Blood Diseases in Animals

Featuring Helen Osborne and John W. Harvey

John W. Harvey received his DVM degree from Kansas State University, followed by a PhD degree in Physiology from the University of California, Davis. He then served on the faculty at the University of Florida College of Veterinary Medicine for 40 years. He is board certified as a clinical pathologist by the American College of Veterinary Pathologists. His research has involved various aspects of veterinary hematology. Notable first-time discoveries include an infectious disease of dog platelets named Anaplasma platys and inherited methemoglobin reductase, phosphofructokinase, and flavin adenine dinucleotide erythrocyte deficiencies. His most recent book is Veterinary Hematology: A Diagnostic Guide and Color Atlas..

John Harvey, DVM, PhD, Emeritus Professor

In this podcast, Dr. John Harvey talks with Helen Osborne about:

  • Diseases. Examples of blood diseases in animals that are similar or different from those in humans. How blood diseases in animals are not necessarily the same across species. Plus more. 
  • Diagnostics. Getting blood samples from animals. Diagnostics for disease and routine screening tests as animals age. The science of what you see and learn in the lab. 
  • Research. Challenge to get funding if not about human disease. Other ways to keep learning about blood diseases in animals. 

Music by Skilsel from Pixabay.

Producer and audio editor: Kip Clark


HELEN: Welcome to Talking about Blood. I’m Helen Osborne, host of this podcast series and a member of the Advisory Board for The Blood Project. I also produce and host my own podcast series about many aspects of health communication and it’s called Health Literacy Out Loud. The Blood Project’s website includes a lot of important science information including what happens at the clinic and in the lab. This can extend beyond human medicine to also look at blood in animals. I’m delighted to be talking today with an expert on this subject, Dr. John Harvey. He is a board-certified clinical Veterinary pathologist and now is Professor Emeritus of University of Florida’s College of Veterinary Medicine. John is widely recognized for his expertise and research in comparative hematology, including his discovery of an infectious disease of dog platelets. John is a prolific author and speaker, and has been honored numerous times for his great work. John is also a member of The Blood Project’s Advisory Board. Welcome to Talking about Blood.

JOHN: Well, it’s great to be with you, Helen.

HELEN: Can you just give all of us an overview about blood diseases in animals and how these are similar or different from blood diseases in humans.

JOHN: Well, I would say there’s a lot more similarities than differences. So we have a lot of common disorders from the leukemias to the iron deficiencies and so forth. But there are unique individual animal differences.

HELEN: Give us some examples. You know this world so well. I just think of dogs and cats that I know and love, but give some examples please.

JOHN: Well, I mentioned one to start. We could look at iron deficiency anemia, which is, in animals, quite common for those species that have blood loss parasites. So, this is usually chronic bleeding. Dietary iron deficiency is extremely rare and animals, except for nursing animals, because milk is low in iron. So that’s one that’s quite common in certain species that more likely have bleeding. Then we have examples of things that don’t happen. For example, we don’t have some of the hereditary problems of humans like the thalassemias, but we do have some hereditary enzyme deficiencies such as pyruvate kinase deficiency or phosphofructokinase deficiency or other things, so we have some similarities and some differences.

HELEN: There’s a wide kingdom of animals in this world. Do all animals, have blood diseases in the same ways?

JOHN: No, they vary quite a bit as to what is important in one species versus another. We have to learn a lot about each of the different animal species. One of the difficulties of course is evaluating their blood. It’s a real issue for the non-mammals. So, mammals have red cells that have no nuclei and platelets – that are for hemostasis or stopping bleeding – have no nuclei, but everything is nucleated in non-mammals. So, they’re what we call thrombocytes that stop bleeding, the leukocytes and erythrocytes are all nucleated. So, those are hard to evaluate with our machines.

HELEN: Give us a clue about you. You and I had the treat of talking a little bit ahead of time of this podcast. You’re talking all about that science of what happens in the blood. Your focus of the work as a veterinary hematologist. Put that into context for us. What does someone with that background do?

JOHN: Well, a lot of our focus is on diagnosis of disease and when you look at blood, you find that some of the abnormalities you see in blood are actually diseases of blood. But a lot of what we evaluate in blood is looking for disease elsewhere in the body, both hematology – that’s the cells of the blood – but the plasma that we evaluate called biochemistry for everything from measuring glucose to sodium and chloride and so on. And so much of what we evaluate actually shows us evidence of disease elsewhere in the body but sometimes the disease occurs in the blood itself.

HELEN: We’ve done another podcast and we’ll have a link to that later about what happens in the lab looking at blood and I’m sure that was about human medicine but it talked about how blood, you know, is kind of the entry point to learn all about that’s going on about the whole body. It sounds like that’s certainly an issue that’s very common in the work you do as well as human medicine. I got another question there. I’m thinking of a cute little puppy I know, or a little kitty cat who hates to go to the vet. How in the world does an animal give that blood? And is it the same as just saying to me, as a grown up, just go to the lab and give some blood. What’s that like from the origin on?

JOHN: To collect the blood sample? It’s been equated veterinary hematology sort of like pediatric hematology, you know, the children are not exactly helpful sometimes in allowing blood to be collected. Some ways it’s sort of like bleeding a kitten. It’s not that much different than trying to bleed a small child size wise, as well as non-cooperation, shall we say.

HELEN: All right, but with the child, you can promise the lollipop later. That doesn’t work for that little kitten.

JOHN: Right, it doesn’t. And then we use the different veins for different species, so it really depends on the ability to restrain them and then where we can get a good blood sample.

HLELEN: Thank you. You’re making that much more vivid. So, once you get that blood and it goes to the lab, I think that’s where you and your colleagues come in. Is looking at the blood the same process? So is it just looking at the science and the cellular structure and the pathology, or is there something unique about animals’ blood?

JOHN: In general, it’s the same. We’ll talk first just about mammals because the mammal blood we can run through the same hematology analyzers that are used for humans. They have to be modified to be able to count cells accurately. The red cells vary in size, for example, platelets vary in size, and then, especially to try to do an automated white cell differential – that’s the other blood cell type – each of these cells look different or some of them at least look different, depending on the species. Even dog and cat cells don’t look identical. And so the machine has to be calibrated to be able to pick up those differences.

HELEN: And what kind of a lab does that. Is that a special lab for animals?

JOHN: It is primarily now. So, I’m at a university hospital. And so we have our equipment but there’s several major laboratories around the US as well as around the world where veterinarians can submit their samples for blood. But, there’s also now small instruments that veterinary practices can run their own blood samples through and there’s different settings for each of the species. And so this is very important. You can’t just run the blood through the machine that’s set up for human samples. It has to be modified software – not the machine itself, but the software has to be modified.

HELEN: That’s really interesting and because you have this vast number of species as opposed to the human is the human. So we have to modify it. Is this a specialty area of training as people go through learning how to be a veterinarian, is the pathology of this?

JOHN: Yes. Well, we have a course – in fact, I’m teaching veterinary hematology right now to our students, teaching them how to evaluate the results they are going to be getting from the laboratory, and then people like me that are interested in more depth can do a residency and then a board certification – in our case, Clinical Pathology. So it’s all the laboratory parts, not just hematology. It includes clinical chemistry, urinalysis and so forth as well.

HELEN: Well those parts, you know, the average pet owner wouldn’t be seeing. What about the issue of routine blood screening? Certainly, that’s something I’m familiar with. Given how cumbersome and difficult it can be to take a sample from an animal – an uncooperative or you know, an animal that doesn’t want that. Do you do the routine screens, so you have a form of comparison later on?

JOHN: Yes, we do. It’s become much more common now to have yearly exams. Often animals need to be brought in for vaccinations anyway. Or one of the problems is not related to blood and that’s teeth cleaning. Animals have to have their teeth cleaned. Well, they have to be anesthetized. They’re not going to tolerate that and so then you can take a blood sample at the same time and see just like I do each year to see – I get a baseline lab data. Sometimes we pick up unknown problems. We might pick up diabetes with high glucose, for example, that might not be known until a blood sample is collected for dentistry.

HELEN: Thanks. It makes it very vivid to me. So, the role of research and learning more about this, you’ve written so many papers, your known worldwide for your work. Is there a lot of new learning happening when it comes to veterinary hematology?

JOHN: Yes and no. Certainly there’s new knowledge out there all the time. We have some research that’s done just specifically for dogs or cats or horses. Unfortunately, we don’t have the same money support that happens for human health. So, if we have a disease in a dog or a cat or a horse that’s similar, or the same as a human disease, then we may be able to get money for that. For example, I had an NIH Grant to study a problem in dog blood that occurs in humans. But if you don’t have that opportunity, then the amount of money available is much smaller. So, we depend a lot on research from humans and rodents, of course, are one of the big sources of basic research.

HELEN: And then, so it’s part of your learning and your teaching is how to make sense of that data that you’re getting from other species and have it applied to animals. Correct?

JOHN: That true. And I think it’s important to recognize that there’s a lot of commonalities, but there are differences. And there’s of course, all kinds of things that have been discovered in humans where they did the research say in rodents and then tried to apply that to humans and it didn’t work well. And so sometimes thing translate across species and sometimes they don’t. So, we have to be very cautious when we look at results from one species and then try to extrapolate to another

HELEN: This is fascinating. All right, John our listeners. You’re part of The Blood Project like I am. But you know that our listeners include seasoned hematologists, people who have been doing this work generally in human medicine but hopefully that ___ too at this point. People have been doing this work a while. Our listeners, hopefully, are also including those newer entering the healthcare fields, newer to the sciences and those people just like me. I feel like I represent that audience in ways who are just curious about blood and all the ways it affects beings. What advice or tips would you have for each of these groups? And I guess let’s start with the seasoned professionals. What would you want them to know that perhaps they don’t already about animals and blood?

JOHN: One of the main things for the professionals is to recognize the depth and breadth of what we know about animal blood and the similarities that occur because there’s a tendency ___ that humans are unique. And it’s important to recognize what part of the animal kingdom here. So everything has some uniqueness, all species are somewhat unique, but we’re not that different than we think. And our genome is not that different when you look at the percent of differences in genes across species. So I think that’s one of the things is just to recognize that some of the same things occur. And in some cases we know a lot about these other diseases and in some cases they need to get be discovered.

HELEN: We all can be learning from each other. What about those who are newer in their careers, or even just considering going into the sciences.

JOHN: You know, for me, part of it, the interest in science is just the joy of learning new things. How does this happen? How does this work? And I think somebody might want to know how a machine works. In my case, I wanted to understand how the physiology of the body works and particularly blood that interacts with all these different body parts, how that is all related. And so to me some of it’s just the fun of discovery. A comfort level to know a little more about what’s going on in, not only an animal’s body, but your own body.

HELEN: You use the word “joy” in there. I have to just tell you and listeners. I have such a joy doing these podcasts and listening to folks like you who are just broadening my whole understanding of science and medicine and why people are doing what they do. So thank you for that. I can relate to that one quite a bit – about that joy. And for those entering the fields and deciding what they wanted to do in this world, joy is a part of what you’re committing to for the next decades and decades of your life. What about those who are just simply curious. What overarching factor would you want us to know about blood and animals?

JOHN: Wow, that’s a hard question because it’s been so long ago that I started thinking about why I was interested in. As a child, I started with this interest in animals and how the body worked back in grade school I guess and eventually decided veterinary medicine was the direction for me to take. You’ve sort of addressed, it is curiosity. And I read recently where someone said, curiosity is actually often the first step to joy. We start thinking of these things and the more we learn the more excited we can be. My feeling is that you find something in life that really excites you. And if you’re lucky enough like me to make a job as well as something you enjoy that, that’s fantastic. But it just looks so important. And so for those listeners that said there’s something about living organisms that excites me I think then you want to go deeper in whatever direction – whether it’s animals or humans or plants or whatever that is life-giving.  

HELEN: thank you. Oh I can relate to all of that. It keeps us going for all these decades.

JOHN: One quote that I’ve liked is that there was a man he’s dead now called Joseph Campbell and he wrote a book called The Power of Myth and his whole message was follow your bliss. Follow your bliss. Find something that excites you, and follow that.

HELEN: Thank you. And that’s actually what The Blood Project is all about. It’s really about the bliss and the discovery and the joy, and the excitement about learning about blood and all the aspects, including the humanity of it, in addition to the science. John, thank you so much for being a guest on Talking about Blood and sharing with us all these stories and examples and giving us a window into the world of blood and animals.

JOHN:  Was happy to do it enjoyed talking to you, Helen.

HELEN: As we just heard from veterinarian John Harvey, it’s important to consider blood in all species, not just the human species but also animals. To help learn more about The Blood Project and explore its many resources for professionals, trainees and patients, go to thebloodproject.com. I also invite you to listen to my other podcast series about health communication. It’s at healthliteracyoutloud.com. Please help spread the word about this podcast series and The Blood Project. Thank you for listening. Until next time, I’m Helen Osborne.