a sense, the genes are a code book for us, right? And to understand how we're built and each cell is regulated.
Dr. Bannasch: Yep, I mean, people use the term colloquially now and say like, oh, my DNA or my blueprint, right? And they're sort of synonymous.
Dr. Kent: So if we want to get down to seeing my blueprint, we're talking about sequencing. And this is the process of getting the genetic information out of a cell. Do we just take a cell or a group of cells and put it in a machine? Is And just kind of in that, we could talk about what kind of sample do we use? Because I know you're not either spitting or cheek swabs or a blood sample. Is there advantage over one over the other?
Dr. Bannasch: So we can sequence DNA from lots of different sources. So you can get DNA from a cheek swab, you can get DNA from blood, you can get DNA from a tissue sample. And the difference is really in the quality and the amount of DNA that you can extract out. So, for modern sequencing techniques, cheek swabs will work, but blood is probably a little bit better because you get enough extra in case something happens.
Dr. Kent: So, you get more DNA than you do off a cheek swab.
Dr. Bannasch: Yeah. And you asked about the sequencing process. Things have changed in the last 20 years or so, sequencing is very efficient and not very expensive. So we can sequence the whole genome of a dog for about $500.
Dr. Kent: What did that cost before? Like to sequence the first dog or do we even know that?
Dr. Bannasch: Yeah, I mean, it's definitely gone down drastically and the Human Genome Project cost billions of dollars.
Dr. Kent: And that was for the first one person.
Dr. Bannasch: Yeah. So that sequencing is a little bit different. So we talk, we'll go back to dogs for a second. There's something called a genome assembly. And that is the sequence of a dog put together into chromosomes, and we use that as sort of a benchmark. So currently, we use the genome assembly of a German shepherd named Mishka. And that's the one that most dog geneticists would align to. So if I wanted to sequence the DNA of a patient in the hospital because it has a disease that I think is inherited, I sequence that DNA and we do that by chopping the DNA up into little tiny bits and sequencing the little tiny bits. And then you have to align those little tiny bits to a genome assembly. So in this case, we align to Mishka, the German Shepherd, And then we use bioinformatics tools to identify the differences between my patient and Mishira.
Dr. Kent: Okay, I'm going to stop you just here for a second. And bioinformatics tools, it's kind of this black box. So you wind up with all these little sequences that you have and a big Excel sheet, let's say, that's just got.
Dr. Bannasch: There not on an Excel sheet.
Dr. Kent: Yeah, so it's huge, right? So what is bioinformatics and how do you kind of use that?
Dr. Bannasch: So bioinformatics is basically the application of computer science to biology. So in this case, you know, you said at the beginning, there's just four base pairs, right? And it's just the order of those four base pairs on each chromosome, that's what matters. Or in the case of sequencing a patient, it's just the differences between that dog and all of the rest of the dogs that matter. So bioinformatics is the ability to be able to pull out those differences and maybe gets them to a form where you can look on an Excel file, but technically, each patient that we sequence has maybe 6 million variants compared to Mishka, the genome assembly. So you can't even open that in an Excel file.
Dr. Kent: Yeah, that's a big file. So obviously we need bioinformatics and software to help us sort all this out. So, what is normal? You said we're using Mishka, one dog, one German shepherd. Why don't we go back to the wolf as the gold standard since this is where dogs came from? Or how do we know a gene has changed? And not just a variation on normal, because I know if you sequence me and you, we're going to have some pretty big differences there.
Dr. Bannasch: Yeah, we will. There were a lot of questions there.
Dr. Kent: I know, sorry.
Dr. Bannasch: So there's a number of genome assemblies available now. For a long time, we had one, which was Tasha the Boxer. And then Mishka came about, and that was an improvement in that there was more sequence put together than in Tasha. So we switched to Mishka. I will say there is actually really a good Greenland wolf assembly. So sometimes we use the wolf. It's not just about how good the assembly is, it's also how good the annotation is. So…
Dr. Kent: What do you mean by annotation?
Dr. Bannasch: So most of the genome doesn't code for genes, the protein coding genes. And those are the ones that we know the most about. So the genome assembly that we use is the one that has the most information about the protein coding genes, because those are the ones we look at first. So I told you, I gave you an example that I sequence a patient's DNA. The very first thing I do is look for changes in the protein coding sequence to see if there's something that might be causing their disease there
Dr. Kent: And that's called exons, right?
Dr. Bannasch: Yeah.
Dr. Kent: Now, when I was in school forever ago, they called the rest of it junk DNA. And I know it's not junk DNA. So what are those other portions of the DNA doing that aren't just making our proteins?
Dr. Bannasch: So there's a large amount of the genome that's repetitive DNA. About 40% of the dog genome is repetitive DNA. About just a couple percentage codes for proteins. And the rest, we're not quite sure what it does yet, but I think we're starting to realize that it probably does something and that we shouldn't just ignore it.
Dr. Kent: Interesting. So, like I said in the intro, we bred dogs initially from wolves. How closely related are dogs back to the prototypic wolf?
Dr. Bannasch: We estimate that domestication occurred somewhere between 10,000 and 25,000 years ago. And you can certainly tell by DNA that an animal is a wolf versus a dog. There are enough differences there that we can tell that. But between dogs, there aren't that many differences. So you can look at a compilation of things of DNA sequences to try and tell breeds apart. But they're not as different as you might think.
Dr. Kent: So how different are dog breeds? are they related to each other very closely or?
Dr. Bannasch: So it doesn't take many variants to sort of change a French Bulldog from a wolf.
Dr. Kent: Interesting.
Dr. Bannasch: There's variants that would make it smaller. There's variants that would make it brachycephalic. So in other words, not having a muzzle. There's variants that would make its tail kinked. But it, and there's probably variants that are affecting the coat color that change it. But it's really, you know, a dozen or so. It's not a huge number. And so there's not that many variants that differentiate the different dog breeds from each other.
Dr. Kent: So the blueprints are, for each dog breed are pretty similar in just small number of changes in certain genes.
Dr. Bannasch: Right, and then there's also some changes in frequency of alleles so that you can identify by the DNA that it belongs to a certain breed, but those aren't changes that are changing proteins.
Dr. Kent: So what do you mean by frequency of alleles? I know I'm asking a lot of basic questions that someone who knows genetics should know already, but please.
Dr. Bannasch: No, so we talked about genes because that's a term that's familiar to people, but really the genes are all the same. So you and I have the same genes, all the dogs have the same genes. The differences are sequences that we call alleles, which are basically the different versions of the gene that exist.
Dr. Kent: What gives me dark hair and you brown hair?
Dr. Bannasch: Right, exactly. Although hair color is a little bit complicated in people. It's a little bit simpler in dogs. But yeah, there's just a couple.
Dr. Kent: Okay, eye color, is that more simple? No, of course not. I couldn't come up with a good analogy for you.
Dr. Bannasch: But it is straightforward or more straightforward in dogs. So we understand the genes and the alleles that give different coat colors in dogs and in fact, blue versus brown eyes in dogs and other traits. We also understand many of the alleles that give and cause diseases in dogs, and that's what I've been working on for 25 years and a lot of other dog geneticists around the world.
Dr. Kent: And why I have you sitting here today. So basically, these alleles are different to create different individuals. And it's this combination of all the different alleles of your genes that make me, and you, you.
Dr. Bannasch: Yup.
Dr. Kent: Now, I know there's this term kind of called genetic diversity. And in dogs, it's, I've seen some controversies about whether we bottleneck dogs and, what I kind of made an idea is, are dogs less genetically diverse than, let's say, cats or people?
Dr. Bannasch: Well, they're definitely less genetically diverse than people. Within dog breeds, the inbreeding is actually quite high. Part of that is due to how dog breeds were initially created. So someone had a dog that they liked and they started breeding more dogs that were similar and the quickest way to get dogs that were similar would be to breed relatives to each other.
Dr. Kent: Line breeding, it's called, right?
Dr. Bannasch: Well, initially it might have even been inbreeding to get a dog. So I see on your computer you have a sticker of a golden retriever. I think you might be sort of fond of golden retrievers. Golden retrievers started from one particular male stud dog who was bred to a number of different females and the entire breed was created from them.
Dr. Kent: From one dog.
Dr. Bannasch: Well, from a handful of dogs.
Dr. Kent: Yeah.
Dr. Bannasch: And then once there were sort of typical looking dogs of breeds, the kennel clubs were organized and started and started limiting the individuals that could be registered as that breed. And so once you sort of close off the gene pool and don't allow any new dogs to enter, then you're sort of forcing continued inbreeding. And what we end up with today are most dog breeds that have really, really high inbreeding and no sort of avenue to add additional genetic material. So like the purebred dogs, you can't go out and bring in another unrelated dog.
Dr. Kent: So, I know there's tests that you can order now that you can cheek swab or get saliva from your dog, and you can take a mixed breed dog and it'll tell you where they came from. Is it Golden Retriever? Is it a Goldendoodle? Is it a 10% this breed and 20% that breed? Are these tests getting better? Are they good now? Do you think it provides information?
Dr. Bannasch: Yeah, they're actually pretty good. And I think people are really interested in what their mix might be and what sort of combination of breeds it might be. I think it can give people some information about expectations about how big that dog might be or what it will be like. And in addition to telling what mixes a dog is, a lot of these panel tests will also test for potentially inherited diseases. So, each particular breed might have four or five tests for inherited diseases for that breed. And if your dog is a mix of a couple of different breeds, then you can find out about those inherited diseases that those breeds may have.
Dr. Kent: So they would run specific tests based on what breeds they have found your dog to be and get like a golden retriever panel and a Labrador panel or?
Dr. Bannasch: No, the companies that run tests that will tell you what breeds your dogs are, run a panel of health tests, and they always run the same panel. So there are other companies that have put together specific panels for breeds, and they don't all necessarily run the same tests.
Dr. Kent: And when you get, let's say, a positive result, now, does that mean that dog's going to develop the disease in its lifetime? Is this something maybe you don't want to know?
Dr. Bannasch: I would assume that the information would be helpful for their health care. So it depends on what the mode of inheritance is. If it's a recessive trait and your dog just has one copy of it, then it will normally be fine. If it's a recessive trait and they have two copies of it, then you need to worry about that disease and talk to your veterinarian about what the results are so that the veterinarian can guide the health care of the animal.
Dr. Kent: So Danika or Dr. Banish, I'm basically a cancer guy, right? And I'm mostly clinician. I like to do some other things. So I'm going to ask you some basic question there. So what's the difference between the genes that are passed on and let's say the genetic changes we see in a cancer cell?
Dr. Bannasch: Yeah, so it's one of the things I teach the first year vet students is the difference between those. So the genes that you pass on are exactly that. The allele, the bad allele, is passed on through the eggs and the sperm and can go to the next generation. That's really different than the mutations that occur that cause cancer. Those mutations accumulate in a cell, let's say a bone cell, and when enough mutations accumulate and mutations in cancer-causing genes, then that cell gets transformed into a cancerous cell, which grows and makes a tumor and makes cancer. So those aren't necessarily passed on, although there are inherited cancers where a predisposition to having cancer can be passed on.
Dr. Kent: Yeah, that's obviously a lot of more work needs to be done in that area. And I wanted to go back to coat color a second. So you had said that we've kind of figured out coat color in individual breeds a lot in the dog. And has coat selecting for coat color led to disease? If we are selecting for one thing, often you pull unrelated genes along, that might lead to disease.
Dr. Bannasch: So there are definitely some coat colors that have some bad things associated with them. One in dogs, and a couple in other species in horses and cats. But the one that comes to mind right away in dogs is merle coat color. So merle is that variegated gray, if it's on a black background, gray spots that you can see. And if dogs have particular alleles at that gene, and the dog has two copies of them, sometimes they can be born deaf or blind. And so this is a case where the variant associated with the change in pigment also affects hearing and development of the eye.
Dr. Kent: So this is just kind of one disease. So while coat color is pretty interesting, it's just a small piece of the overall puzzle of looking at disease and looking at breeds and if there's breed predilection for disease.
Dr. Bannasch: Yeah, and most of the time the coat color isn't associated with problems. It's just something that people have preferences for.
Dr. Kent: So about how many genetic diseases in the dog have we identified and can we test for now? Do you have any idea of that? I know it's a big broad question.
Dr. Bannasch: Yeah, we're quite a few. I think we're up to about four or 500.
Dr. Bannasch: That is a lot.
Dr. Kent: Yeah. And how does that compare to, let's say, people? Do you know, are there multiple diseases also that have been identified in humans? Or I know you're not a human geneticist.
Dr. Bannasch: I'm not a human geneticist. I think that, you know, there's a lot more that's been done in people. And we do things a little bit differently in people. So we routinely would sequence people to try and identify what variants they might have. The interesting thing is that people aren't inbred. So they don't all have the same variant in a gene that causes the disease. They will have different variants. But in the purebred dogs, we always are looking for just, I mean, rarely is there more than one variant in a gene that causes the same disease.
Dr. Kent: So the alleles, which are going to vary across individuals, sometimes they're good, or you could have multiple good alleles, and occasionally one of those alleles might actually lead to a disease.
Dr. Bannasch: Yeah.
Dr. Kent: Okay. So, over the years I've worked here, I've heard some really great work that has come into your lab. And I think the first one I heard was, the first one I heard of was about Dalmatian dogs, particularly male Dalmatian dogs. So I know Dalmatian dogs carry a genetic variant that leads to hyperuricemia or hyperuricemia, right? And where they excrete high levels of uric acid into their urine. which makes stones that accumulate in the bladder. And if they accumulate in the bladder, they can try to urinate them out through their urethra or the tube that goes from your bladder to the outside and they get stuck. And this would make male Dalmatians in particular, you know, if they get stuck, then your bladder gets bigger and bigger and eventually ruptures and is fatal. So can you talk to me a little bit about this story and kind of talk to our listeners about it, because it's a really cool story.
Dr. Bannasch: Yeah, it's a really neat story. I used to have Dalmatians. They were my favorite breed. And we had a urologist here who was a professor of mine, Dr. Ling.
Dr. Kent: I remember him.
Dr. Bannasch: Who encouraged me to try and figure out, you know, why Dalmatians have this hyperuricosuria. And this was a really long time ago. So before any whole genome sequencing could be done in dogs, before the genome assemblies were made. And we were really fortunate that a dog slash mouse geneticist did a cross. So he crossed a Dalmatian to a pointer, and then he back crossed to Dalmatians. And each generation, he selected for low uric acid. And so this cross was actually done in the 1970s, and I had always known about it. And for a long time, it was really just one person who was doing this cross. And some Dalmatian breeders in California decided that they also wanted to participate in the cross and try and get rid of the bad allele of this gene.
Dr. Kent: So, they were still maintaining a Dalmatian in a sense, but they were breeding in another breed to fix this problem.
Dr. Bannasch: They just did one cross to a pointer and they were taking the normal allele and each generation they were selecting for the normal allele as they crossed to Dalmatians.
Dr. Kent: But they couldn't read the gene yet. So they were just finding the dog who didn't make the increased uric acid in the urine and then breeding them back in.
Dr. Bannasch: And anyone who has Dalmatians. purebred Dalmatians that don't have the normal gene. It's really fun. You can take Dalmatian urine and put it in the fridge and it'll turn to sand. So it's pretty easy to phenotype them. And he also did some special testing of the urine, but nonetheless, he did this for 14 generations. And then Denise Powell, who was a breeder in California, decided that this was something she was really passionate about. And she started breeding these low uric acid dogs and allowing us to collect samples from the dogs, including urine and a little DNA sample. And we use that information to identify the region of the chromosome where the gene was located, and then eventually the gene and eventually the mutation. So nowadays, I could do that project in, oh, I don't know, a couple of hours. But…
Dr. Kent: So a different approach.
Dr. Bannasch: But the project at the time took my graduate students a couple of years, but eventually we did find the gene and the mutation. Once we had the mutation, we confirmed that all Dalmatians had the mutation, unless they were crossed with pointers. And eventually the Dalmatian Club of America and the American Kennel Club allowed those dogs to be registered. So now you can actually get a Dalmatian that doesn't make bladder stones, which is pretty exciting.
Dr. Kent: That's huge, right? So you breed out the problem then?
Dr. Bannasch: Right, so you can breed out the problem. The other thing that we found out about this mutation is that, well, it was known to be in Dalmatians. We also had reports of it being in Bulldogs and Jack Russell Terriers and Weimaraners and black Russian Terriers. But as these testing companies that test more and more dogs, it turns out that it's the 4th most common mutation in all dogs that are tested. And so Knowing what the gene is and the mutation is actually helpful for all dog breeds because there are other dog breeds that have this. They just don't have it as commonly as the Dalmatian did.
Dr. Kent: So a breeder could go get these tests done of their dogs that they're going to breed and hopefully try to avoid that and breed out disease.
Dr. Bannasch: Yep.
Dr. Kent: That's really cool. So is it unusual that one gene causes a problem or some diseases caused by multiple genes of their interactions? So are there risks if we fix one problem that we create another, a kind of genetic whack-a-mole almost.
Dr. Bannasch: It shouldn't be. There was definitely concern when we started offering genetic tests to dog breeders that this could cause rises in allele frequencies of other bad alleles. But as long as breeders, even though the dogs are inbred and there isn't much you can do about that now, you can continue to try and breed relatively unrelated animals to each other and do testing each generation. So while you're eliminating 1 allele, you shouldn't necessarily have this sort of sweep.
Dr. Kent: A knock-off effect. So these tests can be really useful in saving a breed. I was just wanted to kind of wrap things up and ask you, where do you see things going? What is the, what do you look for in the future of genetics in dog breeds and genetics in veterinary medicine?
Dr. Bannasch: I think we've gotten really good at solving the simple Mendelian traits, so traits where it's just one gene involved. And I think the future is going to be tackling some of the more challenging questions in dog health. And so that's cancer, autoimmune, and inflammatory diseases, and the one that we really haven't solved, which is epilepsy. So all three of those diseases are definitely not one gene. There might be some examples of some severe disorders that are caused by one gene.
Dr. Kent: In a small number of dogs.
Dr. Bannasch: Yeah, small number of docs, but idiopathic epilepsy is not understood at the genetic level, and yet dogs like to have seizures, for example. And the same thing with cancer. There have been some alleles identified that seem to carry a higher risk of cancer, but they don't explain the risks of breeds that have high cancer rates. So, I think settling those more complex diseases is what we're going to see next. And I think that's really exciting.
Dr. Kent: This is really exciting. And I really enjoyed speaking with you about this today. I'd really love to have you back so we can talk about more examples of genetic diseases. There's just so much that we've learned and so much more that we need to learn. So, thank you again, Dr. Banas, for joining us today.
Dr. Bannasch: Thanks for having me.
Dr. Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E05: Cancer Immunotherapy
Dr. Kent and Dr. Rachel Brady speak about how cancer immunotherapy works and where it’s headed.
- Read the Transcript
- Dr. Brady: We are looking at the gaps of where we still need to do better, and immunotherapy can help kind of fill in some of those gaps for some patients. and that's life-changing for the patients that it does help. And for the other patients, we have to keep working.
Dr. Kent: Hello, and welcome to today's episode of The Vetrospective, where we dive into all aspects of health and wellness for dogs, cats, and other companion animals. This is your host, Dr. Michael Kent.
Immunotherapy has emerged as a whole new type of cancer treatment. Traditionally, we've used surgery, chemotherapy, and radiation therapy to treat cancer. More recently, we've added targeted therapies. These are drugs that target pathways that turn on, really and get stuck and drive a cancer cell to reproduce. In both human and veterinary oncology, we now have the emergence of immunotherapy. Some early work was done in the late 19th century with something called Cooley's toxins, but these were not consistently doing and can cause a lot of toxicity. So this was before we even had an understanding of how the immune system works. Now, as we are really beginning to understand the cells of the immune system and how they interact with cancer, there are new treatments and even preventatives emerging. So today I have asked Dr. Rachel Brady to join us to talk about immunotherapy for cancer treatment.
So Dr. Brady has an undergraduate degree in philosophy and then went on to do her veterinary degree here at UC Davis. She did her rotating small animal internship at North Carolina State and then her residency in oncology back here at UC Davis. So I've known her for a while. After finishing her residency, she then left and went to Colorado State to do her PhD in cancer biology, where she studied macrophages. We'll talk a little bit more about that later. I'm glad to say that Dr. Brady is now my colleague again. She was hired on at UC Davis as an assistant professor in oncology. So welcome, Dr. Brady. It's a pleasure to have you here today.
Dr. Brady: Hi, thank you so much for having me. I'm really happy to be here today.
Dr. Kent: And thank you for agreeing to do this. So I always like to ask people this, what got you interested in veterinary medicine and why specifically cancer? Why oncology?
Dr. Brady: When I was a little girl, my grandmother gave me all of the James Herriot books. I don't know how many of our listeners will know those books, but they were a series of mostly true books written by a veterinarian under a pen name. And I just thought they were the coolest thing ever. He got to travel around, meet all different animals, help all different animals, but also really helped people as well.
Dr. Kent: All Creatures Great and Small. I read those too.
Dr. Brady: So that, I really feel like I credit that with putting me on the path towards veterinary medicine.
Dr. Kent: So you knew from a really young age?
Dr. Brady: I did. I took a bit of a winding path, but I ended up here, yes.
Dr. Kent: And why cancer?
Dr. Brady: I didn't know I was interested in cancer until my last year of veterinary school, which is kind of called your clinical year, where you're actually in the hospital learning how to treat patients. And I realized how impactful the cancer cases are. Not only to the animal, but almost any person you meet has a story of having cancer or knowing someone with cancer, And that really kind of got me interested in how much work there is to do in that field and how much potential there is to help.
Dr. Kent: That's cool. Mine's a little similar. We'll talk about that maybe some other day. So maybe to start out, cancer is a very, you know, big term. Can you try to define for me or tell me, what is cancer.
Dr. Brady: Yeah, I'm glad you asked that because I think to understand how immunotherapy works, it is important to understand how cancer evolves in the body. And so if you think of a normal adult human or adult dog, we have trillions of cells in our bodies. And each cell has DNA in it, which you can just think of as a recipe, but it has billions of letters making up this recipe.
Dr. Kent: It's a complex recipe.
Dr. Brady: It is. So if you think of that, we have trillions of cells with billions of letters inside of them. And every time a cell needs to duplicate or make another cell of itself, it has to copy all of those letters perfectly. And so I bring that up to say, over a lifetime, there's going to be mistakes made.
Dr. Kent: It's like typing, right? If you're typing and you're just typing words from another paper, you should see my autocorrect, right? It's not good.
Dr. Brady: And so even though our body has evolved ways to correct those mistakes or avoid those mistakes, it's inevitable that mistakes will happen. And when enough of those mistakes accumulate at a certain point, that we call that cell cancerous.
Dr. Kent: Okay, and then that cell divides and that leads down the road to having a mass we can find and then, and the like so.
Dr. Brady: Right.
Dr. Kent: What I was also saying now as we go here, kind of the big question. So why doesn't the immune system just kill this cancer cell like we would any virus, bacteria, or other infection that we're faced with every day, we have thousands of bacteria or viruses around us.
Dr. Brady: Right. And that is the big question that everyone's trying to figure out.
Dr. Kent: That's why I asked you.
Dr. Brady: But so I think to understand that, we need to understand how our immune system works. Our immune system is made-up of cells we call white blood cells, and their job is to keep our body in homeostasis.
Dr. Kent: Okay, homeostasis, what do you mean?
Dr. Brady: A state of balance.
Dr. Kent: Okay.
Dr. Brady: We can't have too much of any one thing. So when anything disturbs that balance, as you mentioned, an injury, an infection, with a bacteria or a virus, it's those white blood cells that identify that and respond to it. I like this metaphor that I've been told, I did not come up with this myself. You can think of all these white blood cells as having satellites on them. We call them receptors, but they're basically the same thing as a satellite sticking out from the cell. And they're constantly patrolling the body for anything that disturbs this balance. And when they sense something, they start sending signals, just like a satellite sends signals down a big cable. They send big signals inside the cell, which then tells other cells that something is going on. And these cells need to react to fix the problem.
Dr. Kent: Okay, yeah. So we're trying to fix this problem here. And so why don't they with cancer cells?
Dr. Brady: So what happens with cancer is two different things. First is, as we already mentioned, these cancer cells are actually our own cells that have small mistakes in them. And for some cancer cells, our immune cells just literally cannot recognize that they are something that's disturbing the balance because they're not so foreign as a virus or a bacteria that's invaded your body.
Dr. Kent: So it's your cell that's changed. So, the immune system says, oh, That's your cell, so it doesn't attack it.
Dr. Brady: Right.
Dr. Kent: Yeah.
Dr. Brady: The other main thing that happens is that unfortunately, the cancer cells can be very smart, that they have evolved ways to basically build a brick wall around this mass or this tumor that's growing and basically hide it from the immune system. So even if our immune cells could try to recognize them, they're often blocked from doing that because the cancer has outsmarted them.
Dr. Kent: So there's this concept of immune editing. I'm wondering if you could explain it better for me and for everyone who's listening.
Dr. Brady: Right, so immunoediting is broadly the process by which these cancer cells escape our immune system. So as I said, all of these white blood cells are constantly on alert for anything abnormal in the body. So there's an early phase when cells with these mistakes, maybe we'd call them pre-cancerous or a very early cancerous cell, that our immune system is recognizing them and eliminating them. And that's happening in all of us all the time.
Dr. Kent: Every day.
Dr. Brady: Every day. There's a second phase where it becomes more in equilibrium. Maybe a small tumor has grown, but the immune system is still able to keep it in check. So the immune system and the cancer cells are in an equilibrium state then where not one of them is winning?
Dr. Kent: Kind of like a chronic infection in a way.
Dr. Brady: Exactly. And at that point, usually none of us know that a tumor is there. That's usually before we're able to detect it on most of our tests. And then the third step is unfortunately what we call immune escape, where the cancer cells have evolved enough of these mechanisms to outsmart the immune cells and build up that brick wall. and it kind of tips that balance over into letting the tumor grow, what we call in an uncontrollable fashion. And that's really the hallmark of cancer by definition, that it has escaped the ability of our immune system to control it.
Dr. Kent: So this is almost Darwinian in the evil kind of way that basically it's survival of the fittest cancer cell.
Dr. Brady: Exactly.
Dr. Kent: Yeah, that's very cool. So when we're talking about these walls and like, are we looking at basically immunosuppression.
Dr. Brady: Yes.
Dr. Kent: And are we looking at it in the tumor or your whole body? Are you immunosuppressed?
Dr. Brady: Yeah, that's a great question. So, once a tumor has grown to that stage where it's escaped our immune system and this is the time that we can start picking it up or it might start causing symptoms, it has developed its own environment, like its own little ecosystem. And in that ecosystem, it is there's a ton of immunosuppression. So it is keeping out the white blood cells that we would want to be in there to kill off the abnormal cells and which we can talk more about later, it is recruiting our body's own immune cells to actually help it to grow. So it's almost flipped these cells that are supposed to be helping us to the bad side.
Dr. Kent: And I always also like to just think of it in terms of… so we almost need autoimmune disease to kill those tumors. So they're using that side, that balance of the immune system that's keeping us from attacking our own body, but amplifying it?
Dr. Brady: Yeah, exactly. And you can almost think of autoimmune diseases as the flip side, where we mentioned before a body needs to be in balance. And autoimmune disease is where the immune system is way ramped up and attacking itself. Whereas cancer is, you're absolutely right, it's stopped attacking itself when we would want it to.
Dr. Kent: Yeah. So Can you tell me what are the main types of immunotherapy that we use to try to treat and maybe just keep in mind how we're trying to change that environment? I know this is an area you do research in.
Dr. Brady: Yes, definitely. So, as we've learned more about these immune cells and our immune system in the past couple of decades, we have realized that we can try to convince the body's immune cells that it should be fighting these cancer cells. And there's two main ways you can do that. One is to try to damage that brick wall. I've mentioned a couple ways. So you can knock it down in different ways or weaken it.
Dr. Kent: So this brick wall that's kind of isolating the tumor and keeping it immunosuppressed.
Dr. Brady: Correct. And a very popular example of doing that is our checkpoint inhibitors, which some people may be familiar with. But all that a checkpoint inhibitor does is stops the cancer from being able to build up that brick wall. It's removing its ability to do that so then our immune cells can flood in and start killing those cancer cells.
Dr. Kent: So this is kind of like inhibiting the immunosuppression?
Dr. Brady: Exactly.
Dr. Kent: Okay, taking off that brake that's stuck on, that's keeping the cancer basically protected.
Dr. Brady: Yes, it's inhibiting the inhibitor. And this has been life-changing for people with melanoma or some types of metastatic lung cancer. It has literally turned fatal cancers into ones that can be cured or controlled really long-term.
Dr. Kent: So I interrupted you. said there was two types.
Dr. Brady: Yeah, so the other way that people try to approach this is rather than weakening this metaphorical brick wall is just to overwhelm it. So to really strengthen our immune response to the point that this brick wall doesn't even matter. We're just, we have so much of an immune response, it can flood in there anyway. And so some examples of that are things like cancer vaccines, which is not a vaccine how a lot of people think of it.
Dr. Kent: So do you mean like a preventative vaccine? Or more of a treatment vaccine?
Dr. Brady: More of a treatment vaccine in this case, where we are trying to help our immune cells know which cells to attack. So a normal vaccine might tell your cells, hey, these proteins look like they come from the flu. If you see these flu proteins in your body, you need to attack them. We can do the same thing, but with pieces of the cancer.
Dr. Kent: Great. So basically, instead of me going to get my flu vaccine every fall, you might, would it be your own cancer cells that would use to do this or more of a generic vaccine like you get at a pharmacy?
Dr. Brady: People have tried both approaches. It is trending more towards personalizing these vaccines for an individual tumor. Another really popular strategy that some people might have heard of for this idea of just kind of strengthening the immune response so much that it overwhelms the immunosuppression are CAR T-cells. This is one of the earliest immunotherapies to be incredibly successful. And this is when we...
Dr. Kent: And it's in people still at this point.
Dr. Brady: This is in people, although there's several early trials in dogs as well.
Dr. Kent: And can you tell me what is a CAR T-cell? Because that's, you know, it's a little complex, right?
Dr. Brady: To answer that, Just to define a T cell first is we've been referring to the immune system as white blood cells. Very generally, though, those white blood cells are split into two groups. There's the initial kind of guards that we call the innate immune system. And those cells are able to recognize a virus or a bacteria or maybe those early cancer cells right away and kind of stimulate a fast response, but it's a very non-specific response. It can kind of try to wipe out anything, but it's not targeted against a specific virus or a specific bacteria.
Dr. Kent: Okay.
Dr. Brady: But then what it does is also signal to the body that we need to mount up this secondary set of defenders, and this is called the adaptive immune system.
Dr. Kent: And that's what we vaccinate with, or that's the response we're trying to get.
Dr. Brady: Exactly. So one of those cells that's very important is the T-cell. It's a white blood cell. That's main job is to kill cells that shouldn't be there. So when we say a CAR T-cell, that fancy word in front, the CAR, it's an acronym. just for chimeric antigen receptor, which that's not important. The important part to know is that we take a person's or a dog's own T-cells out of their body. We modify them in the laboratory and tell it, hey, you need to be looking out for this particular type of cancer cell. And then we put them back in the body in huge numbers, hoping that they will attack the cancer cells.
Dr. Kent: So basically you just reprogram them so that they find the target that you wanted to, in this case, the cancer.
Dr. Brady: Exactly. And CAR T-cells have been life-changing for people with different lymphomas and leukemias. And those are cancers that we call kind of blood-borne, that are mostly found in your blood. And they have changed certain types of lymphomas from, again, fatal into being able to be cured.
Dr. Kent: So you've been talking about some of these as advances in humans. And I know we're a bit behind, but can you explain to me or tell me a little bit about how similar our immune systems are between, let's say, a dog or cat and a person? And can we just use an immunotherapy made for people? So can I take one of the treatments and put it right into a dog or a cat?
Dr. Brady: Yes, great question. Because obviously I'm a veterinarian and my passion is helping animals.
Dr. Kent: Mine too.
Dr. Brady: But as I've mentioned, I really love the opportunity to also help people. And that is the really cool thing that dogs and people and cats actually develop very similar cancers. So it's not perfect, they're different species, but a lot of the tumors that they develop are similar enough that breakthroughs that we find in a dog can be applied to a human and vice versa.
Dr. Kent: Yeah.
Dr. Brady: It's not perfect. Immune systems are complex.
Dr. Kent: So are our immune systems similar?
Dr. Brady: More similar than a lot of the animal models that have to be used. So anytime a new immunotherapy or any drug for that matter is going to be given to people, it has to be shown to be safe. And that has been historically done in mice. Mice have very different immune systems from people. So while dogs and cats are not perfect replicas of the human immune system, they're a lot closer to us than mice.
Dr. Kent: I like to think of myself more like a dog than a mouse.
Dr. Brady: Yeah, me too. And it is, it really does go both ways. We can really help all of those species by collaborating with our colleagues who treat people. Breakthroughs that they've had can help us treat dogs and cats and other animals better and vice versa. And that is one thing I really love about what we do.
Dr. Kent: It's pretty neat. So one of the areas that has been a huge breakthrough, for example, in lymphoma in people is something called the monoclonal antibody.
Dr. Brady: Yes.
Dr. Kent: I was hoping you could kind of maybe break that down for me, explain what it is, and then kind of, you know, we'll go from there.
Dr. Brady: Yeah, that is another big area of research in immunotherapy. So antibodies in general are a protein made by another immune cell in our body. And they are an important way of also killing off things that shouldn't be there.
Dr. Kent: So like a bacterial infection or something like that?
Dr. Brady: Exactly. Some of our immune cells will produce massive amounts of antibodies that in a bunch of different ways can kill off those bacteria cells.
Dr. Kent: Bacteria, viruses, et cetera.
Dr. Brady: Exactly.
Dr. Kent: So how are we trying to use them for cancer?
Dr. Brady: So you can, in a lab, make these antibodies that target the proteins that a cancer cell puts out. So basically everything in our body, everything that we're talking about, it revolves around proteins. Proteins are the things that we can tell these cells to find and locate.
Dr. Kent: There are building blocks, right? Proteins make up everything in us.
Dr. Brady: Exactly.
Dr. Kent: So are there enough differences between a cancer cell with a protein in a normal cell with a protein, are you just going to make one of these really bad autoimmune diseases we were just alluding to earlier?
Dr. Brady: Sometimes.
Dr. Kent: Yeah.
Dr. Brady: Not all the time, but some specific types of tumors have enough of these mistakes that we've talked about, that they're making proteins that are very, very different from normal proteins in our body.
Dr. Kent: And we can target those. Great.
Dr. Brady: Some tumors, we're not as lucky and we have to use other approaches.
Dr. Kent: So can I take, there's a lot of monoclonals available for people now. You see them advertised on TV all the time.
Dr. Brady: Yes.
Dr. Kent: And they all end in MAB, right? And they're using them not only for cancer, but I've seen an ad for eczema and other things as well. So can we just take those and use them in our patients now? Can I use it in one of my dogs or cats? I know that's a loaded question.
Dr. Brady: No, that is a good point because that would be awesome if we could. But unfortunately, what happens if you take one of these antibodies targeted towards something in the human body and put it in a dog body, the dog's immune system is going to say, whoa, there is something foreign here. It's going to know that protein doesn't belong there and attack it or make other antibodies to attack it, just like it would any other foreign invader. So what we need to do is make the proteins, make these antibodies very similar to the natural antibodies a dog's body might make or a cat's body might make. However, it's still very helpful. We can still use a lot of the foundational work, but we have to just make it specific to a dog's body or a cat's body.
Dr. Kent: Are some tumors more likely to respond to immunotherapies than others?
Dr. Brady: Yeah, this is an interesting question. It has become more normal to talk about some tumors in the immunotherapy world as hot or cold.
Dr. Kent: And what do you mean by hot or cold? What's a hot tumor?
Dr. Brady: So a hot tumor has a lot of these proteins that are really different and that we could really attack well. While a cold tumor, you can think of it, we say cold, but you can think of it as, yeah, this kind of bleak winter landscape just without a lot of things going on that we can really target with our immunotherapies.
Dr. Kent: So, give me an example of a hot tumor.
Dr. Brady: In people and in some versions of the dog tumor, melanomas are what we consider a hot tumor. And that means as they've been replicating, as they've been like making new cells, and all these mistakes are accumulating, they are very, very different from a normal cell. And so it is much easier to target that with some of these things we've been talking about.
Dr. Kent: So that's why it's the prototypic, you know, poster child for immunotherapy in some ways and some of the big advances have been made. So can you give me an example of a cold tumor that we see in vet med?
Dr. Brady: Yeah, unfortunately in both, children and in dogs, there's a type of tumor called osteosarcoma that grows in the bone. And unfortunately, it does affect younger children. And that tumor is kind of known for being very cold, where it's been proven very hard to target with immunotherapies, because there's not a lot of things for our immune cells to latch onto on it.
Dr. Kent: So I told everyone earlier that you like to study macrophages. At least you did your PhD in it. So first, what's a macrophage? That's besides something with a cool name.
Dr. Brady: Yeah, I've been waiting for this. I've spent the past four years talking about these cells. So we did briefly mention these two different arms of our immune system where we have that initial wave, the innate immune system, and then that second wave that's a little bit later, the adaptive immune system.
Dr. Kent: That initial assault to try to knock something out.
Dr. Brady: Right. Most of the immunotherapy work so far has been on T-cells, which are part of that second later wave of our immune system. But more recently, in the past decade or so, we've become interested in these cells that are part of that innate wave. So innate meaning they're the first responders, sometimes within hours of some type of insult, of an injury or an infection. One of those cells is called a macrophage. A macrophage are these big cells that their main job is to eat other things in the body.
Dr. Kent: They kind of clean up the mess, right?
Dr. Brady: That's right. They can clean up viruses, bacteria. They can clean up our own cells that are dead or diseased. And we can convince them to sometimes eat up the tumor cells.
Dr. Kent: So how do we do that? Well, that's the million-dollar question, right?
Dr. Brady: That's right. So, one thing that cancer does, as we've mentioned before, but really particularly with macrophages, is it convinces macrophages to support it. So, part of that brick wall I've mentioned, that is chock full of macrophages that are defending the tumor from other immune cells from coming in. And they are directly kind of helping the tumor grow. So, what we needed to figure out is how do we convince them to to get back on the good side.
Dr. Kent: We have to reprogram, get them out of the cult.
Dr. Brady: Absolutely. And we call that re-educating or repolarizing them. There's many different ways to do that, but the main goal is to remind the macrophages, hey, you're actually supposed to be fighting against these cancer cells instead of defending them. And the cool thing is that the macrophage-based therapies are not really meant to be used alone. What they're meant to do is be used in conjunction with some of these long-standing therapies at work, like checkpoint inhibitors, and they make each other more effective. So think of this, you know, this brick wall surrounding the tumor, and you're weakening it at certain points with these checkpoint inhibitors. But if you can also then change a bunch of the macrophages in that brick wall and say, okay, you also attacked the tumor. You've weakened it in more than one way. So really, when you can use these therapies together, they tend to be synergistic.
Dr. Kent: This is great. Now, I'm going to pretend to be a cynic, which I'm not. I'm an oncologist, so therefore I'm an optimist. But over my career, I've seen cancer cured many, many times in the headlines. And then we come back to the reality of what it can do. So, these immunotherapies that are emerging, they're not all here yet for us. But where does this fit in? How do we integrate it into our practice? How do we bring these therapies forward? How do we know if they work?
Dr. Brady: Right. That's a good point because obviously I'm passionate about this and I'm painting this awesome picture, which is really, there is a lot of room for hope or a lot of reason to hope. But like anything, it's not perfect. We don't have a precise controller of our immune system. So, there's still side effects to these therapies and there's still a lot of patients who maybe respond to them for a short time and then the tumor starts to grow again or don't respond at all or have such bad side effects they can't continue on with the treatment. And so I know a lot of people always ask me, you know, why don't we have a cure for cancer yet?
Dr. Kent: Yeah.
Dr. Brady: And it's because every single tumor that grows is different. So we're not trying to cure cancer. We're trying to, you know.
Dr. Kent: Cure a million different diseases.
Dr. Brady: Exactly, as they keep popping up. And so what I think is, this is not going to wipe cancer out, but what we are looking at the gaps of where we still need to do better. And immunotherapy can help kind of fill in some of those gaps for some patients. And that's life-changing for the patients that it does help. And for the other patients, we have to keep working.
Dr. Kent: And how do we work? How do we figure that out? How do we know if it works or not?
Dr. Brady: Yeah, so one thing that you and I are both involved in are...
Dr. Kent: Softball question, I know.
Dr. Brady: Clinical trials, which is really important because we want to, in a scientific way, show that these therapies are safe and then show that they are effective. So, both in people and in dogs and in cats, we run these very controlled trials, where we enroll, let's say dogs with a specific tumor type, give them a specific treatment and very rigorously kind of follow how they do. And it's cool here at UC Davis, some of the people here made our own checkpoint inhibitor that you were involved with.
Dr. Kent: Yes.
Dr. Brady: And that's a huge deal for us because that's been used routinely in people for decades now, and so we need to really work to catch up to that. And we're giving it to dogs now with diseases that are considered very end stage and would be, these cancers would be killing these dogs within a short period of time.
Dr. Kent: And we've had our first dog actually clear its lung tumors, which is pretty amazing.
Dr. Brady: It is amazing.
Dr. Kent: Yeah, so this is a lot of hope and a lot of promise. I mean, that's what we need in oncology, right?
Dr. Brady: Yes, absolutely.
Dr. Kent: So I'm gonna wrap it up here and just wanted to say thank you for taking the time to speak with me. It's been a pleasure, Dr. Brady.
Dr. Brady: Oh yeah, thank you for having me. I hope it was useful to everyone who's listening.
Dr. Kent: I hope so too. You know, I think immunotherapy is just this black box right now, and I hope kind of our deep dive into how it works will be helpful in understanding that.
Dr. Brady: Yes, absolutely.
Dr. Kent: All right, thanks.
Dr. Brady: Thank you.
Dr. Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E04: Cat Food
Dr Michael Kent speaks with UC Davis' Dr. Jennifer A. Larsen to talk pet food nutrition again —this time for our Cats! House panthers, little lions — what should they eat? What can't they eat? What if they are exceptional hunters? Get the facts behind the fancy marketing headlines...
- Read the Transcript
- Dr. Larsen: Which is kind of fascinating for an animal that evolved with a pretty strict diet of prey, that they could be so metabolically flexible. It's really interesting.
Dr. Kent: Well, I'm not surprised if any species could be flexible, it would be a cat, right?
Hello, and welcome to today's episode of Vetrospective. This is Dr. Michael Kent, professor and radiation oncologist at the UC Davis School of Veterinary Medicine, and your host. In a previous episode, I had Dr. Jennifer Larsen on to talk about dog food, how to pick, you know, what to feed your dog. It was a great discussion, and I know I learned a lot. So, well, in addition to my dog and fish, I have two cats at home. And I thought it'd be great to have her back to talk about feeding cats, because we all know cats are not dogs. Dr. Larsen, Welcome back to our show.
Dr. Larsen: Thanks so much. It's great to be back.
Dr. Kent: Thank you. So just to recap for those of you not listening to the Feeding Your Dog episode, Dr. Larsen is a clinical professor in nutrition here at the UC Davis School of Veterinary Medicine. She's a board-certified specialist in nutrition and runs an amino acid laboratory here at the school besides being head of our clinical nutrition service. So maybe I'll ask you this first. Nutritionally, Why are cats not like dogs?
Dr. Larsen: Well, cats are special and for a lot of reasons.
Dr. Kent: I was going to say, I know that.
Dr. Larsen: But most notably, because they evolved as little carnivores. And that's in contrast to dogs, which essentially evolved as scavengers, essentially. they live sort of in approximation with human habitations, et cetera. Cats evolved as carnivores and they eat small prey. So they never really had the selection pressure during evolution to build the pathways to make certain nutrients in their bodies. So it's really important that we meet their protein requirements and we make sure that they're getting all the nutrients that they need.
Dr. Kent: So let me go back to that a little bit. Most people have learned or think of dogs as carnivores.
Dr. Larsen: Yeah, so taxonomically they're carnivores.
Dr. Kent: Yeah, but what about nutritionally? So how is their selective pressure? Have we changed them from wolves? Are wolves carnivores nutritionally.
Dr. Larsen: Yes, we've absolutely changed dogs. That's part of the domestication process, which is a biological process that has genetic implications that influence everything from the reproductive behavior of dogs, their affiliative behavior with wanting to live with people, their ability to help us with things like herding sheep instead of catching, killing, and eating them. And that influences their nutrition, of course, as well.
Dr. Kent: So what about with cats? I'd like to think that my cats want to live with me as much as, I know my dog does, I think my cats do. So how has that difference in their jobs changed and come out nutritionally as well?
Dr. Larsen: Yeah, that's a great question. And cats have also been domesticated, but the process hasn't been going on for as long as it has for dogs. And cats have a little bit different jobs. They're really important companions and pets for us, of course, but we haven't sort of made cats that will help us with hunting and retrieving things that we hunt and helping us on farms and those kinds of things.
Dr. Kent: Unless we think of them as like mousers or barn cats.
Dr. Larsen: Absolutely. Cats kind of have the same jobs, right? And cats are also not as diverse among cats as dogs are. So for dogs, we have a huge size diversity and job diversity and personality diversity between a Chihuahua and a Great Dane, for example. Cats are pretty much, or at least much more similar in body size and behavior compared to dogs.
Dr. Kent: So when I think of cats and I think of dogs, dogs are most of the time going to be eating, out of the dog food, right, that we provide them, whether that's home cooked, whether that's commercial. But cats now, especially if they're outdoor, indoor, outdoor, sometimes are kind of supplementing their nutrition. They may be eating mice, they may be unfortunately eating birds. How does that affect, when we're thinking about their nutritional requirements, how does that affect that?
Dr. Larsen: A lot of cats still engage in hunting behavior. And even for an indoor-only cat, sometimes they're going to be eating little insects in your house or at least killing them.
Dr. Kent: Yeah, mine seem to catch bugs every once in a while.
Dr. Larsen: And that's very fun for them. When a bug gets in the house, it's very exciting because that kind of behavior is very self-rewarding to an animal that evolved that way. And then I think a lot of people have also had the experience of their cats leaving them portions or whole bodies on their doorstep.
Dr. Kent: Presents.
Dr. Larsen: Presents.
Dr. Kent: Doorstep. Hopefully not your bed.
Dr. Larsen: Yes. Which apparently means that they just think we are terrible hunters and they're trying to make sure that we survive with their gifts, which is kind of sweet.
Dr. Kent: I, yeah, I'm a terrible hunter and I'm not going to eat half the mouse, though. Sorry. You know, that goes beyond my dietary.
Dr. Larsen: You have a line.
Dr. Kent: Yeah. I have a line. I have many lines. So I know that cats can't make certain amino acids like taurine. Can you go through kind of why an amino acid is important and why, you know, they have these nutritional requirements as kind of a species in a sense?
Dr. Larsen: Yeah, cats do require specific nutrients and they're really sort of well known for their higher than average protein requirements, especially compared to dogs and compared to people. And that's partly because of their evolution as a carnivore and the way that their sort of metabolic machinery works is that they need a constant supply of nitrogen and they need to have a constant supply of certain essential amino acids that are really important for a wide range of functions in their body. And as I had sort of alluded to before, they didn't evolve the ability to make those things because they didn't have the pressure evolutionarily to develop those metabolic pathways because those things were always plentiful in the prey that they were consuming.
Dr. Kent: Okay, and specifically, maybe you can tell us about the taurine story with cats. You know, being a requirement and first not being in foods and then being added.
Dr. Larsen: Yeah, taurine is really interesting. And cats' metabolic pathways, I mean, they're very interesting metabolically. They're very...
Dr. Kent: Cats are really interesting so it makes sense.
Dr. Larsen: They really very much are. So cats actually have all of the enzymes and metabolic pathways in order to make taurine.
Dr. Kent: Okay.
Dr. Larsen: But because of the activities of the different enzymes in those pathways and then the alternate pathways, most of the precursor is instead pushed down another metabolic pathway. So they actually don't make taurine to meet their metabolic needs.
Dr. Kent: So it's kind of like having all the faucets turned on in your house and you're not getting water to the bathroom.
Dr. Larsen: Yes, exactly. That's a good analogy.
Dr. Kent: Okay. And we need the taurine. Why?
Dr. Larsen: So taurine is an amino acid. And I think most people have sort of heard the expression that amino acids are the building blocks of protein. And while that's true, taurine is a special amino acid because it's actually not used to make protein. It's always available sort of in its free form. And taurine is really important because it's a small molecule that's important for normal calcium signaling within cells. And muscle cells in particular rely a lot on calcium signaling, especially in the heart. And so taurine deficiency has a lot of different symptoms, including things like poor reproductive performance or degeneration of the retina that's in the back of the eye and cats can become blind. But one of the more devastating symptoms that we see with taurine deficiency involves the heart muscle. So the clinical syndrome is referred to as dilated cardiomyopathy or DCM. And that just means that the heart muscle gets kind of thinned out and Heart is kind of big and baggy compared to normal muscular. Yeah, it doesn't really pump the blood the way that it's supposed to.
Dr. Kent: Yeah. And are there other examples of nutrients that cats are really dependent on that maybe we don't think of as much for dogs, for people even?
Dr. Larsen: Yeah, vitamin A is another good example. So for us and for dogs and some other species, we can eat beta-carotene and other carotenoid compounds, which are essentially just plant pigments. I think most people are aware that colorful vegetables like carrots and sweet potatoes contain beta-carotene. That's what makes them orange.
Dr. Kent: And yummy.
Dr. Larsen: And yummy. And they can use beta carotene in order to use that as a source of vitamin A. Cats can't do that though. And again, they have the enzymes available to do that, but most of the precursors are going to be going somewhere else. So cats really need to eat vitamin A as a preformed form of vitamin A.
Dr. Kent: So are there certain kinds of food that we would feed a cat that could lead to making sure they get all these nutrients or could lead to deficiencies.
Dr. Larsen: That's a good question. I think that some cats could potentially be fed dog food, and that's inappropriate because they have distinct differences in terms of their nutritional needs compared to dogs. So while dogs can survive and thrive on cat food, the reverse is not true. Cats should not be fed dog food.
Dr. Kent: Oh, my cat occasionally grabs one of my dog's kibble, which I'm shocked that he lets her do.
Dr. Larsen: The forbidden fruit, they can't resist.
Dr. Kent: Yeah. So if we're thinking then about generally what kind of food to feed, do you find that more people want to home cook for their cats or is that less common?
Dr. Larsen: I think it's highly variable. By far, probably kibble dry food, dry commercial food is still the most common way to feed both cats and dogs. That's the most economically viable way for most people. It's also a way to meet all of their nutritional needs in a very shelf stable way that is safe and has been effective for a long period of time. There are some people that are interested in feeding diets that are raw, so either frozen or freeze-dried raw. Canned food is quite popular as well. And some people do want to cook for their cats.
Dr. Kent: So a couple of questions following up on that. Can I just feed them like salmon or canned salmon or canned tuna or other fish I get at the, you know, at the grocery? Cats love fish, or at least we all think that.
Dr. Larsen: Yeah, those kinds of foods are fine as a treat, but if you wanted to feed that as the sole diet, it's really important that it's balanced. So cats require about 40-ish essential nutrients, and it's really important that those are all present in the diet in adequate amounts and appropriate ratios.
Dr. Kent: Okay, so if we are going to be feeding canned as their main source, we shouldn't just go get a can of tuna fish and feed that.
Dr. Larsen: Yeah, you should really make sure that you look at the label and it should be pet food that says that it's complete and balanced for the life stage that your cat is in. So if you have a growing kitten.
Dr. Kent: Just like dogs we talked about.
Dr. Larsen: Yep, life stage appropriate balanced diets are important. They have a much shorter lifespan than us. Unfortunately. And so it's really important that they have a balanced diet. We can get away with feeding, with eating an unbalanced diet for much longer than a dog or cat, just based on the scale of their lifespan.
Dr. Kent: And then we were talking about different forms of food. So wet or dry, what's the advantages of each? What's the disadvantages?
Dr. Larsen: So as I mentioned, kibble is going to be the most cost-effective option by far. And partly that's related to calorie density. So canned food is going to be usually three to four times less calorie dense than dry food. Now, that might be an advantage if you have a cat that has a big appetite, because obesity is a huge problem in cats, no pun intended. And obesity has a lot of negative health consequences. And we really want to make sure, ideally, that obesity or unwanted weight gain is prevented. But if it does happen, reversing it is really, really difficult because cats become very thrifty with their calories. And we often need to pretty severely restrict them, which is unpleasant for everybody.
Dr. Kent: I'm going to talk to you a little bit about that later, but I wanted to ask you first, What about semi-moist foods?
Dr. Larsen: Those used to be pretty popular. Currently, probably the most popular form of feeding semi-moist is going to be from treats. So semi-moist are sort of the sort of squishy textured treats.
Dr. Kent: Yeah, not quite dry, not quite wet.
Dr. Larsen: Yeah, pets find those delicious. They like the texture and the flavor of those. They can dry out pretty quickly, and it's not going to be as cost-effective as kibble.
Dr. Kent: So you mentioned earlier also about, raw diets, but are most cat foods carbohydrate free or some carbohydrate free since they're more protein? And I know that's been a fad, at least for dog foods. Has that come up in the cat world?
Dr. Larsen: That has come up a lot in the cat world. People have a lot of concerns about carbohydrates. First of all, we don't have any carbohydrates that have been determined to be nutritionally essential. And the term carbohydrates, just to be clear, that encompasses both indigestible carbohydrates, which would be fiber. And fiber is a really important nutrient, still not essential, but is really important for normal gut health.
Dr. Kent: Just like us.
Dr. Larsen: Yeah, of course. And it's not considered essential for people either, even though...
Dr. Kent: Oh, I thought it was.
Dr. Larsen: We're continually told to eat more fiber. And then digestible carbohydrates would be things like starches and sugars. Now, of course, sugars aren't going to be present in the diets of cats, and they don't tolerate a lot of simple sugars in their diets, as you would expect. But they actually can digest and absorb starch quite well. And there doesn't seem to be any negative health effects related to that. In fact, cats can adjust their metabolism depending on where most of their calories are coming from, either fats or proteins or carbohydrates. They change what they're oxidizing for energy. So, which is kind of fascinating for an animal that evolved with a pretty strict diet of prey, that they can be so metabolically flexible. It's really interesting.
Dr. Kent: Well, I'm not surprised if any species could be flexible, it would be a cat, right? But now, I know certain times you have to restrict things like protein in a cat. Let's say they have renal disease. so how do we go about still making it palatable? I know, like, you know, my Labrador, I think he'd eat anything we let him. Cats, not so much.
Dr. Larsen: Yeah, cats do have a reputation for being picky or selective. Really that relates to their nature as being essentially neophobic, which means that they have a little bit of a suspicion of things that are new. And so we always recommend that when people have kittens or young cats, that they make sure that they expose their cat to a wider range of flavors and textures. Cats generally sort of rely on learning that from their mom and their litter mates because what they consider to be a safe something to eat is going to be informed by the other animals around them eating those things. And so it's really not that uncommon for a cat to only be fed one form of food or one flavor of food, and then they become quite fixated on that and they really won't be very adventurous in trying other things. So it's really important that we address that problem. And then if we have to modify the diet to address a certain disease.
Dr. Kent: Yeah.
Dr. Larsen: So kidney disease is very common, especially in senior cats, and more and more of our cats are living longer and longer, which is fantastic. We really have to make sure that we are assessing the current diet and what that cat is used to. We also have to look at what the diet looks like in that individual cat, because if you had 10 cats with kidney disease, they're all going to have pretty individual needs. So how advanced it is?
Dr. Kent: Nutritionally and medically.
Dr. Larsen: Yes, of course. Yeah. So that customized individualized approach applies to both the medical management and the nutritional management of that disease.
Dr. Kent: And that's where a veterinary nutritionist comes in.
Dr. Larsen: Yeah, and we leverage fat a lot in those cases because cats do find protein to be very tasty, but fat is really tasty too. And so we can leverage fat not just because it gives us more calories per gram than we get from carbohydrates or from protein, but because it's also palatable. So those diets for kidney disease are often pretty robust in their fat content.
Dr. Kent: And what do you think about nutritionally? I know I've talked to some owners and their cats have stopped eating because of one disease or another, and they are on a special diet. And then I mean, my advice has always been calories first. You know if it comes to that. As A nutritionist, what do you think?
Dr. Larsen: That's a really common challenge. There are lots of diseases that will impact appetite, and there's some treatments and medications that are needed that will also impact appetite. And so, Sometimes we are using different ways to sort of encourage adequate intake of an appropriate diet. Sometimes that might mean making sure the diet is warmed up, maybe changing the moisture content with warm water or a little bit of broth. Sometimes we recommend changing the site that the animal is fed or the kinds of bowls that are being used. Cats in particular have strong opinions about where they're fed and how they're fed. So for example, a very narrow, high-walled bowl is not going to be very liked by a lot of cats. They don't like smashing their whiskers into a bowl like that.
Dr. Kent: They're more sensitive.
Dr. Larsen: Yeah, a flat, wide container is a much better way to feed the cat. And so trying to do the sort of that troubleshooting process in terms of can we manage some things about the diet that are making the pet not feel well, like maybe they're dehydrated or they're anemic, and we can address that medically. And then sort of addressing some of the feeding management things. And then finally, we can make some modifications to the diet itself in terms of adding the warm water. Maybe we add some tasty toppers and those kinds of tricks that we have.
Dr. Kent: Yeah, I've always been amazed at how quick cat food will heat up in the microwave. It's like 5 seconds and you don't want to burn their mouths. You have to be really careful.
Dr. Larsen: Yeah. It's really important that we make sure we don't have hot spots and those kinds of things. Sometimes I'll recommend people use a warm water bath instead of the microwave just to avoid that. We really don't want to burn their little mouths.
Dr. Kent: No, that would be quite bad. So now as we talk, the other flip side of this is the obese cat that you brought up earlier. So How do you manage that? How do we approach this, especially, a single cat household, but then I want you to talk about multi-cat household too.
Dr. Larsen: Yeah, obesity in cats is really common, which is very frustrating. And it happens for lots of different reasons. There's certain risk factors. Some of them are human related and some of them are cat related. And so what I mean by that is that a lot more people are keeping their cats inside more because there's lots of dangers.
Dr. Kent: My cats are indoor.
Dr. Larsen: Yeah.
Dr. Kent: You know.
Dr. Larsen: There's cars, there's coyotes, there's other cats and dogs, infectious diseases.
Dr. Kent: Hawks.
Dr. Larsen: Yes.
Dr. Kent: You know, yeah, it's dangerous world out there.
Dr. Larsen: But we're not, we're getting better, but we're not doing a perfect job with the enrichment of keeping their brains healthy. And that in turn affects their body being healthy. The things that they have to look forward is interactions with you, laying in the sun in front of the window and feeding time, really.
Dr. Kent: Yeah, the laser pointer helps a bit too sometimes, right?
Dr. Larsen: Engaging them in chasing things around, maybe throwing toys, Sometimes even have people throw individual treats or kibble down the stairs or down the hallway, because cats really like that chase activity. It's very enriching for them. Some people will even have cat running wheels, kind of like we use sometimes for hamsters and such, but they're cast signs. They're wonderful.
Dr. Kent: For the right cat, right?
Dr. Larsen: Well, on the right house. Not everybody can fit that in their apartment, right?
Dr. Kent: Fair.
Dr. Larsen: Other things that would potentially increase the risk of unwanted weight gain is the neutering process. Now making sure that cats are spayed and neutered is something that we've been advocating in veterinary medicine for a long period of time. There's certainly downsides to humans living with both intact females and intact males.
Dr. Kent: When we first adopted our cats, who recently were neutered. We dealt with a lot of those issues.
Dr. Larsen: Yeah. Cat urine has a distinct odor that is much stronger when they are not neutered.
Dr. Kent: It does.
Dr. Larsen: And so neutering definitely has impacts on food intake. And then eventually will have impacts on energy expenditure as weight gain results from that food intake. And dude, from research that has been done on this campus, we know that increased food intake happens very soon, within a couple of days of the neutering procedure. Cats will voluntarily start eating more. So it's really important that owners are aware of that, after a neutering procedure, that they might have to, and for a lot of cats, decrease the amounts that they were feeding. Some of the other human factors might be that a lot of people assume that free feeding their cats is the way that it should go. And a lot of cats do graze throughout the day. And that's sort of the natural pattern of how cats eat.
Dr. Kent: How my cats eat.
Dr. Larsen: But a lot of cats can't handle that without becoming overweight. And so we still have to make sure that we're feeding them a limited amount throughout the day, even if we're giving it in multiple small meals per day.
Dr. Kent: So what kind of strategies do you use, let's say, if you have one really skinny cat who grazes and you have one maybe chunky kitty like I have.
Dr. Larsen: That's a very common problem. And a lot of times we can use technology to help us. We do have some microchip-enabled feeders that are quite popular and that work quite well in those instances. Sometimes they're little bowls that have like a lid that opens and closes in response to the microchip that the cat has, but you can also use a collar with a microchip in it if your cat is not microchipped. There's also the sort of cat doors. And you can use those cat doors to separate feedings as well. So instead of having a microchip operating feeder, you can have a cat door either like in a storage bin or maybe a door in your house while only one cat has access to a guest room or a bathroom or something like that. Or you can go the low-tech, low-cost way of just simply teaching your cats how to meal feed and using a bathroom or a bedroom to keep one of the cats in just during the feeding time and then open the door and everybody has free range the rest of the time when food's not available. It does take a little bit of effort one way or the other.
Dr. Kent: I did want to jump back, because this is just how my brain works, to one of these fad diets. And I've heard of people feeding their cats vegetarian and trying to. And I get it. If you're a vegetarian, you might really not like the smell of meat or you may not morally want it in your house. Is that possible with a cat or can you talk to me a little bit about what's out there and what's available?
Dr. Larsen: That's a really good question. We do sometimes have clients that are interested in feeding their cats vegetarian diets. And there are commercial diets that are available that are marketed as cat foods. One of my previous veterinary residents did a study looking at this. This was a study that was funded by the Center for Companion Animal Health.
Dr. Kent: I do know that being its director. So, yes.
Dr. Larsen: And Dr. Kanakuba was very interested in veterinary approaches to feeding and vegetarian diets specifically. And so what we did in that study was we collected all of the vegetarian diets that we could find in the market at that time, and we ended up with 24 diets. Some of them were canine diets, some of them were feline diets, and some of them were marketed for both dogs and cats. And what we did in that study was we looked at the labels and made sure that it had a complete and balanced claim for whatever species it was intended to support. And then we looked at the ingredient lists and whether there were amino acid supplements in there and so forth. Then we took a sample of each of those diets and we analyzed them for the amino acid profile. And what we found was that all of the diets that were marketed for cats or for dogs and cats, did not meet the amino acid requirements for cats.
Dr. Kent: So what would that mean?
Dr. Larsen: Well, that would mean that potentially over the short or long term, depending on how severe the deficiency was, you would expect to see some clinical signs associated with that deficiency. And we only looked at amino acids. We didn't look at all of the 40 essential nutrients, which would include vitamins and minerals. And we had some concerns about those diets and the overall nutritional adequacy. So based on what we found in that study, we don't recommend any vegetarian diets for cats.
Dr. Kent: So just jumping back to labels, since you just mentioned them, and this just came into my mind. And when we were talking last time, we were talking about dog food labels and are they the same as cat food labels as far as what's reported? Is there anything specific we should be looking for on a cat food label or maybe even just to recap a little bit what you want to look for on a label?
Dr. Larsen: Yeah, dogs and cats diets are going to be regulated the exact same way. So at the state level and at the federal level, the same kind of ingredients are allowed and not allowed. the same kind of things have to be included on the label. So one of the most important parts of the label is often overlooked. People sort of inappropriately focus on things like the ingredient list, which really isn't that informative. What we really want to look for is the nutritional adequacy statement, sometimes referred to as the AFCO statement or the intended use statement. And basically that tells you whether the diet has a complete and balanced claim, And if it does, how the claim was substantiated, and that's either going to be by formulation and comparing the profile of the diet to the nutrient profiles for pet food. And it also tells you the species and life stage that the diet is intended to support. So that's going to be important if you had a growing kitten, for example, you want to make sure that you're feeding a growth appropriate diet.
Dr. Kent: Yeah, that makes sense. So maybe it's my perception, but it seems that cats are less marketed to than dogs in a sense. Like we talked last episode about how there's a lot of marketing claims made for dogs and that often come out as nutritional fads per se. And do you think that's the case for cats that there's less of it or am I just not noticing the advertising?
Dr. Larsen: I think that it's shifting. Over the last few years, we have seen a shift from the pet population moving towards smaller dogs and cats. And more and more people are living in smaller places potentially, or they want a pet that's a little more manageable or maybe more portable, or maybe they're living in apartments and those kinds of things. And there's a lot more people living in cities than in suburban areas and rurally probably. So there's definitely a shift. The pet food industry is making more diets in smaller packages, for example.
Dr. Kent: For dogs and cats.
Dr. Larsen: For dogs and cats. Yeah. And there are people that still want to, you know, get Costco sized. packages of food and so forth. But there's definitely a shift. And I think that, I think the industry in general and veterinary medicine specifically is pretty done with ignoring cats. We still need a lot more research data to support some of the medical treatments and nutritional strategies for cats. They've been historically neglected in terms of the data that we have. But in terms of products and marketing, I think we're really moving into a more cat-centric and well-deserved sort of attention on them.
Dr. Kent: So the attention could have a flip side too, and I'm going to be a little provocative here, so please bear with me. You know, we're talking about pet food companies, right? I know that many of them support the vet school and nutrition programs not only here, but elsewhere. So does this bias your teaching, your research, what you train people on? Just, if I wanted to put it crudely, I'd say, Are you in their pocket? You know, and don't take this wrong. I mean, you know, I think it's important that we talk about this stuff.
Dr. Larsen: That's an excellent topic. I think that's something that there should be a lot of transparency around. The pet food industry and the companies that make pet products, they're really important partners for us in veterinary medicine. and they're really not separate. A lot of our colleagues work for those companies and so forth.
Dr. Kent: They employ nutritionists.
Dr. Larsen: Of course, yes. They employ nutritionists. They employ veterinary medicine specialists and food safety experts and toxicologists, et cetera, agriculture people. And we've had close relationships with several different companies over the sort of lifespan of the veterinary school. They're really important in terms of supporting our educational missions and our clinical missions. They help us improve patient care. They help us improve education of veterinary specialists and of our students. They do give us grants, so their financial support is really important. And of course, also people that are specialists like myself, sometimes we do speaking at veterinary conferences on behalf of pet food companies that will, you know, arrange it and pay an honorarium, et cetera. And different people might have different experiences, but I can tell you that I have done that multiple times. I have never had a pet food company ask to review and change my slides or tell me what to say in terms of recommending diets or anything like that. In fact, I've had a couple of them tell me, please don't mention brands at all. It's just a disease management talk, which I understand, but most practitioners want some practical advice and they want to know exactly what to feed. So that makes it really challenging. And there's often going to be more than one product that's going to meet the needs of a specific company.
Dr. Kent: So what about the grants? Do they give you a grant and you do specific research for them? Or is it, does it direct what research you do? Like, I just want to make sure we explore this.
Dr. Larsen: Yeah, in terms of research, it really depends on exactly what the setting is. So some companies will have an open call for proposals, and sometimes that's going to involve students, and I've been involved in some of those, where you write a proposal and say, this is my research idea for a summer research project for a student or for a resident, and we submit it to the pet food company's scientific advisory board, and they decide whether they're going to fund it or not. And so the parameters of that are very well spelled out, and when that research data gets presented at a conference or published in a paper form, and that's always the goal is to publish it in a peer review journal, the support for the company from the company is always disclosed. There has never, in my experience, been an expectation that the company has access to the data, and in fact, they can't. The data belongs to the University of California.
Dr. Kent: Yeah, or the public if it's, you know, funded federally.
Dr. Larsen: Yes, of course. Yeah. And so we actually wouldn't give them access to the data and they wouldn't have veto power on whether things get published or not. They're just simply acknowledged as funders of the project. In other instances, we work with them more collaboratively where maybe we come to them or they come to us and we say, we want to do a clinical trial in patients that have a specific disease using the specific strategy or a specific diet. And we all work together to make that happen. And in those cases, that's very transparent. We decide what the outcome is going to be, who's paying for what, and all of that is upfront. And that's all publicly available information. So nothing is a secret.
Dr. Kent: and its disclosed in the paper.
Dr. Larsen: Yeah, absolutely. Absolutely.
Dr. Kent: So I kind of want to wrap up by asking you, what's the future for cat nutrition and cat research? Where do you think the questions are not yet answered and what do we need to do?
Dr. Larsen: There's so much we need to know. I really do think that some of the data that we can collect about cats at home is going to be critically important. And so...
Dr. Kent: You mean indoor cats?
Dr. Larsen: Yeah, cat owners as our partners in data collection.
Dr. Kent: Ahh..citizen science.
Dr. Larsen: Citizen science, yes. And that might involve technology. So there's definitely some disclosure and ethics. And if we have a camera, for example, on a food bowl that shouldn't be collecting audio in the household and those kinds of issues. There's some sensitive data collection issues that should be worked on.
Dr. Kent: Privacy issues.
Dr. Larsen: Exactly. But we have like little devices that we can put on cat collars that are essentially accelerometers, essentially like a cat Fitbit or an activity monitor that will sort of measure that kind of information. I mean, as you know when cats come into the veterinary clinic, they're not the same cat that you had at home, right?
Dr. Kent: They're not at all.
Dr. Larsen: They're a little fearful. Maybe they're loafing in their carrier or on the table.
Dr. Kent: Depends on the cat.
Dr. Larsen: Depends on the cat. But we would really like to know what they're doing at home. Are there different types of diets that might influence their activity? Maybe they act differently when they have more or less water in their diet or if they're on a weight loss plan. So those kinds of sort of partnerships with cat owners, I think, are going to be more and more important as we try to collect more information on cats.
Dr. Kent: This has been really great. Thank you again for taking the time to join me. I really appreciate it and I'm sure our listeners do as well. So thank you, Dr. Larsen.
Dr. Larsen: Thank you so much for having me. It's been fun.
Dr. Kent: This has been great. Thank you.
The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E03: Vaccines
- Read the Transcript
- Dr. Sykes: I think the future looks bright for vaccines as we have new vaccine technology. And as bad as the pandemic was, one of the best things that came out of it was just innovation in vaccine design.
Dr. Kent: Welcome to today's segment of The Vetrospective. This is your host, Dr. Michael Kent. I'm a professor at the UC Davis School of Veterinary Medicine, where clinically I practice as a radiation oncologist. Vaccines. What comes to your mind when you hear this word? The word vaccine comes from the Latin root vacca, meaning cow. So how did this happen? The name of the cowpox virus is Variola vaccinia, and back in 1796, a British physician, Edward Jenner, used this in a sense to infect or immunize people with the cow smallpox virus, which did not cause serious disease in people, but in turn protected them from smallpox, which was a serious life-threatening disease at the time.
Since then, multiple vaccines have been developed to prevent or even now treat disease. Of course, most people are familiar with vaccines available for humans, like measles, mumps, rubella, flu, and more recently, the COVID-19 vaccine. So what about vaccines for your dogs and cats? This is what we're going to have a talk about today, a deep dive with Dr. Jane Sykes.
Dr. Sykes is a professor here at UC Davis, and she has a special interest in small animal infectious diseases, particularly of dogs and cats and those related to public health. She has published over 150 peer-reviewed scientific publications and is the editor of several textbooks on canine and feline infectious diseases. She founded the International Society for Companion Animal Infectious Diseases and has held several leadership roles in the American College of Veterinary Internal Medicine, including serving as president and board chair. She has trained over 50 internal medicine residents in her career and several clinical infectious disease fellows. She is also director of our Center for Continuing Professional Education. She speaks internationally on infectious diseases and also postgraduate veterinary education. And then just as a fun side note, she is the person behind Ask a Vet, the column she does for the Washington Post. So it's my pleasure to have you here, Dr. Sykes. Thank you for taking the time to join me on the Vetrospective.
Dr. Sykes: Thanks for the opportunity to participate.
Dr. Kent: It's great to have you. So I always ask this person, this person. I always ask our guests this question because I find it really interesting. We always get different answers. And why did you become a vet?
Dr. Sykes: Yeah, I kind of have the classic story. I wanted to become a vet when I was seven. So it's kind of as far back as I can remember. I actually remember being in elementary school in the bathroom and telling somebody I wanted to be a vet. And that was kind of the turning point. And I just loved animals. But my dad was a doctor and my mother was a high school teacher. So I've been fortunate enough to combine those aspects of my life to become a veterinary educator.
Dr. Kent: That's perfect. And what made you interested in infectious diseases in particular? So, you know, that's a fairly specialized and important area, but a specialized area in veterinary medicine.
Dr. Sykes: Yeah, I was actually really became really fascinated in infectious diseases during vet school. Especially, I really enjoyed microbiology and I had a great microbiology teacher, professor, who encouraged me to pursue a PhD in veterinary microbiology. And that kind of was the beginning of my infectious disease career.
Dr. Kent: That's very cool. So I think maybe starting with some of the basics makes sense. So could you explain to me what a vaccine is and how they work?
Dr. Sykes: Yeah. And so you've kind of introduced this with the story that you began with, but a vaccine is a modified or a killed or a portion of a bug. And it's usually a virus or bacteria, and it's given to stimulate an immune response that's then going to protect you from natural infection.
Dr. Kent: So your body remembers this. Not real infection, and then can protect you later from exposure to it.
Dr. Sykes: Yep, exactly.
Dr. Kent: So what is the difference between, you mentioned killed and live, I know there's modified live vaccines, and then even the new mRNA vaccines that we've heard so much about over the last five years.
Dr. Sykes: Yeah, so we have a lot more different types of vaccines now than there were previously. One of the classic types of vaccines is a modified live vaccine. It's usually a virus. It's sort of a weak virus or what we call an attenuated virus and that replicates in the body. It doesn't make you feel really sick, but stimulates an immune response. In contrast, a killed vaccine is a completely inactivated bug that doesn't replicate. And so usually they have additional components of those vaccines that help to boost that immune response. So often contain things like adjuvants to help stimulate the immune response or create that really strong immune response needed. You mentioned mRNA vaccines. Yeah, so those are small pieces of nucleic acid, a little bit like DNA. They're actually copied from a DNA template from a bug. So this is less likely to actually cause all the same signs that an attenuated virus, an intact virus, might cause. And there was a lot of innovation in these vaccines as a result of the COVID pandemic. And now they're actually starting to appear on the market for companion animals as well. And they're actually great vaccines because they can be easily modified, such as when there are new strains of a virus that starts circulating. It's much easier to scale up production of slightly different mRNA vaccines that can stimulate an immune response.
Dr. Kent: So they use the genetic code or a piece of the genetic code from the virus, let's say, or I guess it could be bacteria as well, but I haven't heard of a mRNA vaccine against a bacteria. And it takes that bit and replicates it in the body. And is that how we get the immune response?
Dr. Sykes: And it produces antibodies to what that codes for. And that can help to protect you from natural infection.
Dr. Kent: And I'm sorry, go ahead.
Dr. Sykes: So I was also just kind of mention that there are other types of vaccines that are even in more widespread use in companion animals. And so we have these recombinant vaccines, for example, which are used for Lyme disease is one example where we have just a little piece of protein from an organism that stimulates this.
Dr. Kent: So when you say recombinant, are you meaning that we're taking a coding again and then somehow displaying that to the body? How would you explain that?
Dr. Sykes: Yeah, so again, these vaccines are actually produced by companies that make vaccines using a bacteria such as E. coli, for example, where they make large amounts of just a little bit of protein using that bacteria. And that's the recombinant process that allows you to.
Dr. Kent: So kind of how we make insulin a lot of ways now.
Dr. Sykes: Yeah.
Dr. Kent: Okay. So these are not necessarily new technologies, they're pretty proven and the like. We're going to talk more about safety later because I think that's a really important topic. But I kind of want to ask you first, what are the core vaccines? What are the ones, you know, we hear about core vaccines these days? What are the core vaccines for dogs and then for cats?
Dr. Sykes: So vaccines for dogs and cats are broken down into these two categories, core vaccines and non-core vaccines. The core vaccines are for every dog and cat, right? They're important.
Dr. Kent: The essentials.
Dr. Sykes: The essentials, right? They're either bugs that cause really severe disease, that can't easily be treated, for example, with antibiotics, or they're just really, really common and then they're an important cause of what we call morbidity, just kind of not feeling very good.
Dr. Kent: Yeah.
Dr. Sykes: And then we have the non-core vaccines, which are reserved for dogs and cats that might be at greater risk for certain diseases, just as you might get vaccines for yourself if you travel to certain countries.
Dr. Kent: Okay. And so I know, like, for example, rabies is considered a core vaccine. And while rabies is nearly always fatal, for people and for animals as well, there's a real public health concern there also, right?
Dr. Sykes: Yeah. So rabies is one really important reason for vaccinating dogs and cats in the United States. In countries where dog vaccination for rabies is not practiced, rabies is a really important public health problem as it results from transmission from dogs. In the United States, rabies is mostly a problem in wildlife like bats and raccoons and skunks and so it's important to vaccinate dogs and cats so that they're not likely to be infected from those wildlife species. And then, you know, when dogs and cats become infected, they can spill over to humans.
Dr. Kent: Usually a bite, right?
Dr. Sykes: That's right.
Dr. Kent: Yeah, and so actually the fact that they are vaccinated is what keeps these spillover events from happening.
Dr. Sykes: Yeah, there was actually a really amazing story about a softball tournament in North Carolina where some kids found a kitten that was sick and they were all playing with it at the softball tournament. There were people from multiple states that came in and played with this kitten. And then over the next few days, the kitten got sick and the mother of a kid took the kitten to a veterinary clinic.
Dr. Kent: Very responsible.
Dr. Sykes: Yes, and the veterinarian actually euthanized this cat because it had bad neurologic signs. And then the mother went back home to her house and she started thinking about rabies. And she actually called the veterinarian and she said, will you test that kitten for rabies? And her veterinarian hadn't thought about rabies, but because she called the vet, the kitten was tested for rabies and found to have it. And so as a result, hundreds of kids had to be treated with post-exposure prophylaxis.
Dr. Kent: Which is not pleasant.
Dr. Sykes: Yeah.
Dr. Kent: it's not pleasant. I know, you know, for humans, rabies vaccine isn't considered a core vaccine. I mean, all of us who in the veterinary field are all vaccinated for it, but the general population isn't. So it's a pretty scary disease if a human is exposed.
Dr. Sykes: Yeah, so you can see it still can be an important problem. It's another reason why even indoor pets need to get vaccinated for rabies because bats can be in houses. And so.
Dr. Kent: And bats can carry it.
Dr. Sykes: Bats can carry it.
Dr. Kent: In fact, I've heard more of the main ways people now can get exposed is if they're going to caves with bats and then they can actually inhale it from the of the bat feces, right? So some of the other ones that we talk about also, some of the other ones, let's say parvovirus for dogs, you know, why is that something that we need to vaccinate for?
Dr. Sykes: Yeah, so let's talk about dog-core vaccines.
Dr. Kent: Yeah.
Dr. Sykes: All vaccines for dogs are parvo, distemper, and adenovirus, which causes a disease called infectious canine hepatitis, in addition to rabies. One of the most common infectious diseases of that group is canine parvovirus infection, which is a severe viral disease, most commonly affects puppies, but sometimes we see it in young adult dogs that haven't been properly vaccinated. And it causes really bad vomiting and diarrhea and dehydration and bone marrow suppression and death if it's not treated.
Dr. Kent: Aggressively. Yeah, I remember. during my internship, I was in inner city Philadelphia and there were a lot of unvaccinated dogs coming in. And during vet school, I had never seen distemper and I had never seen parvo, but in all the unvaccinated dogs there, we regularly saw parvo and we regularly saw it on a cat, had leukopenia, diseases I had never seen before and kind of was a lesson to me on the importance of vaccination.
Dr. Sykes: One of the really important things about parvo that makes it special and makes it so successful as a cause of disease in dogs is because it can survive in the environment for very long periods of time. It can survive more than a year in the environment. So if a dog has diarrhea outside and that dog has parvo, then the virus can persist there for a very long period of time. It's one of the reasons why we say that dogs that are getting their puppy series of vaccines should be kept relatively away from the outdoors, not just other dogs, because they can become infected during that time that they're getting their puppy series.
Dr. Kent: Really important advice. So for the first three months or so, your dog is not really protected, right?
Dr. Sykes: That's right. And so these vaccines that we give to puppies and kittens, they're called a series. They're not boosters. They're given multiple times over a course of about 16 to 18 weeks, in order to wait for the time when puppies and kittens lose the antibody that they get from their mothers.
Dr. Kent: From the colostrum, right? Yes, when they're nursing.
Dr. Sykes: Yeah, and so those antibodies actually stop vaccines from working properly. And so we've got to wait for them to disappear, but we don't really know how long an individual puppy or kitten is going to take to lose those maternal antibodies.
Dr. Kent: So it's important to get the whole series.
Dr. Sykes: That's right. Yeah.
Dr. Kent: And that's not considered a booster, like you're saying, but that's just the initial vaccine.
Dr. Sykes: That's right. So we give the series. And if the last vaccine in the series is given before 16 to 18 weeks, then that puppy or kitten might not be protected from that infection. And it's why we often give this additional vaccine at either six months or a year for those animals that still had maternal antibody at 16 weeks.
Dr. Kent: So that's the first booster in a sense is just it is really your insurance policy.
Dr. Sykes: That's right, yeah.
Dr. Kent: So what about cats? What are core vaccines for cats?
Dr. Sykes: Yeah, so core vaccines for cats are feline herpes virus, feline calicivirus, and panleukopenia, which you also mentioned, as well as rabies. And then for cats that are a year or younger, core is also feline leukemia virus.
Dr. Kent: Now, for feline leukemia virus, since that's a virus that's transmitted close quarters or direct contact. Is that an essential vaccine for a cat who's indoor?
Dr. Sykes: Yeah, so feline leukemia virus, as you said, it's actually shed in a cat's saliva and so close contact among cats can transmit it. And actually bringing cats indoors promotes transmission of that virus because cats are living closely together. They're often sharing food and water dishes, for example. There's mutual grooming that goes on, and all of those things can serve to transmit the virus within indoor environments. And so for people who have a cat that's not infected with feline leukemia virus, and then they might bring a new kitten into their household, there's the potential for their existing...
Dr. Kent: Existing cat to become infected from an introduced cat from the new kitten they got, whether the shelter or breeder. You know, I know most cats are tested for this, but the tests may not detect the infection at certain points, right?
Dr. Sykes: That's right. The tests have limitations. They can be negative if it's very early. And then sometimes cats can go positive and negative and positive and negative. And so you can miss a positive cat sometimes with those tests. So they're not perfect. They're helpful. But it's good to have the insurance from a vaccine because of that.
Dr. Kent: So now some of the core, non-core vaccines we talked about or just briefly mentioned. What about Lyme disease? Is that a vaccine that's considered core or why not?
Dr. Sykes: Yeah, so Lyme disease, just like people, dogs can get Lyme disease. It's not a disease that we see in cats. So Lyme vaccines are just for dogs. It's a non-core vaccine. It's used for dogs that are at risk. And that's because Lyme disease has a very special geographic distribution in the United States, right? It's most common in the Northeastern states and also in the upper Midwest. And yes, we see some Lyme disease in Northern California here, but it tends to be limited to just certain regions of Northern California. And it's nowhere near as common as it is in those other parts of the country.
Dr. Kent: Where the ticks carry the disease, right?
Dr. Sykes: Exactly right.
Dr. Kent: And now there's not a Lyme disease vaccine for humans at this point, is that correct?
Dr. Sykes: That's correct. They did used to be a Lyme vaccine for people called LYMErix. And ultimately, because of controversies surrounding adverse effects of vaccination, the LYMErix vaccine was withdrawn. But there is a new Lyme vaccine that's currently going through clinical trials. It's looking really positive, and it's a recombinant vaccine, like I mentioned, which is very similar to the ones that are available for dogs.
Dr. Kent: Now, I know I haven't practiced general practice or been on the East Coast in a long time, but I know when I was, again, in my internship, we used to talk about how the Lyme vaccine at the time might actually cause worse disease in animals. So is this still the same vaccine that it was 25 years ago?
Dr. Sykes: I mean, yes, the vaccine's very similar, but I think that there really wasn't very good evidence to support that concern. And what's really neat about the Lyme vaccine is that it actually works in the tick rather than in a dog. So you vaccinate your dog, it develops antibodies to the Lyme organism, Borrelia burgdorferi. And then when the tick bites your dog, it ingests those antibodies and the antibodies work in the tick, and not in the dog.
Dr. Kent: So it bites the next dog and they can’t infect it.
Dr. Sykes: And then the organism is not transmitted. So it's actually a really cool vaccine because it's working in the tick.
Dr. Kent: It works in a different way. So you're almost vaccinating against the tick. So what about rattlesnake vaccine? I know that's been controversial too at points.
Dr. Sykes: Yeah. So there is a conditionally licensed rattlesnake vaccine. This vaccine has been a little bit controversial and the studies that have looked at it have shown, in some case maybe that it is beneficial and other studies not, but the studies haven't been very large studies. So I don't think we have great studies out there to be able to make a conclusion.
Dr. Kent: Yeah, that's right. And you know, rattlesnakes are around us here in Northern California, but they are not really that widely spread throughout the US. So it'd be a regional vaccine regardless.
Dr. Sykes: Definitely like a non-core vaccine. There's also been some concerns about allergic, bad allergic reactions to that vaccine. It's especially been seen in animals that got the vaccine and then got bitten by a rattlesnake.
Dr. Kent: And now I was going to ask you about Bordetella, which is something for dogs that is often required by kennels if you're going to board the dog. So what's the effectiveness of that vaccine and should it be given to dogs who aren't going to necessarily be boarding?
Dr. Sykes: So Bordetella is again a non-core vaccine. It's really reserved for dogs that are likely to be exposed to pathogens that cause canine infectious respiratory disease.
Dr. Kent: What we call kennel cough.
Dr. Sykes: Yeah. So it's definitely dogs that are going into doggy daycare environments or being boarded. Dogs that contact other dogs, like in dog parks, potentially could get infected. But most of these respiratory diseases are going to be best transmitted in indoor type environments where dogs are congregated.
Dr. Kent: Yeah. Is Bordetella the only agent that causes kennel cough?
Dr. Sykes: No, there's actually at least 17 different bugs that could cause.
Dr. Kent: So it's not necessarily going to be fully protective either, but it's the portion we can vaccinate for, right?
Dr. Sykes: Yeah, there's lots of different viruses and bacteria that can cause that disease.
Dr. Kent: And I know I'm making this a laundry list, but I think it's pretty interesting to go through these, so I hope you don't mind. What about canine influenza?
Dr. Sykes: Yeah, so canine influenza, there's two different types of canine influenza that we have vaccines for. One is the H3N8 type, and one is the H3N2 type.
Dr. Kent: So those are just designations for the type of influenza or flu. Just naming them, right?
Dr. Sykes: Yeah, just like we've been talking about H5N1 viruses circulating. We don't have an H5N1 vaccine, but these vaccines for influenza are subtype specific. So they are only going to protect against that subtype, which is why we've had these two different vaccines for dogs. The H3N8 virus, though, which emerged in the early 2000s and actually jumped from horses to dogs, was mostly a problem in shelters. And now it's believed that that's extinct in the United States. So we really probably don't need vaccines for H3N8 anymore. But the H3N2 virus keeps getting brought back into the United States from dogs in Asia, especially Korea and China. And we keep getting reintroductions of that virus, which then causes outbreaks, again, oftentimes in shelters, but sometimes it can spread to the community.
Dr. Kent: So is that, that's why it's not a core vaccine, because it's not a pandemic or epidemic in a sense, it's just sporadic infections in the US. Is it serious enough that you should consider getting your dog vaccinated if you're, let's say, in an area with, you know, a lot of dogs? et cetera.
Dr. Sykes: I mean, I think if your dog mingles with a lot of other dogs, again, indoor environments is going to be the most common way, then there's a reason to vaccinate. So usually dogs that are getting Bordetella should also get H3N2.
Dr. Kent: There's also some non-core vaccines for cats. And we actually are having Dr. Terza Brostoff on to talk about FIP and we'll be talking about FIP vaccines on a different episode, but maybe you could run through some of the non-core vaccine for cats and how effective they are and which cats might be best, vaccinated with them.
Dr. Sykes: So first of all, I'll talk about FeLV and FeLV for cats older than a year of age is a non-core vaccine. The thing about FeLV is when cats get older, when they get to adult age, their own immune system protects them well from that viral infection. So it's mostly going to be cats that are really at risk of exposure to the virus, especially cats that go outdoors and could encounter other cats that might be shedding FeLV, because that FeLV can be transmitted through biting as well. So non-core for cats older than a year of age, but because we really often don't know what people are going to do with kittens, it's core for cats under a year of age.
Dr. Kent: Yeah, and then let's just jump to FIV.
Dr. Sykes: Yeah, so there is no vaccine available for FIV anymore in this country?
Dr. Kent: Just like the HIV there isn’t.
Dr. Sykes: Yeah, and there used to be one here, actually, it was discontinued about seven or eight years ago now. And one of the problems with that vaccine, in addition to it not working very well for all strains of FIV, it also interfered with diagnostic testing for infection. And we still have some cats that were vaccinated seven years ago that have antibodies from vaccination that test positive for the disease and we still are struggling with that even now. So there's no FIV vaccination in the US. There is in other countries like Australia.
Dr. Kent: Yeah, and are there other vaccines I'm missing for cats? I think there's like for—there are a few others, maybe you could touch on those.
Dr. Sykes: Yeah, so we also have a Bordetella vaccine for cats. And we also have a chlamydia vaccine for cats. And chlamydia causes conjunctivitis, runny eyes, and sometimes sneezing in cats. It's a respiratory pathogen. And those Bordetella and chlamydia vaccines, mostly probably in young cats and catteries, so typically reserved for those cats. And then we've had a somewhat controversial FIP vaccine, which I think you're probably going to talk about with Dr. Brostoff.
Dr. Kent: Yes.
Dr. Sykes: Our current FIP vaccines are not very effective.
Dr. Kent: Not effective. Problematic, yeah.
Dr. Sykes: One of the other vaccines that's really important and that has recently had a change in recommendations is the lepto vaccine for dogs.
Dr. Kent: Actually, I meant to ask you about that because that's something that I know changed over the years.
Dr. Sykes: Yeah.
Dr. Kent: And so lepto or leptospirosis, that's a bacteria that can cause kidney infections, right?
Dr. Sykes: That's right. It's a bacterial infection. It's transmitted in urine and often wildlife or domestic animal reservoir hosts like cattle and sheep and horses can shed this bacteria in their urine. And then that can contaminate water sources and dogs can get infected through exposure to those water sources or through eating rodents. And actually rodents are the most important reservoir hosts for lepto, like, there's a one in three chance that a brown rat that you see is shedding lepto. Yeah, really common.
Dr. Kent: Which is also a public health concern, right? I mean, because people are susceptible to this bacteria also.
Dr. Sykes: People can get lepto and it's become a big issue in big cities where there's been rodent overpopulations recently.
Dr. Kent: Because most of the time viruses don't jump between species easily, but bacteria is bacteria and infects everyone. So like rabies is kind of the exception, right? Where rabies infects all mammals and it's one virus. But leptospirosis really affects any mammal.
Dr. Sykes: Any mammal, even people. And actually any mammal can just look perfectly healthy and be shedding lepto in its urine, including people.
Dr. Kent: And sometimes you're clinical for it and sometimes you're not. Let's say you are infected and you're susceptible to this infection. What's the consequence of it being affected?
Dr. Sykes: Yeah, so when it causes disease, like you mentioned, it causes severe kidney disease and also liver problems, but any organ in the body can be affected. It can cause lung problems, gastrointestinal problems, even involve the brain. So it's a multi-systemic disease. It can be fatal if not treated aggressively.
Dr. Kent: So now there's different forms of leptospirosis or serovars, I think they're called, right? So how good is the vaccine at protecting dogs, cats from this disease?
Dr. Sykes: So these different serovars all have different outer coatings and the vaccines only protect against the serovar that they contain. So our lepto vaccines for dogs have four different serovars in them. So to protect against at least those four different serovars.
Dr. Kent: And are those the most common serovars out in the environment?
Dr. Sykes: We actually don't know, but we do know that the vaccines stop dogs from getting disease because dogs that are vaccinated for lepto don't get sick. And so we've actually been studying a really interesting outbreak of lepto in Southern California that involved over 200 dogs in the West Los Angeles area. And so people got to know about this outbreak, which was connected to a couple of doggy daycares in the area. And they were actually going to their vets and saying that they'd heard about this outbreak and they wanted their dogs to be vaccinated for lepto. But because lepto wasn't a core vaccine and the practitioners in that region were not vaccinating for lepto, they didn't even have the vaccines in stock.
Dr. Kent: Wow.
Dr. Sykes: And so they started vaccinating because of owner demand, because they learned about this outbreak and were worried about their pets. And now lepto is recommended as a core vaccine. So since that outbreak occurred, the recommendations have changed from non-core to core. So every dog, every year, lepto.
Dr. Kent: And how effective is it? Like you said, it will stop disease.
Dr. Sykes: Yeah, and like I said, we have basically not diagnosed lepto in dogs that have been fully vaccinated for lepto. All the dogs we diagnose here at UC Davis have not received lepto vaccines.
Dr. Kent: You brought up another point, which I'm just going to shift our conversation a little bit. You said every dog lepto vaccine every year. So now the question of how often do we vaccinate? Should all these vaccines be given yearly? How do you determine how often a booster is needed? You know, because there's concerns about over vaccinating or vaccinating too often.
Dr. Sykes: Yes. So this is a really good question. And for these bacterial vaccines, the ones that are, that use killed vaccines or recombinant vaccines, where you.
Dr. Kent: So Bordetella is bacterial or viral.
Dr. Sykes: So Bordetella is a bacterial.
Dr. Kent: Bacterial. So that's a yearly one.
Dr. Sykes: Yes, although it's also a respiratory vaccine, and so the respiratory pathogens usually need yearly vaccination.
Dr. Kent: And then lepto is a killed bacterial, so we need that yearly.
Dr. Sykes: Yes.
Dr. Kent: And what else?
Dr. Sykes: So Lyme would be another example that's a recombinant or killed vaccine that has to be given yearly as well.
Dr. Kent: Okay.
Dr. Sykes: But now we have a core vaccine that's an annual vaccine, whereas in the past, our modified live viral vaccines, our distempo Pavo vaccines, herpes, calici and cats, we were giving every three years.
Dr. Kent: Yeah, and even rabies is every three years. After the first booster. Yeah.
Dr. Sykes: So that's a major shift, right? Because for dogs that were just getting core vaccines in the past, they were coming in every three years for vaccination. But now because lepto is core, all of those dogs are coming in yearly to get the lepto vaccine.
Dr. Kent: That's a big shift. That's a big shift. And so do we still need to do every three years, let's say for the parvo and distemper and parainfluenza, those cores, does the protection only last three years?
Dr. Sykes: Yeah, so for parvo and distemper and adenovirus, the three organisms that are core in dog vaccines, really those vaccines are going to probably provide lifelong vaccination once the puppy series has been completed, so long as you got that last vaccine at the right time, probably it's going to be lifelong immunity. The recommendation still is every three years, the vaccines are really safe and unlikely to cause side effects. So it's felt that three years is appropriate at this time. But I think in this era of vaccine hesitancy, we are starting to think about some of those vaccines like parvo and panleukopenia and whether those ones which have really strong long duration of immunity, do they really need to be given every three years? Still the recommendations from AAHA and WSAVA is that they'd be given every three years.
Dr. Kent: And those are some of the main veterinary groups that look at this. Yeah. So is there other ways that you can tell if you're still protected? You can run some blood tests for that.
Dr. Sykes: Yeah, so there are tests that are available to look for antibodies, but if you don't have antibodies, it doesn't mean that you're not protected. And so I think also these vaccines have become so safe in recent years with improvements in vaccine technology that there's such a low risk of having any sort of side effects from them ,that it's better to vaccinate.
Dr. Kent: So now I really wanted, I want to take this conversation in two directions based on what you said. Now I can't decide which to do first, so I'll let you choose. I want to talk about vaccine hesitancy, but I also want to talk about the safety of vaccines. So maybe let's talk about safety of vaccines first. I'm going to take that from you, sorry. And then we'll talk about vaccine hesitancy, because that's something that's come up more and more. So what are the risks of an allergic reaction to a vaccine?
Dr. Sykes: Yeah, the risk of any sort of allergic reaction is extremely low, like less than 0.5%. Maybe even less than 0.1% for some vaccines. But the risk is not even. Like there are some animals that are more likely to have reactions than others. And remember that a vaccine is designed to produce an immune response.
Dr. Kent: Yes.
Dr. Sykes: It's designed to cause inflammation. And so it's normal to have a little bit of a fever, you know, and pain at an injection site, just like we all do when we get vaccinated. A vaccine is supposed to produce an immune response. So we've kind of got this balance between wanting to create inflammation and immunity and wanting to minimize the side effects of those. Most reactions in dogs and cats are going to be soreness at the vaccination site or sometimes just a little nodule, local reaction, bump, at the vaccination site. Really rare are these sort of anaphylactic type reactions that people worry about where animals can get, you know, swollen faces or they can collapse and need emergency treatment.
Dr. Kent: And that was more common. decades ago, right? With some of the formulation of the vaccine. So that's, do you think some of that's holdover from old knowledge?
Dr. Sykes: Yeah, I mean, we still, we still see them. I still talk to practitioners on a regular basis who have seen allergic anaphylactic type reactions. So they're not, you know, completely gone, but they're certainly less frequent now than they were decades ago.
Dr. Kent: And they're treatable, right?
Dr. Sykes: Yeah.
Dr. Kent: So What about autoimmune disease? Because I've heard people talking about that too. the concern that over vaccinating or repeated boosters can cause autoimmune disease in dogs.
Dr. Sykes: Yeah, there's actually been quite a lot of studies looking at this and no link between vaccination and autoimmune disease. We have not found a connection, proven connection, between vaccines in dogs and cats and autoimmune disease. However, for dogs and cats that have been diagnosed with autoimmune disease, which is more common in dogs and in cats, so cats rarely get autoimmune diseases. I say cats don't like to self-destruct, worse dogs self-destruct a lot more often. So for those dogs that have, you know, had autoimmune hemolytic anemia or autoimmune joint disease, If those animals have been controlled with the drug therapy that they're in remission and their signs are being controlled, I think it is possible for a vaccine to then sort of disrupt that balance and they can.
Dr. Kent: Re-stimulate the immune system, which may include stimulating the immune system against your own body.
Dr. Sykes: Yeah.
Dr. Kent: So that's something that you would talk to your vet about, the benefits and risks and maybe consider holding off on the vaccines where possible. So for cats though, there is a real risk. We see injection site sarcomas, being an oncologist, I still see those, though much less frequently than we used to. So the risk is very low. I've seen numbers saying anywhere 1 in 10,000, 1 in 50,000. No one really knows how commonly they occur, but they do. Even with the new reformulated vaccines, We still see them on occasion. So how do you balance the risk for infectious disease versus that's a true potential side effect of a vaccine?
Dr. Sykes: Yeah, you know, I think that the risk of injection site sarcomas is really a lot lower than it used to be.
Dr. Kent: I agree with that, but it's still there, but it's lower.
Dr. Sykes: I don't know. I think that, yes, it's a risk, although extremely low. And I think that these infectious diseases like panleukopenia are really severe. Feline leukemia is a horrible disease. We see it all the time.
Dr. Kent: I mean, both of those could be fatal. And panleuk is almost always fatal, right?
Dr. Sykes: Yep. And calici and herpes are a really big problem in the cat population. They cause bad respiratory diseases. So I think the risks of injection site sarcomas are outweighed by the severity and frequency of these infectious diseases.
Dr. Kent: So now I'm, this may be a little bit of a loaded question. I'm not trying to bait you or maybe I am, but what about the risk of autism in pets after vaccination? I've heard this is a concern that's been raised.
Dr. Sykes: Yeah. So can I actually just back up a little bit on the injection sites?
Dr. Kent: Oh yeah, please, And then you can answer that question.
Dr. Sykes: So one other thing that I have to say about injection sarcomas is that owner awareness of this issue is very important.
Dr. Kent: Yeah.
Dr. Sykes: And so the reason for that is that then owners can be monitoring injection sites, not just vaccines, but other injections for any little lump that appears at the site and early diagnosis of injection is going to lead to much better outcomes than if they're left.
Dr. Kent: Definitely, important. So if you see a persistent lump at the site of an injection, you need to go in and have it checked is what we tell people. And we want to make sure because it could be a fairly small surgery if you catch it very early as opposed to needing surgery, radiation, and chemotherapy if it goes later and we may not be able to control it. So definitely thank you for bringing that up.
So what about the autism question?
Dr. Sykes: Autism, and I wasn't trying to skip that one.
Dr. Kent: Maybe you should.
Dr. Sykes: But yes, I mean, there has actually been some studies that suggest that some people might believe that vaccines in pets can cause autism, but dogs and cats don't get autism. So there's been no connection between vaccination and actually any sort of cognitive problem in dogs or cats. One of the problems with vaccination is because pets are vaccinated quite frequently, like every year, and especially in young dogs where they're getting vaccinated.
Dr. Kent: Multiple vaccines, yeah.
Dr. Sykes: It's difficult to separate vaccination from disease that might just be occurring anyway, right? So your pet could get a vaccine because it's being vaccinated every single year. And then a few months later, it could develop diabetes or some other condition. And you might be tempted to say that the vaccine caused that when it just was just a coincidence. So it's sometimes difficult to disconnect the vaccination for a problem that occurs after vaccination. And yes, there's been concerns about autism and diabetes and other things, but there's absolutely no proven link to any of those problems.
Dr. Kent: So I wanted to just quickly ask also is, should a pet get multiple vaccines at the same visit or does that make them less safe or is there more risk with that?
Dr. Sykes: Yeah, and actually it's very common for vets in practice to try to spread out vaccine components to try to reduce the risk of having a reaction. So spread it out in time, in other words, rather than on a pet's body.
Dr. Kent: Yes.
Dr. Sykes: But really we recommend that now with the vaccines are so much safer than they used to be, it's better to use the opportunity to vaccinate your pet and give multiple vaccines at the same time. Using combination vaccines is recommended, just like they are used in human medicine. The problem with spacing them out is if you give vaccines too close together, the immune response to one vaccine can interfere with the immune response to the next vaccine. So when vaccines are spaced out, like for example, I'll give one vaccine this week and another vaccine next week, then you might not get an immune response to the second vaccine.
Dr. Kent: Because your body's already busy in a sense, fighting off this non-existent infection from the first vaccine.
Dr. Sykes: Exactly.
Dr. Kent: So I saw this, I tried to do a little research before talking with you, so I don't sound entirely stupid, but I saw this 2023 study that was published in the journal Vaccine that says about 45% of dog owners now think vaccines are unsafe. 20% think they're not effective and 30% don't think they're necessary, which I was kind of shocked when I read this. And I'm sure you've heard this, but what are your thoughts? What do you think is behind this? Why have we lost confidence in a large portion of the pet owning population?
Dr. Sykes: Yeah, so I think first of all, just got to be a little bit careful with some of the studies. They have different populations that are being surveyed and so there may be some biases and, response biases in that are choosing to do the survey because I am concerned about vaccination. Therefore, it's not representative of everybody.
Dr. Kent: Of all of America.
Dr. Sykes: Yeah, that's right. And we also know from other studies that people really, they have a lot of confidence in veterinarians' advice. And when veterinarians make recommendations surrounding vaccination, you know, people do tend to believe them and they're, They are very, veterinarians can be very helpful in choosing vaccine protocols. So I think that's the caution. But yes, there has been concern about vaccine hesitancy, especially along with the vaccine hesitancy for human vaccination and some evidence of spillover into pet owners.
Dr. Kent: Into veterinary medicine, it is happening as well. And What's the danger to our pets for that, to our dogs, to cats? is this a real problem? I know we hear about, measles outbreaks in humans now. And does this bode poorly for us in the veterinary world?
Dr. Sykes: Yeah, I mean, it's not good. And I think that, I think first of all, rabies is a public health issue. makes vaccination of pets essential. And of course, it's required by law. And for cats in many states, it's required by law as well. So we have the legal need for vaccination. And many people don't know that rabies vaccines are required by law for cats in many states.
Dr. Kent: Yeah, and actually the penalty for not vaccinated, depending on your particular county, if your dog or cat bites someone and they're not vaccinated, it could be quite severe, can either lead to long quarantines or even in euthanasia, forced euthanasia. So that's obviously very important from public health perspective as well.
Dr. Sykes: And then for the organisms like parvo that don't cause human disease, I actually know people who had vaccine hesitancy and didn't vaccinate their puppies for parvo and their dogs got parvo and died. So.
Dr. Kent: Gosh, that's terrible.
Dr. Sykes: You know, it's a bad disease and it's really common.
Dr. Kent: Well, and it's expensive. Like even if you have pet insurance, it can be thousands, many, thousands to get a dog through parvo. And not easy. So I don't want to end on kind of a sour note, but if you could make a vaccine today for an infectious disease that we don't currently have, an effective vaccine, what disease would it be for? And why?
Dr. Sykes: Yeah, so for cats, I would say FIP. Gosh, yes. You know, even though we have antivirals now that are very effective, vaccines that work for FIP are really needed.
Dr. Kent: And our team is working on one, and we'll be talking more about that with Dr. Brostoff.
Dr. Sykes: Awesome. And then for dogs, a couple of organisms. One's Ehrlichia canis, which is a tick transmutative bug that is actually one of the most common infectious diseases of dogs worldwide next to parvo. And, a challenging organism to develop vaccines for, but that would definitely be something that, for dogs can be very hard to treat in some cases. I would say also globally, leishmania, which is a protozoal disease, that's also a public health problem. And then for fungal diseases, the one that I study, which is Valley Fever. There's vaccines in development right now for that, which would be the first fungal disease vaccine ever available.
Dr. Kent: Yeah, I hadn't heard of that. That's pretty cool. So what is the future of vaccines? What do you... see where we're headed? What do you think our future holds for us?
Dr. Sykes: Yeah, you know, I think we'll see, we'll continue to see better and safer vaccines and new vaccines for like some of those organisms I was talking about. I think the future looks, looks bright for vaccines as we have new vaccine technology. And as bad as the pandemic was, one of the best things that came out of it was just innovation in vaccine design. So I'm hopeful that we'll also have lepto vaccines that protect against all strains.
Dr. Kent: All serovars, all strains, yes.
Dr. Sykes: I think that will happen too. So we've got lots of optimism.
Dr. Kent: I like that. Being an oncologist, I like to say that I'm an optimist by nature. And so Dr. Sykes, thank you for taking the time out to speak with me and for our listeners. From the Vetrospective, it's an honor having you on.
Dr. Sykes: Thanks for the opportunity to talk to you about vaccines.
Dr. Kent: The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe-Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
S01 E02: Dog Food
- Read the Transcript
- Dr. Kent: Should I just buy the really expensive one because it's going to be the best?
Dr. Larsen: No, food costs do not correlate with quality necessarily.
Dr. Kent: Hello, and welcome to today's episode of Vetrospective. This is Dr. Michael Kent, a professor from the UC Davis School of Veterinary Medicine, and your host. Dog food. Dog food and nutrition. What at first seemed so simple can actually be a pretty complex topic. In my mind, what it boils down to, though, is what should I feed my dog? Yes, and I do have a dog. So this is so fundamental to your dog's life. Dog food and treats is also a huge industry. A quick Google search I did the other day showed me that the US market alone is valued at $65 billion a year. That's a huge number.
This combined with a lot of misinformation floating around out there, a lot coming from really well-meaning people and places, means how do we sort this all out? Should I feed kibble or wet, commercial or home-cooked? What about diet trends? Should I feed grain-free diets or raw or low-carbohydrate foods? It can get overwhelming.
So to try to help us sort all this out, I have asked, Dr. Jennifer Larsen to join us here today.
Dr. Larsen earned her PhD in nutritional biology and her DVM from UC Davis. She is a board-certified veterinary specialist in nutrition, and she's also service chief of the nutrition service here at the hospital. She provides clinical nutritional consulting and is director of an amino acid laboratory, mentors residents and students, and teaches in our veterinary curriculum as well as for a graduate group.
Before we dive into these questions, I'm going to ask you something I ask a lot of our guests. Why did you become a veterinarian and why nutrition?
Dr. Larsen: Those are great questions. Thank you, Dr. Kent. I'm so happy to be here.
Dr. Kent: Thank you.
Dr. Larsen: I became a veterinarian essentially to do exactly what I'm doing now. I was not one of those people that wanted to be a veterinarian for a long period of time because I was pretty ignorant about what that meant. So I thought veterinarians essentially gave vaccines and did spays and neuters. And that was pretty much the extent of my knowledge of what that involved.
Dr. Kent: Fair.
Dr. Larsen: And so once I came to UC Davis as an undergraduate and then went on to do graduate work and master's and started my PhD. I was working as a work study student, which is one of the financial support mechanisms we have on main campus. And that gave me the opportunity to work in some research labs alongside veterinarians that were training to be specialists and that were doing research to support their advanced training. And that really sparked my interest in the field and opened my eyes to what was possible. And I thought, this is more like what I want to do. So I actually didn't even apply to veterinary school until I was partly through my PhD program and then ended up doing those concurrently and ultimately went to college for 18 years.
Dr. Kent: 18 years. I don't even want to count how long I went to college. And I joke that I've never left. You stay at the university. I go to school. I don't go to work, you know. But so really, you kind of came to clinical medicine starting at research. So that gives you an interesting perspective.
Dr. Larsen: Yeah, I like being curious about things. I like learning things. And I feel that the more that I know and the further along I get in my career, not only am I hyper specialized, like a lot of us here at the university, but we have the ability to just text somebody or walk down the hallway and ask a question about something and being around emerging knowledge and people that know a lot about something else is great. It's the environment that I think a lot of us thrive in.
Dr. Kent: Yeah. So this is pretty interesting, but I, and We could maybe do a podcast on that. But I'm going to go back to feeding your dog. this is something that, like I said, is so fundamental. So the simplest way that I think about it is I go buy a bag of dog food either at the grocery store or box store or off the internet. But how do I tell if it's good? Like there's thousands of different brands. Like we said, this is a multi-billion dollar industry. So where do I even start?
Dr. Larsen: Yeah, that's a big question. And we get that question all the time. There's so many different marketing categories. And then within those marketing categories, different forms of food.
Dr. Kent: So marketing, marketing. So just explain that to me also, marketing versus nutrition. We're talking about nutrition, not marketing.
Dr. Larsen: Yeah, I mean, dog food, dog treats, pet supplies, it's a huge marketing category. And there's a lot of purchasing power in the consumers that own dogs and cats and a lot of people increasingly want to treat them like family. And so marketing is a strategy that's used to essentially sell you an idea or a product, separate you from your money in one way or another. And it's an entire discipline unto itself. But it's pretty well established that the same sorts of marketing strategies and techniques that are used to sell parents things for their children are used to sell pet supplies, pet food, pet treats to pet owners.
Dr. Kent: So how do I make sure I'm not giving them the high sugar? breakfast cereal, and I'm giving them good nutrition, because that's important, obviously.
Dr. Larsen: Yeah, nutrition is fundamental to maintaining health, prevention and treatment of disease, and that's what we do every day. And I love talking about food, but it is really more than food.
Dr. Kent: I love eating it.
Dr. Larsen: Yeah, it's the experience of eating it is very important too for us and for our pets. But the nutrients themselves also have an important role here, and how we deliver those nutrients can differ from food to food and from individual to individual. And so I think that a lot of people try to take some of the ideas from human nutrition and apply it to animal nutrition. And some of those are transferable, and that's reasonable. And in other cases, it doesn't really work, like the schemes that we use in human nutrition don't really work for pet nutrition. A lot of times when we're feeding our pets, we're feeding complete and balanced diets, which we really only employ for ourselves when it really matters, right? Like that's what baby formula is, milk replacers. When we send people to space or in the ICU or there soldiers out in harsh environments, that's when we use complete and balanced diets. But otherwise, if you're just a normal, healthy human or even managing a chronic disease, we sort of rely on people to make those choices for themselves every day.
Dr. Kent: Yeah, because sometimes I don't have veggies in the fridge and I might make a less balanced meal, but then the next one I'll make up for it. Is that that's what you kind of mean?
Dr. Larsen: Yeah, and I think people feel like they're pretty good at balancing out their diets and eating a wide variety, but from a population perspective, we're actually not that good at that. And that's why so much of our food is enriched or fortified. So rice is fortified, lots of cereals, certain dairy products that are lower in fat have to have vitamins A&D, et cetera.
Dr. Kent: Or why we put iodine in our salt.
Dr. Larsen: Right, So those are sort of population-based approaches to solve common gaps in what we're getting nutritionally.
Dr. Kent: So I'm still wondering, Dr. Larsen, where we fit this in. Why can't I just go and get some salmon, get some rice, maybe throw in a tablespoon of corn oil, because I know we need some fatty acids, and cut up some broccoli. And that should be enough for the dog, right? And if I feed that, isn't that going to be sufficient to really maintain their life and give them good quality of food?
Dr. Larsen: Well, we have to consider that dogs require about 40 essential nutrients.
Dr. Kent: 40.
Dr. Larsen: And they all have to be present in very precise amounts and ratios to each other and in a form that their body can actually use. And so in my opinion, the best use and the biggest advantage of a home cooked diet is our ability to customize it. And so as I'm sure all of your listeners are aware, dogs are the most diverse species in terms of size. We have everything from Chihuahuas to Great Danes and extremes on both of those ends. That is a huge difference in body size. And so making sure that they're eating enough calories from each of the different components in their diet, that we are supplementing their diet appropriately so that we're making sure that all of the essential vitamins and minerals and amino acids and so forth are all added are really important.
Dr. Kent: Those are those 40 nutritional items you're talking about.
Dr. Larsen: Yeah, there's fatty acids, there's amino acids, vitamins, minerals, there's some vitamin-like substances, as we refer to them. It's really important that they're all present in appropriate amounts.
Dr. Kent: Now, I'm going to fess up here. I don't feed my dog anything home cooked, but if we wanted to put that in, we could think about that. 10% is a topper thing, right? That might be a nice way to supplement it.
Dr. Larsen: Yeah, I think a lot of people like to do that. And that's a fine way to offer variety. A lot of dogs like fruits and vegetables, and they especially like things like meat and peanut butter.
Dr. Kent: Oh, anything that hits the floor, my dog eats. And you know, that's what s
Dr. Larsen: Retrievers aren't known for their pickiness necessarily.
Dr. Kent: So that's another thing. I feed my dog a Labrador retriever food. Why is there a Labrador retriever food? Now he likes it and I'm like, great. But he also likes anything. So I've obviously following for marketing or is there something that's different than the golden retriever food from the, and I know there is because once there wasn't Labrador retriever food and I bought golden retriever food.
Dr. Larsen: Yeah, there's lots of different breed specific diets for different breeds of dogs and cats. Some of that is marketing and some of it is based in science and actual like firm foundations for doing that. So for example, the diets that are designed for the animals that have sort of more of a round skull, those brachycephalic dogs and cats, so bulldogs and Persians.
Dr. Kent: The smushed face dogs we love so much.
Dr. Larsen: Short muzzled dogs and cats.
Dr. Kent: I used to have a pug.
Dr. Larsen: Those kibbles are designed to be a specific shape and texture that makes it easier for them to pick up so that they can get the food into their mouth and chew it more appropriately. The diet that you feed your dog is meant to not have a lot of calories for its weight to be a little bit more diluted out to prevent the weight gain. As you know, retrievers tend to never believe that they're full and they love to overeat and overweight is a big problem for them.
Dr. Kent: I've timed my dog eating 47 seconds. That's his average. So he eats his food in 47 seconds.
Dr. Larsen: And sometimes shorter.
Dr. Kent: Sometimes shorter if we let him. But yeah, no, I get it. I get it. So I've done it again and gone down a rabbit hole with you, but I want to bring us back to the grocery store. I picked up a bag. I'm looking at the label. I'm going to ignore the marketing because you warned me about that already, right?
Dr. Larsen: That's hard to do.
Dr. Kent: Yeah, I know. I'm a sucker for it.
Dr. Larsen: Everybody is.
Dr. Kent: Okay, I'm looking at the label. What's on the label and what should I be looking for?
Dr. Larsen: So the most important part of the label can actually be a very difficult thing to find, and it's referred to as the nutritional adequacy statement.
Dr. Kent: So is this kind of what's on my food when I go and buy something there? Is there anything like that on the human food? Are we looking for something different?
Dr. Larsen: Yeah, we're looking for something different. So human food is not meant to be the sole source of nutrition for people. But complete and balanced pet foods are intended to be the sole source of nutrition, or they can be fed that way. Treats are an exception, and there are some unbalanced foods that aren't intended to be fed every single day as the sole source of nutrition. So the nutritional adequacy statement is required to be on pet foods that are not specifically labeled as a snack or a treat. And it tells you three really important pieces of information. It tells you whether the product has a complete and balanced claim, and that is a legal definition. It's a claim. Secondly, it tells you how that claim was substantiated. And I'll get back to that in a second.
Dr. Kent: Perfect, because I need to know that.
Dr. Larsen: The third thing that it tells you is the species and the life stage for which the diet is intended. And so the life stage categories for dog and cat food are during growth, so for puppies or kittens. Adults, and then reproduction. There's also an overarching category called all life stages that can be fed to animals in all life stages. So whether you're growing, adult, et cetera. But there isn't a separate category for things like seniors, disease management, et cetera. So any claims for those uses are going to essentially fall under marketing and they might differ depending on the company's philosophy.
Dr. Kent: Okay, so you were going to come back to something.
Dr. Larsen: The substantiation.
Dr. Kent: Big word. So, how do we substantiate this?
Dr. Larsen: Yeah, so what that essentially just means is that the company is making a statement that their food is complete and balanced for growth of kittens or maintenance of adult dogs or something like that. So it's a species and life stage specific claim. That claim has to be based on the food being formulated to meet a specific nutrient profile, which is a regulatory guideline.
Dr. Kent: Okay.
Dr. Larsen: Or the food can go through a feeding test being fed to animals that are in that specific life stage. And then there's certain testing done to make sure that the diet is supporting them adequately.
Dr. Kent: So which is better? Like if it says that it's formulated, is that good enough or should it have gone through the trial you talked about?
Dr. Larsen: Like so much in nutrition, the answer is going to be it depends. So there are pros and cons to both of those methods. But ideally, a company would be formulating a diet to meet some nutritional standard to have a target profile and then they would be doing some sort of testing in an animal to make sure that the nutrients are bioavailable, et cetera. Because just because it looks good on paper doesn't mean that it's going to perform well.
Dr. Kent: Bioavailable. Now, what do you mean in terms of nutrition? I know what meaning bioavailable means your body can actually absorb it and use it, but why is that an issue?
Dr. Larsen: Yeah, that's an issue because if you analyze a specific food for specific nutrient profile in a laboratory, you're essentially figuring out how much of that nutrient is present in that food.
Dr. Kent: Okay, how much calcium is located in a cup of dog food?
Dr. Larsen: Right, right exactly. So you could do a chemical analysis, you could figure out that value, how many grams of calcium are in this cup of dog food. But how much your dog is actually absorbing and using is a different number because it's not going to be 100%. And calcium actually isn't that available depending on the form. Maybe you're absorbing 30% of it. And so those numbers are pretty well defined, but understanding how that specific food performs in a specific animal is really, really important.
Dr. Kent: And do you think we know what the nutritional requirements of dogs are? Is that pretty well established now over time?
Dr. Larsen: It's pretty well established for the typical foods that we are using in dogs. Now, there is some caution to that statement because we are often using data from specific situations and applying it to other situations.
Dr. Kent: That's what we do with everything in life.
Dr. Larsen: Yes, of course. Yep. And so we're learning more and more about other compounds that might be considered essential under certain circumstances, or maybe there's an interaction between nutrients or maybe under a disease state. So there's always more to learn, but we have the basics down pretty well.
Dr. Kent: So I'm going to bring you back to the grocery store again. I'm standing with this bag here and I'm finding the nutritional adequacy statement. And what is, what am I looking for exactly? What's going to be written there to tell me I should, it's okay to buy this bag of dog food?
Dr. Larsen: Yeah, so you want to think about the pet that you have at home. So do you have a growing puppy?
Do you have an adult dog that doesn't have any health problems? Or maybe your vet has sent you to the store to look for a specific kind or type of food. And so you're keeping those things in mind. If you have a healthy adult dog, as you mentioned already, there are thousands of different appropriate options. So you're essentially looking for a dog food that has a complete and balanced claim to cover the needs of adult dogs.
Dr. Kent: Okay. And is there a specific wording I should be looking for?
Dr. Larsen: It'll say something like, this diet is formulated to meet the dog nutrient profiles or animal feeding tests substantiate that this product supports this life stage.
Dr. Kent: Okay. And I'm now thinking like, I see this bag and it costs $70. This bag costs $90. This bag costs $110. Should I just buy the 110? Because you actually, full disclosure, Dr. Larsen knows me quite well. Jen is my good friend. She knows my dog. So should I just buy the really expensive one because it's going to be the best?
Dr. Larsen: No, food costs do not correlate with quality necessarily. There's so much that goes into how much a food costs. Some of it is the volume that the company is selling, what kind of outlets they're selling it through. Is it only online? Is it only through specialty stores? Are they selling it through grocery stores, et cetera? And then the size of the bag, so a bigger bag is going to cost less per pound than a smaller bag. There's also factors like is it a diet that needs to be refrigerated or frozen? Is it a canned diet? Those are way more expensive. So in general, if we want to think about the kinds of diets that are available out there, a kibble diet is by far the most popular, it's the most commonly used, and it's the most cost effective. Partly that's because it's dry, so you're not paying for water and for shipping.
Dr. Kent: And you're not shipping water or preserving water.
Dr. Larsen: And the packaging is much less expensive as well.
Dr. Kent: Yeah. That makes sense. So should I be feeding any of these refrigerated foods then if they're better? Are they necessarily any better or they look fresher? I see them, I see people bring them in.
Dr. Larsen: Yeah, people really like the idea of having a quote unquote fresh diet. And there's lots of these homemade style commercial diets out there, and they're very aggressively marketed. I think all of us that are on social media have gotten ads for those. We don't have any proof that they're better, and they're certainly going to be way more expensive. There are also concerns about nutritional sustainability in terms of the types of ingredients that we put in those foods. A lot of them are claiming to be human grade, which has a definition that essentially just describes a process. It doesn't differentiate nutritional value or quality.
Dr. Kent: So human grade, meaning it's what I go and buy at the grocery store.
Dr. Larsen: Yeah, it's essentially a food that is competing with the human food chain for those same things. And that sounds good. Like people like that. That word definitely has a health halo, but it's meaningless in terms of quality and nutritional value. And that's because it's just a regulation term about who is in charge of regulating those specific ingredients. If you consider animals, where we're getting a lot of our nutrients from, for ourselves and for our pets, there are plenty of parts of an animal that humans can't or won't eat, right.
Dr. Kent: Yeah, we either decide that it's not socially acceptable to eat this part of it, or we're vegetarians, so we don't eat any of it, but yes.
Dr. Larsen: Right. Yeah, and I mean, to be fair, the difference is in what we consider food among the things that are edible is arbitrary. There are generational differences. There are cultural differences. There are economic differences. And so a lot of people don't eat organs the way that we used to. Like our grandparents all ate organs, right? And lots of cultures, organs are very popular still. But there's a-
Dr. Kent: Chopped liver.
Dr. Larsen: Yes, right. Liver and onions for Sunday dinner.
Dr. Kent: We didn't have liver and onions, but I loved chopped liver growing up. Sorry. Anyway.
Dr. Larsen: And those organs are very palatable for dogs and cats too. And they have a A lot more nutritional value than muscle meat.
Dr. Kent: Okay, so let's say I go into the store and I go, you know what? This is confusing. I'm just gonna cook for my dog. I'm just gonna feed my dog what I eat at every meal. Is that... an acceptable way to feed your dog.
Dr. Larsen: Yeah, a lot of people are very interested in home cooking for their pets. And formulating homemade diets is something that I spend a lot of my professional career doing. Most of the time, that's because there's a medical need for that, meaning that the patients that we're managing have a combination of diseases where there isn't a suitable therapeutic diet, or the pet has decided that the available therapeutic diets are a no.
Dr. Kent: I.e. they don't taste good to them.
Dr. Larsen: Yes, either because of the underlying disease or the medications that we're giving. We do a lot of things in the treatment and management of disease that affect appetite and sensory aspects of liking and choosing to consume food.
Dr. Kent: Taste.
Dr. Larsen: Yes, of course.
Dr. Kent: Or smell with dogs also, right? Absolutely. Smell is going to be really important for dogs.
Dr. Larsen: Yeah.
Dr. Kent: Sometimes the worst smell, the better.
Dr. Larsen: Yes. We're not always aligned with what smells and tastes good.
Dr. Kent: So let's say I want to feed my dog and I have my oatmeal or toast for breakfast and then for lunch I had some of last night's dinner and then I just split my meal with him. Is that an okay way to go?
Dr. Larsen: Well, small amounts of table foods are fine.
Dr. Kent: No, I mean, if we're just going to feed him like that.
Dr. Larsen: Yeah, so that wouldn't be a balanced diet. So our general guideline is that we don't want more than 10% of the calories to be coming from an unbalanced source. Now, that could be table foods that you're sharing. That could be dog treats. toppers that you're adding to the diet. There's even a lot of calorie-containing supplements like fish oil, for example.
Dr. Kent: I was going to ask you about that later, so we'll get there.
Dr. Larsen: Yeah, I mean, oils are fat and they provide a lot of calories, but they don't provide the full complement of the 40-ish essential nutrients that dogs require. And so it's really important that we're feeding a balanced diet. So when I'm formulating a home-cooked diet that is balanced, I'm making sure that I'm providing supplements to sort of fill in the gaps between what's coming from the base ingredients of the protein and the fiber source, the fat source, et cetera, and what the animal needs. So that's going to require, if I'm using human supplement products, between 4 and 8 different products. You can't just chuck in a multivitamin and consider it balanced. So there's a lot to consider. And as you know, we've done some work looking at homemade diet recipes. And a lot of that has been supported by the school's Center for Companion Animal Health. And so we've done quite a few studies looking at the recipes that our clients have access to, because we were seeing so many people use them and we were pretty concerned about that.
Dr. Kent: So why were you concerned about them? What, like, you know, they're coming from reputable sources, I suppose, either veterinarians or, you know, you find them on the internet. Aren't they good at supporting life? I mean, can't you just formulate a recipe?
Dr. Larsen: Yeah, I think that a lot of people think it's pretty easy. You just mix foods or you can just use a ratio.
Dr. Kent: I'll just go get hamburger at the store and I am seriously. So enlighten me, Dr. Larsen, please.
Dr. Larsen: A lot of those recipes are pretty vague. So maybe they say, Two cups of chicken. Okay, is that light meat? Is that dark meat? Is it thigh, breast? Does it include the bone in the skin? Does it not include the bone in the skin? Is that the raw amount? Is that the cooked amount? How are you cooking it? If you cook it, are you including the drippings or are you discarding the drippings? So as you can imagine, once you start thinking through all those details, there's a lot of different factors that can change what ultimately ends up in the bowl. So the vague parts of recipes were pretty concerning to us. They were also clearly missing sources of important essential nutrients, like there wasn't a source of calcium. And so we looked at this in pretty systematically in a few studies. We looked at 200 dog study, dog recipes in one study. We looked at almost 100 cat recipes in another study. And we found by far very, very few of the recipes that are available online or in books, even if they're written by veterinarians or are in veterinary textbooks, have enough problems that we don't recommend sort of those general or generic recipes.
Dr. Kent: So you mean that they're missing a key nutrient, a key enzyme, a key something that's not going to support life on its own.
Dr. Larsen: Yeah, at least one.
Dr. Kent: At least one.
Dr. Larsen: Yeah, so the study that we did when we looked at 200 dog recipes, we found that about 83% of those were missing more than one essential nutrient.
Dr. Kent: Wow, that's pretty impactful.
Dr. Larsen: Yeah.
Dr. Kent: All right, you've convinced me I shouldn't be cooking for my dog. I should really stick with dog food that's available, commercial dog food, just me. I mean, some people want to do that and that's okay. But it sounds like they should speak to a veterinary nutritionist before they do. So call for help, right?
Dr. Larsen: Yes, that's what we're here for. We're happy to help guide people that want to or considering cooking for their pets.
Dr. Kent: Okay, so maybe we'll put the link in the summary for this episode so they can figure out how they can either talk to you or have their veterinarians request counsel. All right, I'm back in the dog food aisle. I'm reading this. I see there's a nutritional summary statement and I'm happy with it. I see an ingredient list. Who's controlling all this? Who regulates it? Again, I'm a little skeptical because this is, like I said, this is a multi-billion dollar industry.
Dr. Larsen: Pet food is actually pretty highly regulated, especially compared to human food. I think people really don't appreciate the levels of regulation that are going on. So there is some regulation going on at the federal level from the FDA.
Dr. Kent: Oh, so the Food and Drug Administration, who controls everything from drugs to meat and everything, well, that's agriculture, but still, it covers a lot of the food we eat, also covers pet food.
Dr. Larsen: Yeah, absolutely. There are lots of veterinarians that work for the FDA. And as far as pet food goes, their main interests are making sure that pet food is truthfully labeled. So consumer protection in terms of understanding what they're buying, that it's not contaminated with harmful substances. And so the FDA does have the power to pressure companies to do a voluntary recall. They also have the power to do a mandatory recall. So they will respond to complaints. They do have a laboratory network to sort of investigate contaminants and consumer complaints. There's a portal where you can report problems. And then they also have rules related to processing, safe processing, temperature of canning and those kinds of things. The majority of the regulation, though, is going on at the state level. And that's where AFCO comes into play. So some people may have heard the term AFCO.
Dr. Kent: AFCO, can you tell me what that means?
Dr. Larsen: Yes, that stands for the Association of American Feed Control Officials. Now, AFCO is not a regulatory body themselves. They are an advisory body, but their members are made-up of a lot of the state feed control officials. So every state has their own feed control unit at the level of the state government. So in California with the CDFA, the California Department of Food and Ag.
Dr. Kent: And that would cover everything from dogs, cats, to horses, to cattle, to even, you know, all the food production animals.
Dr. Larsen: Yeah, all of all the animal foods. And as you can imagine, there is a lot more focus on livestock in terms of it being a food supply for people and making sure that there aren't drug residues and those kinds, or infectious diseases and those kinds of problems. But so pet food is still regulated at the state level. And so the state feed control officials then will look at what AAFCO is presenting in terms of model feed laws. And so what that means is that every year, AAFCO publishes a book called The Official Publication, and that book has model feed laws in it. And those laws include everything from the nutritional profiles that the diets have to meet in order to say that they're okay for growth or for adults or reproducing animals. They have ingredient definitions, so if a food doesn't have an ingredient definition, you can't put it into an animal diet.
Dr. Kent: Okay, so that helps ensure that it's safe at least.
Dr. Larsen: Yeah, there are definitely definitions for what's allowed to be in pet food and what's not allowed to be in pet food.
Dr. Kent: So you're not like putting melamine in there or something like that as a filler to look like there's more protein than there is.
Dr. Larsen: Yeah, and there's a big focus on avoiding drug residues, of course, either antibiotics or euthanasia drugs and those kinds of things. There's a zero tolerance policy for those contaminants.
Dr. Kent: And obviously for pet foods, that's really essential too.
Dr. Larsen: Absolutely.
Dr. Kent: Yeah. So we think they're pretty safe and we think they're fairly well regulated. You know, it's ,It's really down to then preferences if you want to feed a wet or a dry, if you want to feed one of these refrigerated foods, as long as they've got the nutritional labels on there saying, you know, and it sounds to me like you're going to go pretty well as long as the food's labeled correctly. Are the labels enforced? Do people check them?
Dr. Larsen: Yeah, so that's a good question. A lot of the regulation which is done at the federal and state level is then sort of left up to like the local officials to monitor and enforce. However, so much of the responsibility and that onus to make sure that companies are making safe and healthful pet foods and that they're meeting their claims comes down to the manufacturers themselves. So they have a huge responsibility. It's really important that they have the expertise and the money to engage in a lot of involved quality control, research and development, and all of those other aspects of having a pet food that is safe. So that's why we recommend buying pet food that is made by a large experienced manufacturers, just like when you buy a car or a dishwasher or anything else.
Dr. Kent: So it sounds like it's a lot of self-regulation too.
Dr. Larsen: And they're testing each other's foods all the time.
Dr. Kent: Okay, so that's why you're suggesting that maybe one of the more established companies may be safer than a small boutique one, which may not either have the expertise or may not do the testing they're supposed to.
Dr. Larsen: Yeah, they might not even know what's important. So that the level of expertise is really important. You want to have formulation experts, legal experts, toxicology experts, processing experts on your team, and they should be employees of your company so that you know that you're making a safe and nutritious pet food.
Dr. Kent: So it's all very interesting. And again, it makes it a little bit more complex, right? This is a lot to think about when you're making a diet that's going to be 100% of their nutrition.
Dr. Larsen: Yeah, and unfortunately, there isn't a lot of transparency in the pet food industry because it's so competitive. Companies are pretty secretive about some of the palatants they use to make their food taste good. they want to have that competitive advantage and those kinds of things.
Dr. Kent: I mean, that happens in human food too, right?
Dr. Larsen: Absolutely.
Dr. Kent: Yeah, the secret formula for a drink or something.
Dr. Larsen: Right, or the 11 herbs and spices or, you know, all those things. And so I think that consumers can get sort of lost and they don't understand, how do I look at information and decide, is this just marketing or is this something that's actually useful information? And you're really relying on the reputation of the company. And that's why marketing and the way that marketing interacts with the way our brains work psychologically is such an important part of making decisions about pet food purchasing.
Dr. Kent: I know we're going to run out of time, but over the years, I've seen a number of fads and pet food diets, dog food particular, and people too also, right? Okay, first, raw. I know it's controversial. I've heard the argument that this is what wild dogs and wolves eat. So is it safe? Is it better nutritionally? But enlighten me, Dr. Larsen, enlighten me.
Dr. Larsen: There are a lot of aspects to that. So the fact of the matter is, that dogs did not evolve as hunters. They evolved as scavengers. So dogs have lived alongside people for thousands and thousands of years. The vast majority of the dogs in the world today still live the way dogs evolved, where they're sort of loosely associated with human settlements. They live off our handouts, our garbage dumps, et cetera. They are very good at fulfilling that niche. In fact, they are out-competing some wild canids in some areas, like the Ethiopian wolf is endangered. Dogs are doing very well in that specific setting. And so I think people have this naturalistic appeal to that idea that it is natural, but we don't actually want natural when it comes to our lives or our pets' lives.
Dr. Kent: Why? You know, like, isn't a wolf going to be very similar to my dog? This is my softball question to you.
Dr. Larsen: Yeah, wolves and dogs are pretty similar and we share a lot of the same DNA, just like we do with bonobos and chimpanzees, right? But our goals for our pets are longevity. We want them to live well into their late teens and beyond if possible, right? And lifespans for people and for dogs have been lengthening and lengthening over time because of preventative medicine, infectious disease control, better nutrition, et cetera. From an evolutionary perspective, what would be natural would be to reproduce as early as possible and then make offspring that are better than you for the environment that you're in. And then ideally you would die and get out of the way and stop competing for resources.
Dr. Kent: I don't want my dog going away anytime soon.
Dr. Larsen: That's not what we want for our pets. A lot of people don't want their pets to reproduce. which is probably a good thing. We want them to live a long period of time. We want them to be healthy. So our goals are decidedly not natural for our pets. And that's okay.
Dr. Kent: So natural raw food, where's the problem with this?
Dr. Larsen: Yeah, so the other thing about raw diets is, are they beneficial? Right? So I think that if we thought about it critically, we could agree that they're not natural in a lot of ways. But in terms of them being beneficial, there is no evidence that raw diets are of any benefit. And any benefit that somebody sees when they're using a raw diet is not related to the fact that the meat is raw. It's often...
Dr. Kent: It's not a better coat. It's not these things that people attribute it to them.
Dr. Larsen: Yeah, those are related to the diet is higher in fat probably. So that's why the coat looks so great, right? The diet doesn't have a lot of fiber. That's why the stools are smaller. A lot of owners like that they can identify what's in the diet. And that's just because they're afraid of ingredients because of fear mongering type marketing.
Dr. Kent: So it looks like meat, it looks like carrots are in there.
Dr. Larsen: Correct, yeah. And so the fact that we don't have any specific benefits related to the rawness of the diet per se, we contrast that with the flip side of that coin, which is that we do have some concerns. So a lot of raw diets are not balanced, and that goes for home-prepared raw diets as well as some commercial diets. There are some balanced commercial raw diets, but there are also lots of companies that make raw diets without a complete and balanced claim, and they're sort of aiming for a rotational strategy or not making any claim about how to achieve a raw diet whatsoever. So that's a concern, but that's something that's easy to fix. Balancing the diet is not hard.
Dr. Kent: We just need a veterinary nutritionist.
Dr. Larsen: Right. You need somebody on your commercial team or that's formulating a home prepared diet to balance it. It's not that hard. The harder part is pathogen control. So there's a reason why we don't eat raw meat, right? Sushi accepted, but there are.
Dr. Kent: Steak tatar if you fall into that category, right?
Dr. Larsen: But there's still, you know, for sushi grade fish, it has to be frozen at a certain temperature to control pathogens. Like there's still processes. And so for raw pet foods and for raw meat that's sold in the grocery store that people are feeding at home, we have a lot of concerns about the pathogenic bacteria that are present. And the four that we're mostly concerned about, of course, are salmonella, E. coli, listeria, and campylobacter. Those are the four baddies. Those are the ones that cause a lot of sickness, food poisoning in ourselves. A lot of us have experienced that. You might not know exactly what bug that was that made you sick, but we're all very familiar with that.
Dr. Kent: How often does that happen, though? Is that common? That happens in raw diets or.
Dr. Larsen: It's common in people. There is data on the USDA website that has information for all of those different bacteria and the numbers of hospitalizations and deaths every year that happen from those food poisoning events. And as far as pets go and their exposure to those pathogens, there are recalls regularly for commercial raw diets. There are lots of reports of illnesses. Lots of veterinarians have treated those illnesses. We also know that those dogs, even if they don't become sick themselves, they're passing those pathogens and their feces. And there's a growing body of literature documenting that those pathogens are increasingly antibiotic resistant. And that's a huge concern for us as veterinarians and in terms of our interaction with public health and the fact that we need to have antibiotics as an important tool for human illness.
Dr. Kent: So if you have someone who's immunocompromised at home and they're feeding a raw diet to their dog, they could actually wind up giving themselves a resistant bacterial infection.
Dr. Larsen: Absolutely. And there have been lots of documented illnesses and even death in people that have been exposed to raw diets or the pets that are eating those raw diets.
Dr. Kent: Now let's say, now obviously I am somewhat aware of this and I know that our hospital will not feed raw in the hospital because we're concerned about getting a bacterial, you know, contamination in our hospital that's permanent. So we cannot hospitalize a dog who's got a raw diet now because of the risk. But where do we, draw the line? What if we freeze dry it? I know some places will freeze dry raw, or I've had a client tell me that they buy the raw diet and then they cook it.
Dr. Larsen: Yeah, there are lots of mechanisms that people are trying to establish to make raw diets safer. So freeze drying is one way to do that. And freeze drying is a way to preserve some types of bacteria. And it will stop the active reproduction of the bacteria that are there, but it's not going to result in a sterile diet. We still don't have a pathogen kill step necessarily. And there have been recalls of freeze-dried raw diets. And a lot of treats are actually raw, freeze-dried treats, and owners don't realize that they're raw. And it can be difficult to find that information. I have spent a lot of time calling manufacturers to try and find that out. There's also a method called HPP, which can stand for high pressure pasteurization or high pressure processing. That's the same process that human food undergoes. Like if you buy the cooked pulled pork that are in those like sealed plastic containers or sliced cheese that's on a tray covered in plastic, that same process is subjected to our food. And so that's been used for raw diets as well. But there are some pressure-resistant Salmonella species. Some diets that have been subjected to that processing method still have been recalled for pathogenic bacteria contamination. So does that mean that they're getting contaminated after that step? Does that mean that pet food is not a great matrix for that technology? Are there pressure-resistant organisms? There's still a lot to be worked out. There is some progress in that area, though. So hopefully we can increase the safety of those foods going forward. I don't see that segment of pet food going away.
Dr. Kent: Yeah, what about the grain-free craze, another fad that we've seen? I know that I've seen a lot of over the last few years, especially as an oncologist, there's this idea that a low carbohydrate diet may be better for cancer. So enlighten me again, please.
Dr. Larsen: Yeah, grain-free is a marketing category that's been quite popular in pet foods. And we've been feeding grain-free diets for decades.
Dr. Kent: Wait, so you're calling it a marketing category?
Dr. Larsen: Absolutely.
Dr. Kent: Okay.
Dr. Larsen: There is no nutritional or medical indication for a grain-free diet.
Dr. Kent: Okay.
Dr. Larsen: And so what I mean by that is we have used those diets for a long, time. They happen to be grain-free. So for example, there are veterinary therapeutic diets that maybe use potato or pea or something like that with an uncommon protein source like duck, venison, rabbit, et cetera.
Dr. Kent: I had to feed one to one of my previous dogs who is no longer with us. I had to feed her fish a potato because she had a really bad skin allergy.
Dr. Larsen: Right. And the reason why those diets were developed was because The goal was to try to find a limited combination of ingredients that wasn't very common in the over-the-counter categories that people could just buy at pet stores or grocery stores.
Dr. Kent: Something they hadn't seen before that they're not going to be allergic to.
Dr. Larsen: Right, So it was supposed to be for GI allergies or skin allergies. Okay.
Dr. Kent: Now, I bring you back to grain-free. Okay.
Dr. Larsen: Yeah. So we have all of those ingredients available over the counter now. Grain-free became very popular about 15 or 20 years ago, probably. And again, it's just a marketing category. And so essentially what they did was they replaced the grains in the diet. And grains are just cereal plants, right? So wheat, corn, rice, barley, oats, et cetera. They eliminated all of those and essentially replaced that ingredient with tubers. So sweet or white potatoes usually, or with legumes, pulses. So lentils, chickpeas, green peas, those those kinds of ingredients. And so those diets are not necessarily lower in carbohydrate. They just replace grains with something else.
Dr. Kent: So it's not carbohydrate free. It's just grain free.
Dr. Larsen: Correct.
Dr. Kent: So why did we get this idea that grains were bad?
Dr. Larsen: It's very easy for marketing to demonize certain ingredients. In fact, you don't even have to say that an ingredient is bad. All you have to say is no potato. And then of course, a consumer's response is, well, potatoes might be, must be bad then. It's not that hard. So you're trying to differentiate your product from somebody else's product. And corn was the first scapegoat. So everybody wanted to avoid corn, even though corn provides lots of important nutrients. It's very uncommon to have an allergy to corn, et cetera. The sort of agricultural economics aspect of that is a whole other thing. But from a nutritional perspective, there's nothing wrong with grains.
Dr. Kent: So I know these all formulated out fine. They went through feeding trials fine. Some of them were made by big manufacturers for a while. What was the problem with grain-free? What's the cautionary tale here?
Dr. Larsen: So I think that the problem was that we were suddenly using novel ingredients that weren't very common in the marketplace. So except for soy, most of the beans, peas, other legumes hadn't been really used in pet food that commonly. And then not only did we introduce them to the marketplace, we introduced them in high amounts. Now, some legumes, so lentils, peas, et cetera, soy, they-.
Dr. Kent: All the things I love to eat.
Dr. Larsen: Yes. They have anti-nutritional factors as just part of their natural composition. Plants make 99.9% of the pesticides on Earth, and they are protection from being eaten by herbivores, right? That's what plants do.
Dr. Kent: That makes sense.
Dr. Larsen: It's natural. And so anti-nutritional factors are part of the natural defense system of the plant or the natural sort of structure of the plant cells. And those things can bind up certain nutrients to make them not available. We've known this for a really long time. But what that means is that those ingredients have to undergo processing steps to destroy those anti-nutritional factors and make sure that they are available to whatever animal you happen to be feeding. And so a lot of the diets that were grain-free, we started linking them to a specific type of heart disease in dogs, referred to as DCM or dilated cardiomyopathy.
Dr. Kent: Pretty serious. Could be. that's a life-threatening disease.
Dr. Larsen: Yeah, it's very difficult to find that disease early. And so a lot of these dogs weren't diagnosed until they were critically ill or some of them dropped dead. And then it was found, you know, post-mortem that that's the disease that they had. And this is not a new disease for dogs. It is a genetic disease in certain breeds. And it's a very well-defined clinical entity that our cardiology colleagues have been dealing with for a long period of time. Now, the kind of DCM that we were seeing in these dogs, we think was related to sulfur amino acid status. Now, amino acids, of course, are the building blocks of proteins. There are certain sulfur amino acids that are really important for normal cardiac function.
Dr. Kent: Yeah, I've heard of these before. I'm sure a lot of people have. So yes.
Dr. Larsen: Yeah, and legumes tend to be low in those. Legumes tend to be low in those. So not only do they have these anti-nutritional factors, they also are low in those specific building blocks.
Dr. Kent: So like taurine is the name of one of them, right? And so you're not only are you low in taurine for a good portion of your ingredients.
Dr. Larsen: Yes, so taurine is made from the compounds that are in the legumes. So a dog can make enough, they just have to be able to make enough to meet their needs. And so if there's a limited amount of the precursors and we have a lot of fiber coming from those ingredients as well, then eventually the dog's going to become depleted in those. So this is a problem that we have been trying to figure out what exactly is going on mechanistically. It's probably multifactorial. There have been some people that have doubted it's related to food at all. But one of the important factors about this disease when its diet associated is that it can be reversible. That is not what we see with genetic DCM. It is not reversible.
Dr. Kent: So now I know as a clinician that I test a dog who's on a grain-free diet for taurine and I sent it to your lab actually.
Dr. Larsen: Yes. And not all dogs that have DCM now are deficient in taurine. And partly that's because a lot of the diets have been supplemented with taurine. And so it really masks our ability to assess the dog's ability to make taurine if you're giving the sort of end compound in that pathway. So still a bit of a mystery, but since grain-free diets are not medically or nutritionally indicated, I think that it may be there's no reason to choose that kind of diet.
Dr. Kent: So now we were talking about who regulates this stuff. So this is FDA. So did the FDA get involved? Did they pull these dog foods off the shelves?
Dr. Larsen: Yeah, the FDA was getting a lot of reports through the portal, the pet food complaint reporting portal. And they investigated it and they released a couple of different reports a few different times describing the different diets, the features of the diets and so forth. But because this is such a complex phenomenon and so many different diets were involved, and that said, a lot of the diets that were involved in most of the cases were fed to a very small number of dogs in general. And so compared to their market share, the number of cases that they were seeing was fairly suspicious that it was diet related. But we were never able to identify exactly what the problem was. And so there's never going to be a recall for a diet or a category of diets when we can't identify exactly what the problem is, because we're unable to say these ones are safe and these ones are not.
Dr. Kent: So we didn't test this batch and find there was contamination with a bacteria like salmonella or E. coli. We kind of said, this is associated, but we can't prove it, so the government wouldn't step in.
Dr. Larsen: Yes, correct. So we're still working on this. There are some groups that are looking at potential toxins that are present in some of these ingredients. My lab is working on markers other than taurine to try to identify early if there might be a problem. So I'm hopeful that we'll identify what exactly is going on so that we can have improved formulation of these products. But we still see this disease with some regularity, not as commonly as we were five years ago, but we still see it occasionally.
Dr. Kent: So now this has been amazing and I've now gone 20 minutes over past where I was going to talk to you, but I have a couple more questions. Can we go on?
Dr. Larsen: Absolutely. Love talking about food?
Dr. Kent: I'm actually going to step away from food, but I wanted to ask you about supplements and toppers. So first, supplements, mostly fish oil I was curious about. I mean, I know that fish oil is good for many things, so should I be giving my dog fish oils?
Dr. Larsen: Fish oil is so popular as a supplement now. And the reason why we use fish oil is because we want to enrich the diet with omega-3 fatty acids. So those are the fatty acids that are present in the fatty tissues, mostly of cold water fish. But we do have some really good sources now that come from algae, which is a much better source in terms of environmental sustainability, it's acceptable to vegans, et cetera. So those are really good options.
Dr. Kent: Yeah, it makes your dog's coat shiny. It's what the, you know, the, at least the lure is.
Dr. Larsen: And if you don't mind your dog having a little bit of fishy breath, that's okay too.
Dr. Kent: Fishy breath and maybe some other smells coming out on occasion too. But the, so what are the downsides? What do we have to watch for? How do I choose a fish oil?
Dr. Larsen: Yeah, fish oil dosing is based on what you're trying to achieve. So the nutrients that are coming from fish oil, those omega-3 fatty acids, those are not considered nutritionally essential in adult dogs. They are considered nutritionally essential probably during growth and development because they're really important for neurological tissue development. Once you become adult, though, they're not strictly considered essential, which is arguable. The fatty acid scientists like to fight about this a lot. But we also use them therapeutically. So we give even higher doses sort of for their anti-inflammatory effects. And so many diseases have an inflammatory component that we're often using fish oils for everything from kidney disease, to cancer, to arthritis, to heart disease. And we do have some good data to show that administering fish oil in some of those circumstances and the earlier the better does have some benefits therapeutically.
Dr. Kent: Interesting. So now I know if you go into the grocery store, you can get warning on some of your fish that say, pregnant women shouldn't eat this. And we're worried about things like mercury, heavy metals, and the like, how do I know that I'm not just concentrating it in a bottle and giving them the fish oils I need, but at the same time poisoning my dog with mercury?
Dr. Larsen: That's a huge concern, of course.
Dr. Kent: Yeah, I'd be concerned. I am concerned. So.
Dr. Larsen: Yeah, it's the processing and purification processes that fish oil undergo are highly variable, but it's a really important part of the manufacturing process. So we typically recommend choosing fish oil products from companies that have a firm like distillation process to make sure that it's purified. We want to make sure that they're testing for things like PCBs, dioxins, mercury, arsenic, et cetera. I have done a couple of different studies looking at fish oil for pets and have identified at least low levels of things like arsenic, selenium, which can be become toxic at high levels. We have found some dioxins and some fish oil as well.
Dr. Kent: So how do I, do they publish this on the label? Is that required or do I have to go to their website to see if they have tested for these? And do you have to test each batch? How do I, again, getting back to the, I'm looking, how do I do it?
Dr. Larsen: Yeah, fish oil companies, or manufacturers that make fish oil are using a natural product. So from batch to batch, there might be some variation. Maybe they're using different species of fish in every batch or it's a mixed species of fish.
Dr. Kent: Depending on the seasonality of what's available.
Dr. Larsen: Absolutely, right. The algal sources, so the algae, those are grown in big tanks. We don't have to worry about the contamination.
Dr. Kent: There's no mercury sitting in the bay where they're growing it because they're not growing it in the bay.
Dr. Larsen: Correct. Yes, it's clean and sustainable.
Dr. Kent: Yes.
Dr. Larsen: The labeling isn't necessarily going to tell you about testing and those kinds of things. Some companies do provide links to a certificate of analysis, that's a toxin screening sort of mechanism where they're looking for the common toxins, they're verifying the omega-3 fatty acid concentrations and so forth. So again, just like for pet food, you have to have a lot of trust in your manufacturer. It's important that they're experienced and that they have a good R&D and quality control processes in place.
Dr. Kent: So I should, actually, if I'm going to go buy one at the grocery store, I should go look up that company and make sure that they have an independent lab checking their work because, trust but verify or, using an old term, right?
Dr. Larsen: And talking to your veterinarian about what they recommend as well.
Dr. Kent: Okay, that sounds really important. So you mentioned the word toppers earlier. That's, you know, a term I'm not terribly familiar with, even as a veterinarian. What is a topper and what is it used for? What? What do you mean?
Dr. Larsen: A lot of owners and their pets love toppers. This is a way that we can add some interest and variety to the daily diet.
Dr. Kent: So what's a topper?
Dr. Larsen: Well, just like we were talking about before, we can use things like table foods or treats. Some companies make kibble gravy or other kinds of liquids that you can put on top of your dog's balanced diet.
Dr. Kent: So these are like flavor enhancers or make it more interesting?
Dr. Larsen: Anything that you add to the main diet. So that could be applesauce, that could be canned pumpkin. We use things like honey and syrup quite regularly when we especially need to restrict fat or protein. Then we can leverage sort of the sweet tooth that some dogs have. But like I said, there's also specific products that are marketed as toppers that you can use. I'm always a big fan of using table foods instead of commercial treats as snacks, though.
Dr. Kent: So this is where if I wanted to give my dog some of my dinner, I could actually cut it up, put it on his bowl of food, and make his food more interesting and make me feel better that I'm not home cooking for him.
Dr. Larsen: Yeah, and they love it, right? And we'd like to see our pets enjoying their diet.
Dr. Kent: Food does equal love sometimes, right? It does, it does. Or we at least express it that way.
Dr. Larsen: It's very culturally important to us, and it's important to our pets too. And so the important rule for that, again, we talked about the treat allowance and our 10% rule.
Dr. Kent: Is that calories or volume?
Dr. Larsen: That is percent of calories. So that's a little difficult to quantify. But it's much easier to stay below that 10% rule if you're using things like vegetables and fruits versus using things like cream cheese, peanut butter, meat that adds up really fast because they have more calories.
Dr. Kent: That makes sense. And as we think about calories, I know one of the problems we had, especially in our older dogs, when they may slow down a little bit, same as people, it's hard to keep that weight off. And you're actually even losing your muscle mass as you get older and you're adding weight. It's harder on your joints. It's harder for orthopedics, other diseases, metabolic disease. How do we keep track of this? And we get the older dog who's starting to put on pounds. How do we think about this? How do we approach this?
Dr. Larsen: Prevention is much better than trying to reverse an overweight condition once it occurs. And so having an owner proactively assess their pet on some kind of regular basis. And sometimes I recommend that people maybe that are giving a monthly heartworm preventative or something like that. They sort of use that as their trigger in their brain, I should assess my dog's body weight and body condition. Because changes happen slowly, day by day, and we don't notice them. And then one day you look at your dog and you're like, oh my God, your head is so small. It's actually that they gained weight, right?
Dr. Kent: And it didn't shrink. Right.
Dr. Larsen: And so just sort of doing that proactively and reminding yourself to assess them and then make adjustments as needed. If there haven't been any changes in the diet and you don't think that there's sabotaging their own diet by stealing things or somebody's not feeding them extra things, it might be worth talking to your veterinarian about any significant changes that you notice. If your pet suddenly develops a big belly or suddenly loses a lot of muscle mass or becomes less active pretty abruptly or something like that. It's important to get that checked out.
Dr. Kent: Those are all signs of disease too, right? You know, rapid changes.
Dr. Larsen: Yes.
Dr. Kent: So I now totally blown talking to you for 1/2 hour because we're gonna have to split this one in two now because we're past an hour. So, but something I've noticed and something that, you know, is we get some training in veterinary school about nutrition, but probably nowhere near enough. And I know owners come to their vets to ask them about nutritional questions where, where do you think the state of nutritional education is so that our veterinarians who are helping everyone out in the real world, not just in the ivory tower of the university here, have access to it? I have access to you. I ask you all the time for questions about my patients. So I'm having trouble formulating this question right, but what are the resources out there for people? How do they find out more information and how do we do a better job of educating the public?
Dr. Larsen: I think that's an excellent question. One of my favorite parts of my job is working with veterinarians that are out in the trenches. And I do that through formal consulting, through online websites with other veterinarians. We get phone calls and emails from veterinarians all the time. And sometimes they have a really complex diseased patient that needs pretty high-level interventions. And other times they have questions about a specific brand or a specific marketing strategy. And one thing I'm almost always reminding them of is more than you think you do. I think that veterinarians, and veterinarians are people, and they're just as confused about some of the pet food marketing as pet owners are. And so I'm always reminding them that's just marketing. That doesn't mean anything nutritionally. And I think that's very reassuring to them. And even if they did not get formal, separate courses specifically in nutrition in veterinary school. Nutrition is so fundamental to the management of so many diseases that it's integrated into medicine courses, oncology courses, dermatology courses, et cetera. So they actually get a lot of nutrition. It's just not taught in some schools as a separate discipline. Rather, it's more integrated.
Dr. Kent: So you feel like going to your veterinarian? you should be able to ask your veterinarian about nutrition. And if you ask a question they don't know, they should be able to reach out to a colleague who does.
Dr. Larsen: Absolutely. And I really hope that veterinarians are asking about diet history, that they are looking at body condition and body weights and recording that in records.
Dr. Kent: Body condition. What do you mean by body condition?
Dr. Larsen: That's an assessment of how much fat tissue a pet has. So fat tissue is normal and healthy. You should have a certain amount. But if you start accumulating too much, then we start giving you a higher numerical score on our body condition score system. So it's just a way of us sort of assessing whether a dog is overweight, perfect, or underweight for their individual frame. And I really want veterinarians to feel confident making those assessments and putting those in the record. But a lot of times we sort of I think probably getting away with is not the right answer, but because we have so many good commercial options that supply nutritional needs of pets, we're not seeing diseases that we used to see that often anymore. So things like rickets, other kinds of deficiencies, we still see those with some regularity, but not like we used to. And so we've done such a good job in meeting the nutritional needs of most of the pets that are out there that now it's sort of the pendulums are swinging the other way where we've sort of almost forgotten about it.
Dr. Kent: Wow, this is, you know, obviously this is such a big topic that we're talking about and so important and fundamental for our dog's health. And I realized I've now spoken to you for an hour and I haven't started asking about cats. I'm going to have to ask you to come back and we could do a cat episode. Dr. Larsen: I would love to come back and talk about cats.
Dr. Kent: Good, because I have two cats and now I'm going to tell you I'm standing in the grocery store aisle looking for a cat food and what do we do? So Dr. Larsen, I appreciate you taking the time today and sharing your knowledge and expertise with me and with everyone who's listening to us.
Dr. Larsen: Thank you for having me. I can't wait to come back.
Dr. Kent: Thank you. Okay, bye.
The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan.
S01 E01: Fleas
- Read the Transcript
- DR. LASHNITS: It's probably way more about flea biology than you really want to know.
DR. KENT: No, actually, this is fascinating for me. Hopefully everyone else is enjoying learning about this too, but it's more than I learned in vet school.
Hello, this is Michael Kent. I'm a professor in radiation oncology at UC Davis, and welcome to today's episode of Vetrospective. Fleas. When I think of fleas, I think of these common insects that are also parasites and really are a nuisance. They bite and feed on our dogs’ and cats' blood, which can cause itching, hair loss, and result in hot spots. The itching is annoying and affects their quality of life. In severe infestations in small dogs and cats, in particular, you can wind up with anemia or blood loss anemia. Fleas will also sometimes bite people, and this can transmit disease. So I'm here today with Dr. Erin Lashnits, and we're going to talk to you about this some more. So welcome and thank you for joining me, Erin.
DR. LASHNITS: Hi, yeah, thanks for having me.
DR. KENT: So just a little bit of an intro on Dr. Lashnits here. She did her undergraduate work and master's degrees in biological sciences at Stanford. She then went on to Cornell University for veterinary studies, where she got her DVM degree. And then did an internship in private practice in Brooklyn. Is that right?
DR. LASHNITS: Yep. Yeah.
DR. KENT: And then after completing her internship, she went on to do a residency in small animal internal medicine and her PhD in comparative biomedical sciences at North Carolina State. It's all very impressive. So after completing her studies, she went and joined the faculty as a clinical assistant professor at the veterinary school at the University of Wisconsin. She has over 25 publications in print now and is known for her work in flea-transmitted diseases. So again, welcome, Dr. Lasnitz, and thank you for joining us.
So I'm always curious, I wanted to start out by just asking, why and how did you get into veterinary medicine? You know, why choose VetMed.
DR. LASHNITS: Yeah, good question to start out. I was not one of the kids that wanted to be a vet from the time I was five years old, like my daughter is currently.
DR. KENT: Excellent.
DR. LASHNITS: I wasn't sure what I wanted to do, like as a kid or teenager or even in college, really. I wanted to do science, but I didn't really know what that meant. So after I graduated, I got my master's because I sort of didn't know what I wanted to do. And after I graduated, I was working in a lab at UCSF, actually, doing sort of cancer research, cancer biology, and we worked with a mouse model.
DR. KENT: A woman after my own heart doing cancer work.
DR. LASHNITS: That's exactly right. Yeah. I was more on the chronic inflammation side. We were studying angiogenesis.
DR. KENT: Fair enough. So angiogenesis meaning new blood vessel growth.
DR. LASHNITS: Yes, yeah, It was a cancer research lab. We were just doing sort of the angiogenesis work. But anyway, I was working with mice, helping to sort of take care of the mouse colony where they were doing testing of various different kinds. And I really liked working with mice. And I sort of had this existential, like, I like working with mice, but I really wish that I could help them instead of just using them for research. Like, what if I could help animals? And wouldn't it be cool to be a doctor? But I don't really want to be a doctor for people. But what if there was a job, like you could be a doctor for animals? And I spent probably like six months just wondering about that before it came to me, like, oh, right, there is a job like that. It's a veterinarian; like most kindergartners know about it.
DR. KENT: Yes. It just took you a little bit longer to find it.
DR. LASHNITS: Yeah, it took me a little longer. And so, then I started sort of doing my pre-reqs and working at the San Francisco SPCA and getting all that kind of stuff under my belt and just getting a little bit more experience in the actual vet world. It's like post-college.
DR. KENT: Yeah, so then you became a vet and then you went, I want to be an internal medicine specialist. How did that grab you and what led you to kind of where you are now?
DR. LASHNITS: Yeah, so, having taken sort of a little bit of a winding path to get to vet med in the 1st place, when I came into vet school, I thought I wanted to be a wildlife or conservation type of vet, maybe work at a zoo. So I spent my whole vet school preparing to go do a residency in zoo med. I was really interested in ecology and wildlife and stuff like that. And so I got to my clinical rotations in 3rd and 4th year and spent a couple of rotations at a couple of different zoos and realized that I didn't really like it. Intellectually, it just wasn't really my jam. Like we would do some blood work on a species and then kind of be like, well, this is the first time we've ever looked at blood work on this species. So I wonder if it's normal. We don't know if it's normal or not, right?
DR. KENT: And is there a disease? We don't know. Yeah.
DR. LASHNITS: So that was tough. And sort of in contrast, then I spent just two weeks on internal medicine, small animal internal medicine in the hospital at Cornell during my 4th year, and I loved it. I just, it was like the exact opposite, right? We spent like hours talking about the blood work on every single patient. And I was like, wow, you could really delve into this. Like, we can really find out what's wrong with these pets. We can help them. And so that really kind of scratched that intellectual itch for me. But I didn't go right into like internship residency straight away. I didn't really know what I wanted to do, but I sort of knew I wanted to maintain a research lab of some kind and maybe go back into academia eventually, because that's where I had sort of come from this idea of maybe I would do a PhD. And so I ended up doing private practice and ER and GP for a couple of years after my internship actually and then applying for internship and for a residency and PhD at NC State.
DR. KENT: So then after that, you went to Wisconsin. And so why academia? Why are you staying in academia? Why at the golden palace and not in a private practice? What drives you to be here?
DR. LASHNITS: I actually really liked my time in GP. I spent 2 1/2 years or so as a general practice vet. I really liked seeing sick patients, but like we had, you know, we had sort of urgent care and that kind of thing and it was really fun. It was sort of, interesting to be the first opinion, right? Like somebody would come in with a cat who just like wasn't feeling great and you had no idea. And the extra challenge was particularly for clients that didn't have a lot of resources where you could just like, if you could just do a really good physical and like find the thyroid slip or palpate some enlarged lymph nodes and give them like at least a tiny bit of an answer or a direction that you could say, hey, we can spend not very much money and I can probably tell you what's going on. And maybe how to approach it, how to treat it. So I really liked that. But I also really like research. I really love teaching. I kind of wanted to be sort of having had that experience, I wanted to be kind of more behind the scenes, like kind of contributing to the development of veterinary medicine and veterinary students and curriculum and that kind of thing for the long term. So yeah.
DR. KENT: So now I invited you here because we were teaching a class together. We were teaching a lab on how to do bone marrows. And I was asking you, what your research interests are because you're a fairly new faculty to Davis, right? And so this is how I'm transitioning us back to fleas. And, you know, I know there's a dog flea and I know there's a cat flea and I had this in vet school years ago. So can you just talk maybe a little bit about which is more common on which species? Because it's interesting, right? And Just tell me a little bit more about these real small, annoying creatures.
DR. LASHNITS: They are small and annoying. So what we learned in vet school was dog fleas and cat fleas. And it turns out that actually, like we used to think these are two different species, right? So Ctenocephalides canis, dog flea. Ctenocephalides felis, cat flea. But it turns out that actually probably a lot of them are just C. felis. So when you say anatomy.
DR. KENT: C Felis, what we're doing is we're abbreviating because that's so hard to say.
DR. LASHNITS: Yes, exactly. Nobody wants to have to say Ctenocephaladis felis us over and over again.
DR. KENT: I don't think I can say that once, much less 10 times.
DR. LASHNITS: Yeah, so in general, most of the time when you see a dog with fleas, that dog actually has cat fleas.
DR. KENT: Got it.
DR. LASHNITS: Not dog fleas.
DR. KENT: Thank you.
DR. LASHNITS: And then so also the cat flea, like it's not just for cats, right? It's not just for cats and dogs. It has a huge range of different species that it will jump on, including people. And so it's an interesting sort of thing about the biology of this flea as opposed to some other fleas that are very species specific.
DR. KENT: So it's not like, I know lice are very species specific, right? Like we don't catch pigeon lice, which if you've ever seen them, they're huge.
DR. LASHNITS: Yeah.
DR. KENT: Kind of scary looking. But so fleas can actually cross species.
DR. LASHNITS: Yes, fleas cross species a lot. So if you have cats and dogs in your home, if a cat has fleas, the dog will get fleas and vice versa. And they're the same fleas. They're all going to be C. felis.
DR. KENT: Okay.
DR. LASHNITS: And the ones that bite you are also going to be C. felis.
DR. KENT: So can you tell me about their life cycle a little bit? You know, it's been years since I've looked at this. I know there's larval stages, there's adults, and then they need certain, like, I don't know even what the words are, but we basically need to have certain conditions so that they can complete their life cycle. And maybe we can bring a little more understanding to this.
DR. LASHNITS: Yeah, So there is a life cycle. Basically, the females lay eggs. The eggs hatch into larva. The larva exist as these like little teeny motile like tiny microscopic wormy things.
DR. KENT: And are they on your dog or your cat or are they in your carpet?
DR. LASHNITS: They are in your carpet. The eggs fall off of the dog or cat into the carpet and anywhere else. The pillow, the couch, the bed, your bedding, wherever the animals. And then the eggs hatch, and then the larva. So the larvae hatch from the eggs. The larvae actually eat the flea feces, which we would call flea dirt because it's gross to call it flea feces, but that's what it is. It's just flea poop. So flea dirt is actually flea poop.
DR. KENT: And flea poop is mostly what?
DR. LASHNITS: Flea poop is mostly the blood of whatever the flea was feeding on.
DR. KENT: So the larvae eats your digested dog or cat's blood.
DR. LASHNITS: Exactly.
DR. KENT: They really are parasites.
DR. LASHNITS: Yeah, they're really gross. So the larvae feeds on the flea dirt. And then it forms a cocoon and it pupates. And that is what can persist in the environment for a really long time.
DR. KENT: Like a week or months or a year.
DR. LASHNITS: I've heard stories of potentially like a year, but definitely at least six months or so. And then it will hatch out of that cocoon into the adult flea, like the flea that we know, you know, what it looks like.
DR. KENT: What we can see?
DR. LASHNITS: Yeah, the thing that we are familiar with. It'll hatch, depending on the conditions, it can hatch as quickly as about two weeks. if it's like the prime temperature and humidity and all of that. But it can also last for a really long time. So it can last six months or so in the environment, even up to a year, maybe longer. And what it will do is it will wait basically for a host to come by. The way it senses that probably has to do with like lights and shadows and maybe carbon dioxide. But basically, it'll wait for a new host, and then it'll hatch out into the adult, because if the adult doesn't start feeding right away on blood, it won't survive.
DR. KENT: It won't survive. It needs to have a meal, a blood meal, pretty quickly. Exactly. So basically, the egg is going to release the adult, and that... needs to get a blood meal pretty quickly.
DR. LASHNITS: Yeah. And this is the reason that the life cycle is important in a lot of ways is because the length of it is determined by environmental conditions, but it can undergo the whole life cycle inside. And so this can just live in your house, right? And your house is pretty environmentally controlled, especially in the range that fleas like, which is like 50 degrees Fahrenheit up to maybe like 100 degrees Fahrenheit. So wide temperature range. Usually your house is within that, hopefully, yes, hopefully. And kind of range of humidity, but likes more humid climates. But this is the thing that people will talk about is like when you rent a new apartment, for example, it may have been empty for a few months, but if the last people had fleas, those eggs, or sorry, those pupae are waiting in the carpet, sort of waiting for new hosts to come by for them to hatch and jump onto your dog. And so I'm very paranoid about it now. So I don't like to rent anything with carpet. But I understand it happens. But that's where that life cycle is really important to understand and like why we'll always make sure that we have our pets on their preventatives when we go into like an Airbnb or a hotel or anything like that.
DR. KENT: Yeah, because you don't want those fleas, which fed off another animal's blood, to then jump onto yours. We're going to talk a little bit more about that later when we get into some of the other diseases. But I wanted to jump to the first disease that I always think of. Well, we think of the itch, we think of the bite, we think of that and flea allergy dermatitis and controlling that. But really, you know, that's a symptom in a sense. What about tapeworms? So that's probably the one I think of most. And I know dogs can get tapeworms from fleas. So can you explain a little bit about this? So how do you know if your dog has tapeworms? Do they cause clinical problems? Should we treat infections? And how do we treat them?
DR. LASHNITS: Yeah, so dogs and cats can both get tapeworms from fleas. There's a ton of different tapeworm species. But there is one that's carried by cat fleas. And interestingly, the way that the dog gets, or cat, gets tapeworms from the flea is they have to eat the flea. So it's not spread by the actual flea biting.
DR. KENT: So it's when they're chewing because they're itchy, or cat would be grooming because their skin is itchy, that they're going to actually ingest an adult flea and the tapeworm is in that adult flea.
DR. LASHNITS: Exactly. And then it sets up infection in the dog's or cat's intestines. And then eventually that infection will become patent and the dog or cat will poop out the little proglottids, which are the little segments that look like grains of rice that hopefully you have never seen in your own pets, but maybe you have.
DR. KENT: Maybe.
DR. LASHNITS: But definitely most people have seen in some form or at least pictured on the internet.
DR. KENT: Yes, and if not, you can Google it and make sure safe search is on.
DR. LASHNITS: But generally, they don't cause, unless that's very young puppies and kittens, generally in adult animals, it doesn't cause really severe infections.
DR. KENT: But it is a signal that you actually have fleas. So if you have tapeworms in your pet, that means they have fleas.
DR. LASHNITS: That's right. If you have tapeworms, you have fleas. Which is, in my mind, more concerning because in baby puppies and kittens, you can get a big enough burden that it can really make them sick. They can get impactions and stuff like that.
DR. KENT: Impaction meaning, meaning like it can actually fill up their intestines to the point where it gets like a blockage. Yeah. So that's going to be obviously dangerous and life-threatening. But for an adult, it's usually subclinical, meaning they don't, they're not going to get too sick from it, right?
DR. LASHNITS: Yeah, maybe like a little diarrhea, maybe a little bit of like irritation back there. but generally not too sick from it.
DR. KENT: And normally when you go to the vet, because you want to check for parasites, you usually do something called like a fecal smear or fecal flotation, and they'll look for them. Do they usually find the tapeworms then, or is it more that you've got to look for those grains or rice?
DR. LASHNITS: Yeah, it's a good question. There's actually been a lot of research done more recently on like how do we actually diagnose tapeworms and are they being underdiagnosed because your typical fecal float that your vet would regularly do to check for other parasites is not very good at picking up tapeworms. And so a lot of the time... And I saw this when I was out in general practice. We would have patients coming in because people saw the segments in the feces.
DR. KENT: And not everyone looks at their dog's poop. Hopefully if they're out walking their dog, they're picking it up, being good, responsible pet owners. But in your cat, you may not notice it either, right? Unless you see it in the litter box. But mixed with the litter, it may be hard to see.
DR. LASHNITS: So some of the companies have now developed more sensitive screening tests and they're showing that maybe even higher numbers of cats and dogs carry tapeworms than they previously thought using like PCR and stuff like that. So if it's something that you're worried about, it is now easier to test for. But also we know that like if you can clear the fleas, then you can help clear the tapeworms. And if you don't clear the fleas, then it doesn't matter how much deworming you do, the tapeworms are coming back.
DR. KENT: So and then our standard treatments for tapeworms, prevention, and then I know there's something called droncit that we use, right.
DR. LASHNITS: Yeah.
DR. KENT: But now is it, it's more a matter of treating the infestation than actually worrying about the tapeworms themselves.
DR. LASHNITS: Yeah, I think similar to how we think about some of the things on like a 4DX snap test being a signal that like your dog gets bit. 4DX snap test is a test that looks at four different vector-borne diseases. Three of those are tick-borne diseases.
DR. KENT: So vector-borne meaning that the animals, our dogs, our cats can catch them from getting bit by a flea or a tick and it transmits disease.
DR. LASHNITS: Yeah, exactly. So like things that are transmitted by sort of insects that bite. And we think about that's like a blood test that we would do as a screening test for your cat or dog. And sometimes that result is more a signal that, hey, you have exposure to ticks here, as opposed to something that, oh my gosh, we have to treat this disease right now. So I think of tapeworms sort of like that, as if you're seeing tapeworms, yeah, we should do some deworming and make sure that those are covered. But also it's a signal to me that you have a flea infestation and probably need to think about that.
DR. KENT: So yeah, well, the tapeworms gross, having the fleas can actually be pretty gross and more of a problem, too. Yeah, right. So, what other infections can dogs and cats get from flea bites? So, why do we worry about it if we have... some itching, which is annoying, and we have some tapeworms, which really aren't that big of a clinical problem, even if we really don't want to see them. But why is this an interesting parasite? What else can they cause for dogs and cats?
DR. LASHNITS: Yeah, so this is actually where most of my research falls, is trying to figure out really what all things fleas carry and can transmit, and what things that are, what diseases that are relevant to dogs and cats and people cat fleas carry and transmit. Because you can imagine, you can test cat fleas for different types of bacteria or pathogens. And sometimes you'll find those in the cat flea because the cat had it, right? So because the cat flea drinks cat blood, sometimes there's just some pathogens in the flea because of the blood inside the flea. But that doesn't mean the flea is necessarily able to transmit it to the next cat or dog or person that it bites.
DR. KENT: So does a flea bite one dog or one cat in its lifetime? Or does it jump on and off and maybe go between your pets? Maybe goes from your cat to your dog? I have a dog and two cats.
DR. LASHNITS: Yeah. So the sort of conventional wisdom is that once a flea, it like jumps onto a host, it pretty much stays on that host because there's a lot of blood inside that host and it doesn't really need to leave. That can change with probably like the density of infection. Like if you have a so, many fleas, some of them will just be jumping off looking for a better home.
DR. KENT: The little kitten that's brought into the hospital that has 1000 fleas on it and it's so anemic, it's gonna die if we don't get those fleas off it. That's what you're talking about. Yeah.
DR. LASHNITS: And then also they seem to respond to like temperature. And so I don't know if you've experienced this, but a lot of vets have experienced when you anesthetize those animals.
DR. KENT: Yes, definitely.
DR. LASHNITS: And whether it's a reaction to the anesthesia or the patient getting cooler, but when you anesthetize for like a spay or a neuter, the fleas will start to jump off.
DR. KENT: Yep, they're abandoning ship. They think this is not a good host anymore.
DR. LASHNITS: So that can probably happen too. And that's when they would jump onto whoever is nearby and try to find a new host. And then another question that is sort of an open question in flea biology and disease transmission is whether fleas can pass pathogens from the adult flea to the egg.
DR. KENT: And then the pupa and then the next.
DR. LASHNITS: And the larva and the pupa. And so interestingly, the larva that eats the flea dirt, eats the flea poop, right? That flea poop is the animal's blood digested through the flea. And so that's one of the theories as to how fleas might maintain infection throughout their life cycle is not so much that the mom flea passes it to the flea egg, but rather the mom flea is infected with whatever pathogen it is. And then as the larva drinks or eats the flea poop, that's how it gets infection through the life cycle.
DR. KENT: Interesting. It's a kind of unique pathway that we don't see a lot in nature, right?
DR. LASHNITS: Yeah, it's very unique, and actually, fleas are particularly unique. It's probably way more about flea biology than you really want to know.
DR. KENT: No, actually, this is fascinating for me. Hopefully everyone else is enjoying learning about this too, but you know, it's more that I learned in vet school.
DR. LASHNITS: Fleas are different from a lot of other blood sucking parasites because they're such constant feeders. So if you think about a tick, a tick will feed maybe like three times in its whole life.
DR. KENT: Yeah, it engorges and gets really big. Everyone's seen that engorged tick before.
DR. LASHNITS: Yep, and that's done and it molts and it goes to a different life stage. But fleas, they will feed, they will bite and they'll drink some blood and they'll bite again and drink some blood and its sort of constant and they're constantly drinking blood and pooping and drinking and pooping.
DR. KENT: Which is why we see so much flea dirt on our pets. Or if you've ever bathed an animal who has a lot of fleas and literally the flea poop or the dirt looks like blood again when it rehydrates.
DR. LASHNITS: But that's one of the things that helps the flea sort of maintain, it's like one of the things that contributes to flea immunity. So the flea not getting infected is that there is such a like flow of blood through the GI tract. And so pathogens that are transmitted by fleas have to have developed a way to stay inside the flea despite this constant feeding, which is why some of them have developed the potential to make biofilms, which contributes to disease within.
DR. KENT: So a biofilm, will you explain what that is?
DR. LASHNITS: Yeah, oh gosh, I'm probably not the person to explain biofilms, but essentially what it is like instead of bacteria sort of floating free in solution, they make like a little film of almost like what you could think of as like algae.
DR. KENT: So almost its own environment.
DR. LASHNITS: Yeah. And so they can do that sort of on the epithelial walls of the gut of the flea. And so then it doesn't, the bacteria wouldn't get like excreted out right away as the blood is flowing through the GI tract of the flea.
DR. KENT: So now I ran you down a rabbit hole, but really I was wondering like what other infections can dogs and cats get from fleas.
DR. LASHNITS: Yeah. So major tangent.
DR. KENT: I'm really good at that.
DR. LASHNITS: That's okay. So the biggest infection that we think about as flea born is Bartonella. Bartonella henselae being the main one.
DR. KENT: And that's a type of bacteria, right?
DR. LASHNITS: That is a type of bacteria. It's cat scratch disease or for those of us that are of the right age, cat scratch fever, which they did rename for the medical version because of the Ted Nugit song.
DR. KENT: Yes, I was going to say because of the song.
DR. LASHNITS: You can get the sound, the sound folks to put in cat scratch fever in the background.
DR. KENT: Maybe, but I don't know. We probably would have to.
DR. LASHNITS: Can't afford it.
DR. KENT: No, we have no budget.
DR. LASHNITS: For the $0.
DR. KENT: Zero dollars. Standard veterinary medicine.
DR. LASHNITS: Yeah. So yeah, cat scratch disease, which is Bartonella henselae, is sort of canonically, sort of prototypically transmitted by cat fleas.
DR. KENT: So it's not actually the cat scratching you, but if they scratch you and they have had fleas that can transmit it, how does that work?
DR. LASHNITS: Exactly. So the reservoir host is the cat. So the Bartonella henselae lives in the cats, usually bloodstream. But it's not very often that the cat's blood would mix with your blood other than in situations where the cat's blood is being sort of taken out of its body by the fleas, right? And so in a cat with fleas, there's all this flea dirt around. And the flea dirt is actually...
DR. KENT: So there's partially digested cat blood basically sitting on the surface of the cat.
DR. LASHNITS: And so it's infected. Yeah. So this cat's scratching all the flea bites that it has. And then if you get scratched by that same cat, it inoculates the infectious.
DR. KENT: So it's almost like a vaccine of the badness. You know, it's basically a needle. You've seen sharp cat nails before. And so they can just inject the…
DR. LASHNITS: Yep.
DR. KENT: So now everyone wants to treat their flea, their cats, because you don't want flea poop made of your cat's digested blood getting injected into you.
DR. LASHNITS: Exactly.
DR. KENT: So and then what does it cause in people? So this is actually a one health issue. This is a zoonotic infection and zoonotic infection means something that can be transmitted from an animal to a human. So this sounds important. So What does it cause in people?
DR. LASHNITS: Yeah. So cat scratch disease is really a disease of people. It was discovered in like the 1990s or so, mainly because of the HIV epidemic.
DR. KENT: So immunocompromised people where infections are worse.
DR. LASHNITS: Exactly. It was much more common to see systemic manifestations of Bartonella henselae infection in people with HIV that were immunocompromised.
DR. KENT: That's why for a while, human physicians were telling people to get rid of their pets, even though they were so important. for your well-being and maintaining your quality of life and that you have these connections while you're going through such a horrible disease that they're saying you can't have your pet anymore.
DR. LASHNITS: Yeah. And at that time, we didn't really understand that it was flea born necessarily. And so there wasn't, yeah, so they're like, really, all you have to do is make sure that you don't have fleas on your cat. Your cat's fine, as long as you're not sort of taking blood out of your cat and putting it into your own arm. Yeah, or get rid of the fleas so they're not infected with this anyway.
DR. KENT: So what disease does it actually cause in people?
DR. LASHNITS: So in immunocompetent people, often it is sort of a self-limiting febrile illness, meaning you get a little bit kind of just general sick, right? I don't feel that good. I have a fever, maybe big lymph nodes, and those would be lymph nodes.
DR. KENT: Kind of flu-like.
DR. LASHNITS: Kind of flu-like. Usually not super respiratory, so you're not going to get like a stuffy nose, cough, that kind of thing, but just like that, like, I can't get out of bed and large lymph nodes where usually near where the inoculation was, right? So if you got scratched on the arm, it might be the lymph nodes in your armpit that get big, that kind of thing.
DR. KENT: Got it. And then they'll go down after time. You're going to clear this.
DR. LASHNITS: Yep. And in a lot of people, it goes away on its own. In a lot of people, you get treated with antibiotics and that helps it go away faster.
DR. KENT: Yeah, you feel a big lymph node, you see the scratch, you go to your. I was going to say your vet, but you go to your physician. Go to your vet, go to your physician, and they're going to treat you for it.
DR. LASHNITS: Yeah. But then there is a small subset of people, even people that don't have existing immunocompromise or aren't on medications that change their immune system or anything like that, where they can either get chronic infection or they can get these more atypical manifestations. And that can look like lots of different things.
DR. KENT: So hard to diagnose.
DR. LASHNITS: Very hard to diagnose. It can, the main thing that we're worried about is there's reports of it causing neurological illness. And then it can cause…
DR. KENT: Neurological illness like mental health issues or schizophrenia or seizures.
DR. LASHNITS: I know there's all. really in the very early stages of knowing what kind of things we might actually see, but definitely sort of like meningitis, encephalitis has been reported.
DR. KENT: So swelling of the covering of your brain, swelling of your brain. Now, I don't want to scare people because we don't want people getting rid of their cats. Again, you said we just need to treat the fleas to make sure you can't get this. So What about, I know there's also rickettsial diseases, rickettsial bacteria diseases. I think that's something else that we know not enough about.
DR. LASHNITS: Yeah, definitely. So there is a flea-borne rickettsia. Rickettsia is the type of bacteria that causes typhus, which is not something we think about very commonly in the US.
DR. KENT: Kind of like plague, which I know we occasionally come up with, but that's flea transmitted as well.
DR. LASHNITS: Plague is definitely flea transmitted.
DR. KENT: We'll get to that in a minute.
DR. LASHNITS: We'll put it in plague. There's so many. So yeah, so typhus is caused by a Rickettsia species, but there's also another one that is spread by cat fleas specifically, which is called Rickettsia felis. We just don't know very much. Yeah, felis for cats, yeah. We just don't know very much about it. It's been reported to cause similar sort of like febrile illness. but kind of non-specific and really only recognized over the past maybe 5 or 10 years with PCR.
DR. KENT: So something we need to do a lot more work. So PCR being a diagnostic test we use to basically identify things.
DR. LASHNITS: Yeah.
DR. KENT: And then, so we need more research in this area.
DR. LASHNITS: Yeah, definitely. I think one of the big open questions is in terms of any of the pathogens or any of the diseases that fleas carry is are they carrying them but can't transmit them? Or are they carrying them and can transmit them? Like we know for Bartonella henselae, they're carrying them and they can transmit them.
DR. KENT: Yeah. Like your cat scratch disease that you were talking about. Exactly.
DR. LASHNITS: Yep. And then are there things that are less common? Because Bartonella henselei, very common in fleas. Even Rickettsia felis, some of the other flea-born Rickettsia, is very common in fleas. But are there things that are less common where maybe it only crops up in certain geographic areas? or certain climates where we don't see it like spread across the whole United States, but maybe only in certain areas where fleas are causing transmission of certain bacteria.
DR. KENT: From animals to a human they happen to bite.
DR. LASHNITS: Yeah, because again, we know that the cat flea is an indiscriminate biter. It's going to bite anything it jumps on. And so if it jumps on a cat and a person, it'll bite everybody. And if it jumps on wildlife, it can be a source of transmission to wildlife, not just to the cats and dogs that it bites, but also potentially to them.
DR. KENT: So in our free-ranging cats, our community cats, our feral cats, whatever you'd like to call them, is this a bigger problem because there's not flea control?
DR. LASHNITS: Yeah, definitely. I would say so. And that's the population of cats that we've mostly studied in my lab is free-roaming cats, right? Cats, whether they're owned or unowned, but that have essentially like free access to roam where they want and often limited access to veterinary care, meaning they're almost never on flea preventatives and definitely not year round. And maybe sometimes they'll get one here or there when the flea burden is really high or something like that.
DR. KENT: So how do you study that if they're free roaming, if they're out there in the wild and they're not coming in for veterinary care? Like how do you go about that? Or how do you want to approach this problem?
DR. LASHNITS: Yeah, it's a tough nut to crack, really. So I've had really nice success with working with some of the trap, neuter, return organizations. So these are nonprofits that basically are dedicated to improving the lives of these free-roaming cats by giving them at least a little bit of access to veterinary care and often also by spaying and neutering them.
DR. KENT: Trap, neuter, release.
DR. LASHNITS: Exactly, trap, neuter, release. So they know that if they just remove cats from where they're living, new cats will come in and live there. There's plenty of cats in the world. And so they'll keep these sort of stable colonies and sometimes vaccinate them for rabies, try to spay and neuter a large majority of them so the populations don't skyrocket. So we limit the sort of the ecological downstream effects of these cat populations and essentially help them live better lives. But then where I come in is that when they get trapped and neutered, we can comb them for fleas and look at what fleas they're carrying, how commonly they're carrying those fleas, and…
DR. KENT: What pathogens are in the fleas. What's your plans to expand your research in the future? What do you want to do?
DR. LASHNITS: Yeah, well, as you said at the beginning, I'm new here to Davis.
DR. KENT: Welcome, we're glad to have you.
DR. LASHNITS: So I was previously at University of Wisconsin. We were working on trying to sample fleas from all continental United States. This is like sort of a really basic epidemiology problem in that we don't even really know how common fleas are amongst cats or dogs that don't go to the vet across the whole country. And so really just trying to define sort of like, are there places in the country where we really don't have fleas? Because you'll hear that, oh, we don't have fleas here.
DR. KENT: I've had people tell me that and then I see the fleas on their animals.
DR. LASHNITS: Yeah, exactly. So trying to define if there are really places where it is just too dry, essentially, for fleas. But we also know that fleas can maintain their entire life cycle indoors. And so pretty much wherever there are people with pets, there are going to be fleas. But we're also trying to kind of map and figure out the burden of disease for these different diseases that the fleas carry across the country. Previously, I've been doing this working with these community organizations like Trap, Neuter, Return and different shelters and that kind of thing. And in the future, I'm really hoping to expand that to more of a citizen science type of project because the cats that even the cats that come into trap, neuter, return are seeing the vet a little bit, right? And the place where I'm really interested in looking is places where we really don't even have any veterinary care or for owners that don't have the opportunity to take their pets, right? They're not necessarily free-roaming cats, they're owned cats, but they may not be on regular fleet preventatives and looking at the potential for disease and zoonotic disease in those pets.
DR. KENT: So what are the clinical implications of, say, a Bartonella infection in a cat. Does a cat become ill from that?
DR. LASHNITS: Yeah. Does a cat become ill from Bartonella? So what a good question.
DR. KENT: Or a dog.
DR. LASHNITS: Yeah, or a dog. So in fact, this is one of the things where I can't lump cats and dogs together. So starting with cats. So cats are the reservoir species for Bartonella henselae. Bartonella henselae is one species of Bartonella that's sort of bigger type of bacteria.
DR. KENT: So we've got one group of bacteria and you can have different types of bacteria within that group.
DR. LASHNITS: Exactly. There is over 40 species of Bartonella that have been discovered now since the 90s or so when we started figuring this stuff out. And so probably more than one use cats as a reservoir, but you know, not all 40. And so there can be infections in cats that are not with Bartonella henselei, right, that are with other species that are meant to be in, say, a dog or a cow or a goat, and then they infect the cat, and that can make them sick. We also know that there are species of Bartonella that have the reservoir in people. And that actually does make people sick. Those are not zoonotic ones. They're just like transmitted person to person.
DR. KENT: There ours.
DR. LASHNITS: Yeah. But they make people sick. And so, because we know that, we can also guess that the species that are sort of native to cats also sometimes make the cat sick.
DR. KENT: And again, flu-like.
DR. LASHNITS: Various different things. Definitely can be fever, can be sort of associated with the immune mediated diseases that we think about, like anemia or low platelet count or things like that. In cats, it's a little bit hard to define because so many of them just carry it without any symptoms.
DR. KENT: And we don't know yet.
DR. LASHNITS: And we don't know. Dogs is a different story. So in dogs, the main manifestation that we see with Bartonella infection is infection of the heart valves. So something called endocarditis.
DR. KENT: And so that was going to cause a murmur then because the blood flow changes.
DR. LASHNITS: Yeah, And it's Bartonella, various species of Bartonella are probably one of the top causes of endocarditis in dogs. And so if you have a dog that has endocarditis, it's a good chance that it could be Bartonella.
DR. KENT: So inflammation of the heart. “It is” always means inflammation, right? So, of the heart valves.
DR. LASHNITS: Yeah.
DR. KENT: So you've convinced me over this last 30 minutes or so that fleas, you know, we don't want to panic, but fleas, fleas can be dangerous. So What's the best way to protect our dogs and cats from fleas?
DR. LASHNITS: Yeah. The happy news is that since the past maybe 20, 30 years, it's gotten way easier. So there are tons and tons of products out there that are actually really, really effective at preventing fleas and treating fleas. The thing is that you have to use them. And use them regularly. And it kind of, so having no sort of corporate sponsorship whatsoever, to me, it doesn't really matter what you use. There's a lot of less expensive options. There's a lot of very expensive options. There's a lot in the middle. All of them are pretty effective as long as you use them as you're supposed to. So if you're supposed to give it once a month, give it once a month. If you're supposed to replace a collar after six months, replace it after six months. and do that regularly. And we've done studies in using a lot of these different products to show that we used to think you had to treat the environment, meaning like do like flea bombs for your house, right?
DR. KENT: And vacuum.
DR. LASHNITS: And vacuum and go crazy with like all of these like pretty horrible chemicals for your house. In fact, we probably don't need to do that as much as we used to think, but we do need to treat our animals more sort of diligently.
DR. KENT: You break the life cycle, if you kill the flea, then it's not going to have the pupa larvae.
DR. LASHNITS: Exactly.
DR. KENT: And a new adult.
DR. LASHNITS: And the fleas, the eggs will, the eggs and then the larva and then the pupa will sit in the carpet, right? Or sit in your house or sit in the pet's bed. And they'll come out when the pet is now not protected. And so if you can get them protected for months at a time, it does break that life cycle.
DR. KENT: So you should treat year-round regardless of what it's like outside, because inside its nice and warm.
DR. LASHNITS: Exactly.
DR. KENT: And let's say you are going to move into that apartment or the new house and there's carpet down. Then should you treat the environment?
DR. LASHNITS: You know, it's a good question. I haven't. Really, and I don't think many people do. I think that really the important thing in that situation is to make sure your pets are protected before you get into that environment, right? So whether that's like doing the spot on or putting the collar on or whatever it is, do it before you actually enter the environment. So you just don't even have it as an option.
DR. KENT: There's no life cycle to happen then.
DR. LASHNITS: Yeah.
DR. KENT: This has been great. I really appreciate it. And one more question. Is there anything I should have asked you? Was there something big I missed? I mean, I'm not a flea expert, and now I feel like I'm more of one, but that's still…
DR. LASHNITS: No, but we should talk, go back and talk about plague.
DR. KENT: Plague, yes, we brought up earlier. Thank you. So I know plague happens even here in California. It happens up in around Tahoe, the foothills, right? So plague is also transmitted by fleas.
DR. LASHNITS: Plague is transmitted by fleas. Generally out in the environment, like the case in Tahoe this year, that would probably not have been a cat flea. That's going to be wildlife and wildlife flea cycle. But it can infect cat fleas and it regularly infects cats. Because cats interact with wildlife in predatory ways, the thought is that basically the cats and or their fleas can get infected and that's how the transmission can get back to people from these little like ground squirrels or prairie dogs or whatever it is that's out in the environment that is the reservoir for plague and this usually happens in the Four Corners or places like Yosemite, Tahoe, that kind of thing.
DR. KENT: So this is not something, we don't want plague coming back. That was one of our old pandemics, right? We don't want plague coming back. So another reason to treat our dogs and cats and particularly cats who can come in contact with wildlife.
DR. LASHNITS: Yeah, and especially if you have outdoor cats in those places, it is actually really important to keep them on monthly preventatives because if those cats bring back plague, like you do not. I mean, we can treat it with antibiotics, but man, you don't want to get it.
DR. KENT: No. Something I don't want, that's on my list of things I don't want, is plague. We learned that in the Middle Ages quite well as a species.
So, Erin, Dr. Lashnits, thank you so much for joining me today. It's been a lot of great information. I really appreciate you taking the time for me and for our listeners. So we've taken a deep dive into fleas and hopefully we've convinced you we should avoid them.
DR. LASHNITS: Thank you so much. Thank you.
DR. KENT: All right. The Vetrospective, as with life, takes a village. I want to thank those who suggested I start this project and everyone who has encouraged and supported me along the way. Particularly, I want to thank our producer and director, Danae Blythe Unti, Nancy Bei, who is our program coordinator, our sound mixer, Andy Cowitt, and theme music was composed and produced by Tim Gahagan. Thank you all, and we'll see you next time.
Listener Feedback
"Hi! I am the owner of Dogtopia of Davis (and a retired hospital/clinical pharmacist). I greatly appreciate your evidence-based podcast, one that I feel confident to recommend to our pet parents and staff. Extremely well done! Thank you!"
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"The episode on Vaccines dispelled so many vaccine myths that I’d heard bandied about! Thank you Dr. Kent and Dr. Sykes!"

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Austin, TX
S01 E12: Research Director to Director
Research Director to Director
S01 E11: Raising Orphan Kittens
Raising Orphan Kittens
S01 E10: First Aid
S01 E09: Osteosarcoma
S01 E08: Feline Infectious Peritonitis
S01 E06: Dog Genetics
S01 E05: Cancer Immunotherapy
Cancer Immunotherapy
- Demystifying Cancer Immunotherapy for Lay Audiences (Dr. Brady acknowledges Kiara Ellis and Dr. Christopher Pennell for their article, Demystifying Immunotherapy, which played an important role in shaping her approach to teaching this subject.)
Demystifying Cancer Immunotherapy – Pub Med Central; National Center for Biotechnology Information
Immunotherapy is now mainstream. Advertisements are ubiquitous in print and visual media for immune based-therapies for various conditions and diseases. Smaller companies that develop novel immunotherapies are often quickly acquired by larger companies. More and more clinical trials are open for immune-based therapies, particularly for immune checkpoint blockades. As such, immunologists need to engage the public in conversations about the strengths and limitations of immunotherapy, and the necessity of research in propelling the field further. In this article, we discuss approaches we have taken to convey key concepts in immunology and cancer immunotherapy to non-scientists and health care professionals without expertise in immunology. Although the devil is always in the details, basic concepts in immunology and immunotherapy can be readily conveyed using stories and analogies, some of which we present here.
Keywords: cancer, community, engagement, immunotherapy, outreach
Introduction
The need to inform the public about immunotherapy is more important than ever, as immunotherapy is now a key driver of cancer care and precision health. Here we describe community outreach approaches in immunology and cancer immunotherapy we developed for the Masonic Cancer Center (MCC), an NCI-designated comprehensive cancer center at the University of Minnesota.
Know Your Target Audience
Time is precious. Don’t waste it by giving the audience a “one size fits all” rote presentation or one you would give your peers. Identify topics that are likely of greatest interest to your audience by asking representatives beforehand what their most important issues or questions are. Meld your expertise with the needs and background of your audience and tailor the presentation specifically to them. The audience should leave with actionable knowledge and the belief that their time was well spent.
Our discussions of immunology basics don’t differ much between disparate ethnic groups but our discussions of how to apply immunology do. These are tailored to the needs of the group. For example, cervical cancer rates are higher for American Indian, African American, Hmong, and Hispanic women in Minnesota than for others (1–3). In meeting with these groups, we often focus on how vaccines work, how vaccination against human papillomavirus (HPV) reduces the risk of cervical cancer, and the need to increase cervical cancer screening for early detection and a subsequent reduction in cancer mortality (1).
Be aware of the audience’s range of knowledge in science and medicine. If you are updating health care workers on checkpoint blockade therapy or chimeric antigen receptor-transduced T-cells, you can assume a baseline knowledge of the immune system and focus on the specific strengths and limitations of these therapies. If you are speaking to a broad audience, assume an eighth-grade average reading level and a cursory knowledge of immunology and cancer (4). We developed a series of animated videos that includes Cancer 101; this describes cells, how cancers can form, and how to minimize risks (5). Because this video is appropriate for both adult and youth audiences, we find it useful to show at the outset of presentations.
Maximize visuals and graphics on slides while minimizing text. Use analogies, simple language, and avoid jargon whenever possible. When it is not possible to avoid a technical term, define, and explain it clearly before weaving it into your story. Know the physical layout of the venue in which you will speak. This includes its audio and visual equipment, lighting, and acoustics.
Engage the Audience
Consider using experiential activities accessible to broad audiences. This will provide participants who learn by visual, auditory, and kinesthetic methods opportunities to access and retain the information. We invested in wireless polling devices that allow the audience to respond to questions posed by the presenter in real time. This permits the presenter to gauge the audience’s readiness to move on to the next section. Because these data measure impact and collect information anonymously in a non-threatening way, we derive information from communities less inclined to respond to surveys.
What follows is the story we typically tell adult, lay audiences about cancer immunotherapy. This is not meant to be an inclusive review; rather it is one example of how to explain immunology and cancer immunotherapy. We focus on recent advances in T-cell based immunotherapy because these are more topical than well-established monoclonal antibody-based therapies such as Herceptin for breast cancer and Rituximab for B-cell lymphomas (6, 7).
Immune Activation
We begin by describing how molecules, cells, tissues, and organs in the body work coordinately in systems to achieve particular functions. Most everyone is aware of the digestive system, so we begin there by saying the digestive system processes food and absorbs nutrients and water. People are generally less aware of how the immune system functions, so we start by saying the immune system maintains homeostasis throughout the body. When that balance is perturbed by injury, infection, or disease, the immune system is activated. Under normal physiological conditions in a healthy individual, an activated immune system restores homeostasis by eliminating the infection, healing the injuring, or eradicating the disease; the immune system then itself returns to homeostasis. What flows naturally from this introduction are discussions of what turns on and off immune responses.
We show pictures of red and white blood cells and note that white blood cells are part of the immune system. White blood cells become activated and start an immune response when their receptors signal that an infection/injury/disease has occurred. At this point we define a receptor. We show an animated slide that likens receptors and the signals they deliver to the electromagnetic waves received by home satellite dishes and the resultant images they relay to monitors. The external signal received by the receptor/satellite dish is conveyed to the cell/living room via an internal signal cascade/cable network. Physiologically, receipt of this internal signal leads to a change in the white blood cell’s activity and the beginning of an immune response. Questions that logically follow this description include: what are these immune-activating signals, where do they come from, how are they recognized, and how do they mediate changes in cell function?
We next note that signals indicative of an infection typically come from the pathogen itself and so are externally-derived. Before going further, we define pathogen as a disease-causing entity. Collectively pathogen-associated molecules that induce immune responses are called stranger signals and include molecules we cannot make ourselves. In contrast, danger signals are internally-derived molecules our bodies make in response to tissue injury or disease. Danger signals are not normally accessible to the immune system but are released when a cell is damaged or ruptured or stressed. Stranger and danger signals typically indicate something deleterious has occurred that requires an activated immune system to resolve. The receptors on immune cells that recognize stranger and danger signals have coevolved with the cells’ abilities to contain or eliminate physiological insults (8).
The immune system has a spectrum of molecular and cellular mechanisms that maintain homeostasis. Innate immune responses reside at one end of the spectrum and acquired immune responses at the other. Innate immune responses are elicited by stranger and danger signals, cause inflammation, and recruit leukocytes that can non-specifically eradicate pathogens. That is, innate responses can eliminate groups of pathogens but do not distinguish between individual pathogens within the group. Innate immune responses also trigger acquired immunity; these responses take longer to resolve infections because pathogen-specific immune cells are initially present at low frequencies (≤10−5) and take time to expand to sufficient numbers to control the disease (9). Acquired responses are specific to molecules unique to the disease-causing organism. The advantages of acquired immune responses include this specificity and long-lived memory responses to prevent recurrent infections of the same pathogen. The net result is that activated white blood cells can destroy invading bacteria, kill virally infected cells before viruses are released, and eliminate nascent tumors.
Immune Surveillance
Immune surveillance refers to the immune-mediated elimination of nascent malignancies before they become clinically apparent. This occurs constantly and perhaps is the last barrier a cell must breach before becoming malignant (10, 11). By definition, cancers have escaped immune surveillance. And this stymied the field of cancer immunotherapy for over a century. Immunologists long recognized the immune system could be exploited to treat cancer because of four key characteristics: specificity, potency, memory, and adaptability. Specificity is the holy grail of cancer therapy because it widens the therapeutic window by reducing off-target toxicity. Potency permits relatively small numbers of cells to mediate curative responses. Memory minimizes the potential for recurrence. And adaptability counters the genetic instability of many tumors; tumor cells that express altered proteins (neoantigens) arising from ongoing mutations can be recognized as foreign and eliminated immunologically. Before we can discuss how malignant tumors evade immune surveillance, though, we must consider how tumors arise in the first place.
The Odds Are Not in Our Favor
Let’s do the math. For one cell to become two, it must copy all of its contents. These include proteins, lipids, carbohydrates, and nucleic acids. Nucleic acids are DNA and RNA and are the genetic storage, retrieval, and information transfer systems of the cell. All of the information encoded by a cell’s DNA is called its genome. The genome is akin to a cookbook filled with recipes cells follow to function properly. There are only four different letters in a cell’s cookbook, but each cookbook contains 12.8 billion total letters (6.4 billion base pairs per human diploid genome × 2 nucleotides/base pair). It is estimated that the average human adult has about 37 trillion cells (12). If we assume a daily turnover rate of about 0.5% (200 billion cells), then about 2.5 trillion billion (1021) nucleotides must be copied every day. To put this differently, the DNA in a single human cell is about 2.2 m long (340 pm/base pair × 6.4 billion base pairs/human diploid genome). The length of DNA copied every day is therefore approximately 440 billion meters, which is almost three times the distance from the earth to the sun. Copying errors are inevitable with such large numbers, and these copying errors can alter the recipes in the cookbooks and lead to cancer.
What is Cancer and How Do We Get It
Cancer is defined as a population of cells that grow uncontrollably and invade local or distant tissues. Cancer arises from changes in DNA itself (genetic) or changes in how and when different regions of DNA are accessed (epigenetic). To carry the cookbook analogy further, the addition of the letter “b” to “tsp” increases the amount of an ingredient added from a teaspoon (tsp) to a tablespoon (tbsp). Single letter changes (i.e., point mutations) could have no, slight, or profound consequences, depending on the ingredient and recipe. Changes on a larger scale would be like tearing off the bottom half of one recipe and replacing it with the bottom half of a recipe from a different chapter (i.e., a translocation). Alternatively, the cell might inappropriately use one recipe (e.g., for crème brûlée) when it should have used another (e.g., sautéed liver and onions). This is called an epigenetic error (“epi” means above). The genetic material itself has not changed but the way it is used has. Epigenetic changes could have deleterious consequences for the host (e.g., if guests were promised crème brûlée for dessert but instead were given sautéed liver and onions).
Cellular mechanisms have evolved to minimize genetic mistakes, to correct mistakes once they are made, to provide redundancies to counterbalance loss-of-function mutations, to induce cell death if a cell acquires too many genetic lesions to copy its DNA successfully, and to eliminate nascent malignant cells via immune surveillance. Cancers ultimately evade all of these barriers typically by accumulating mutations and genetic lesions sequentially over decades (11, 13).
With this information we can now distill how someone gets cancer down to three ways. (1) Old age. Cancer is like a biological clock. The longer an individual is alive, the more s/he can acquire deleterious mutations from DNA copying errors or exposure to carcinogens (DNA-damaging agents) that can lead to cancer. (2) Bad luck. An individual can inherit mutated genes that predispose them to cancer, or they can be unintentionally exposed to sufficient doses of carcinogens to cause cancer. (3) Lifestyle choices. Cancer prevention and regular screening are likely the best ways to reduce one’s risk for cancer. Prevention includes minimizing exposure to known carcinogens, being vaccinated against pathogens known to cause cancer, and eating foods rich in anti-oxidants and other known chemopreventive agents. Regular screening (e.g., colonoscopies) can detect cancer at earlier, more treatable stages. It is worth stressing that among old age, bad luck, and lifestyle choice, the only one we can control is our choice of lifestyles.
Cancer Immunotherapy
Cancers co-opt normal biological processes to escape immune surveillance. We present these processes collectively as a wall between the malignant tumor and anti-tumor immune cells (Figure 1A). It has only been in the past 10–20 years that immunologists have begun to understand how cancers erect these walls: what the bricks and mortar are. Although this knowledge has led to many immune-based approaches for cancer therapy, most rely on one of two strategies.
The spheres represent cells of the acquired immune system, with each color representing a different specificity. The brick walls represent tumor-induced immune suppression. The black, 10 point stars represent tumor cells. (A) Escape from immune surveillance. Malignant cells suppress immune effector cells. (B) Checkpoint blockade therapy. Inhibiting cancer-induced immune suppression via checkpoint inhibition permits tumor infiltrating lymphocytes to kill malignant cells. (C) CAR T-cell therapy. Autologous white blood cells (typically T- or NK-cells) are transduced with a CAR-encoding construct, rendering all the transduced cells specific for the same antigen. These cells are expanded to large numbers ex vivo and then infused into the patient.
The first is figuratively to reduce the height of the wall or compromise its integrity (Figure 1B). This permits tumor-infiltrating lymphocytes and other in situ immune effector cells to avoid suppression and eliminate malignant cells. Immunological approaches that fall into this class include checkpoint inhibitors. Checkpoints such as CTLA-4 and PD-1 suppress activated immune cells and allow them to return to homeostasis (14, 15). Some cancers engage these checkpoints and escape immune surveillance; monoclonal antibody-mediated inhibition of checkpoint signaling permits immune-mediated tumor cell death (16, 17). FDA-approved checkpoint inhibitors such as Yervoy (ipilimumab; anti-CTLA-4) and Keytruda (pembrolizumab; anti-PD-1) can profoundly increase survival for some patients with cancers such as melanoma and metastatic non-small cell lung cancer (18).
The second strategy is to induce such a strong immune response that it figuratively crashes over the wall, much like a tsunami breaching a seawall (Figure 1C). This approach relies on mass action: the number of immune effectors exceeds the number of immune inhibitors. This immune tsunami is typically created in three ways. The first is to use a therapeutic vaccine to elicit an anti-tumor response in the patient (19). This approach has had limited success primarily because the patient’s immune system is systemically suppressed by disease and prior therapies. Figuratively this creates a hole in front of the wall making the barrier that much higher.
Discussions of cancer vaccines with lay audiences must address persistent misconceptions about the safety of vaccines. We suggest a multi-pronged approach. State that vaccines are among the biggest success stories in modern medicine. Show pictures of individuals infected with smallpox and pediatric polio victims in iron lungs; these images are likely to have the greatest impact. Show data regarding the dramatic declines in mortality due to vaccination and the eradication of smallpox in 1980 (20). Briefly describe how vaccines elicit pathogen-specific immune responses in the absence of disease; these responses then prevent disease by quickly eliminating the pathogen should it infect again. Note the 1998 publication that fueled the anti-vax movement has been discredited and retracted (21). This paper claimed that the measles/mumps/rubella vaccine was linked to autism in children. However, the data were irreproducible, and the lead author did not reveal that some of his research was funded by lawyers suing vaccine manufacturers. Acknowledge that while vaccinations often cause common local reactions (e.g., pain, swelling, and redness at the injection site), these are minor and transient and simply indicate recruitment of immune cells that subsequently will protect against infection from the pathogen targeted by the vaccine. Conclude that vaccines are a boon to humanity and that herd immunity protects children and immune-compromised individuals.
The second approach to create an efficacious anti-tumor response is to remove tumor-specific cells from the patient, grow them to large numbers in the laboratory, outside of the immune-suppressive environment of the patient’s body, and then return them to the patient. This has had more success than the vaccine approach, but it is hampered by the difficulty in identifying truly tumor-specific immune cells in the patient (22). The third approach takes some of the patient’s healthy white blood cells and genetically reprograms them to recognize and kill tumor cells, regardless of what the immune cells were born to recognize. The engineered autologous cells are expanded ex vivo and then infused in the patient. This approach has been a game changer for certain B-cell leukemias and lymphomas as patients with otherwise incurable diseases are alive today (23). These genetically modified cells are called CAR cells, where the acronym CAR stands for chimeric antigen receptor.
While cancer immunotherapy has enormous potential, we need to caution that providing false hope can be an unintended consequence of presentations like those we just described. The presenter has a moral and ethical obligation to note that many patients still do not respond favorably to cancer immunotherapy, and that it has other drawbacks. These include acute and chronic immune-related adverse effects, cost, and access. More research is needed to overcome these limitations.
Conclusions
In many cultures, storytelling is the traditional method of teaching. In the Hmong culture, skills, customs, historical knowledge, and traditions are passed orally from generation to generation via rote learning, memorizing, and storytelling (24). Because humans are attuned to story-telling, we tell stories based on immunology and cancer immunotherapy that weave in facts with easily recognizable analogies. We typically begin talks on cancer immunotherapy with a picture taken in 2010 of five-year old Emily Whitehead, the first pediatric patient treated with CD19-specific CAR T-cells (23). The Whitehead family has allowed Emily’s story to be told publicly to promote immunotherapy. We say that in 1960, Emily would have had a 10% chance of survival given her diagnosis of pre-B-cell acute lymphoblastic leukemia. But thanks to 50 years of research, her prognosis in 2010 was much better as her chances of long-term survival were 85–90%. Unfortunately, she relapsed following standard therapy and was near death with resistant disease in 2012. We then state we will return to Emily at the end of the talk, which we do after presenting the above material starting with immune activation and ending with cancer immunotherapy. At the end of our presentation we close the story loop by showing a picture of a healthy teenage Emily taken in 2019. At this point we present the limitations of immunotherapy, particularly CAR T-cell immunotherapy, and note that only more research will lead to improved outcomes with reduced off-tumor effects. We then have an open question and answer period followed by informal interactions with the attendees.
We routinely provide our slide decks to the attendees electronically and give them printed materials with contact information for MCC specifically and cancer immunotherapy in general. We have pamphlets printed in English, Hmong, Somali, and Spanish to reflect the demographics of our community. These outreach efforts are almost always well-received and leave attendees with the belief that their time was well spent.
Author Contributions
KE and CP developed various community outreach activities related to cancer prevention and immunotherapy, and together outlined and wrote this article.
Conflict of Interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Acknowledgments
We thank the other members of MCC’s Office of Community Engagement and Education: Patricia Beckmann, Sylvette Lopez-Ruth, and Lisandrea Martinez.
Footnotes
Funding. We gratefully acknowledge the philanthropic support of the Minnesota Masonic Charities and MCC’s Cancer Center Support Grant from the NCI (P30-CA077598-21).
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Theme Music and Special Thanks
SPECIAL THANKS:
Wendy Gahagan, Animal Episode Portraits
Vinnie Rodriguez, Logo Design
Lori Pryt, Cartoon of Dr. Kent