Influenza Virus Jumps to Dogs A flu virus jumps species -- from horses to dogs. The virus has killed racing greyhounds, but what does it mean for pet dogs?

Influenza Virus Jumps to Dogs

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You're listening to TALK OF THE NATION/SCIENCE FRIDAY. I am Ira Flatow.

Up next, something you may have heard about already, especially if you're a dog owner. It's the canine flu virus that's spreading across the country. It was first discovered at a greyhound racing track in Jacksonville, Florida, and the flu has spread to tracks in several other states as well as kennels and vet clinics, and this flu can be fatal. And because it's an emerging disease in dogs, they don't have a natural immunity to it, so nearly every dog exposed to the virus will get it. Could your dog be at risk?

Well, here with some of the answers is one of the scientists who first discovered this disease in the Florida greyhound population. Cynda Crawford is an immunologist in the department of small animal clinical studies at the University of Florida College of Veterinary Medicine in Gainesville. She joins us from the campus there.

Welcome to the program, Dr. Crawford.

Dr. CYNDA CRAWFORD (University of Florida College of Veterinary Medicine): Thank you, Ira. Glad to be here.

FLATOW: You're welcome. Tell us a little about the history. This story begins last year when some racing greyhounds got sick?

Dr. CRAWFORD: That is correct. It started actually back in late 2003 when we put together a research team here at the University of Florida to determine what causes outbreaks of respiratory disease in racing greyhounds. And that's the number-one health problem with that dog population. And our first initial outbreak for investigations just happened to occur in January of 2004 and we stumbled upon the virus during that outbreak, and it's all been a roller coaster since.

FLATOW: And what was also interesting about it is you discovered that it was very similar to a horse virus.

Dr. CRAWFORD: Yes, it is. This virus has evolved from the equine influenza virus. There have been some changes in the structure of the virus that is now infecting the dog, though.

FLATOW: So it jumped from horses to dogs, you think?

Dr. CRAWFORD: Yes, it did; it did jump from horses to dogs. We don't know when. We think it's in the recent past. We don't know if it was really in the Jacksonville area. It could've been somewhere else in North America or even on another continent.

FLATOW: And how far has this virus spread now in the dog population?

Dr. CRAWFORD: It has spread to three or four states so far in this country, as verified by testing of samples submitted from dogs that have a clinical syndrome that fits the flu profile.

FLATOW: And is it spreading from dog to dog now?

Dr. CRAWFORD: Yes, it is. That's one of the unique properties of this whole event, is that once the horse virus started infecting dogs, it actually adapted to the dogs so that the dog could now serve as a source of infection to other dogs.

FLATOW: And I understand that it has shown up in dogs as far away and as apart as New York and California.

Dr. CRAWFORD: Yes, it has.

FLATOW: Wow. Does that worry you?

Dr. CRAWFORD: Well, it doesn't worry me. It's something that I suspected would happen and really (technical difficulties) be in dogs in virtually every state. Once we complete the testing with all the, you know, cooperation of the dog owners and veterinarians, I think we'll have a pretty full map of the United States.

FLATOW: So it's not just the racing hounds, dogs anymore; it's in dogs that are, you know, at your vet?

Dr. CRAWFORD: That is correct.

FLATOW: And how dangerous is it if your dog gets, you know, infected?

Dr. CRAWFORD: It's not dangerous to the vast majority of dogs, just like flu infection of people is not dangerous to the large majority of people. Most dogs that do get infected and have a clinical disease will recover without any complications. It's only a few dogs that can actually progress to pneumonia. And if those dogs are treated very appropriately under the supervision of a veterinarian, most of those dogs will survive also.

FLATOW: Talking with Cynda Crawford, a veterinarian at the University of Florida College of Veterinary Medicine in Gainesville. Our number: 1 (800) 989-8255.

Let's go to the phones, 'cause you know everybody loves dogs. Harold in Jacksonville. Hi, Harold.

HAROLD (Caller): Hey there, how you doing?

FLATOW: Hi, how are you?

HAROLD: Good. My question is two parts. You know, I have a dog and I take him for a walk. And this probably sounds extreme, but you know dogs like to check out the markings left behind by other dogs, so is there any need for concern there? And also, has there been any cases of where this may be showing signs of jumping from dogs to cats? And I can take my answer from the radio.

FLATOW: All right, Harold. Thanks.


Dr. CRAWFORD: Thank you, Harold. Those are two very good questions. Dogs that are just out on a walk around their neighborhood and doing their usual doggie business and sniffing around aren't in a high-risk group for exposure to the canine influenza virus. As a matter of fact, I think that's a low-risk activity.

With regard to infection of cats, I can sign you up to be on our team because we thought about that a few months ago. As you know or probably heard, respiratory infections are the number-one problem with cats, particularly those cats in shelters. We have done some testing on a very limited number of cats in the shelter facilities and have not found any evidence of influenza virus infection in them.

FLATOW: So in terms of walking your dog not being a high-risk activity, is dogs being next to each other or touching other dogs, is that where it's spread?

Dr. CRAWFORD: It's very similar to how an infectious disease spreads in people, particularly in school-age children when they're at school in classrooms with 30 to 50 other students. The common theme is to have a lot of people or a lot of dogs all together in close quarters under one roof.

FLATOW: Are there any symptoms you should watch for in your dog?

Dr. CRAWFORD: Yes, there are. The flu virus is just one of many bacteria or other viral agents that can cause a respiratory disease, generally referred to as kennel cough. And nearly every dog owner recognizes the term `kennel cough.' The influenza virus--the most common sign is a cough. This can persist from one to four weeks. Some dogs may even have a cough that nags on for six weeks. Some of those dogs do develop a runny nose, and then others will develop the pneumonia syndrome, which is characterized by a high fever, sometimes as high as 105 degrees Fahrenheit. The dog is very tired, lethargic, won't eat and has rapid, shallow, labored breathing.

FLATOW: And that--get your dog to the vet.

Dr. CRAWFORD: Absolutely.

FLATOW: Yeah. Yeah, of course, if you have a healthy dog, the vet might be a place where he or she picks up the virus.

Dr. CRAWFORD: That's true, and that's one of the points I think that's very good with all of you all participating in getting the word out to dog owners and veterinarians this week. The more we can educate the veterinary medical community and dog owners, the more precautions that veterinary facilities will take when they have a dog coming in with a respiratory infection. And they can isolate that dog so that that dog is not a source of infection to other dogs at the clinic that day.

FLATOW: Is word getting out to the vets now, do you think?

Dr. CRAWFORD: Yes. It is getting out the veterinarians if I can kind of gauge based on the number of phone calls I get a day and e-mails, but it still needs to be an ongoing process on our part to be sure that we keep supplying veterinarians with the most up-to-date information.

FLATOW: Hi, Sandra in North Carolina. Hi. Welcome.

SANDRA (Caller): Hi, good morning. Or good afternoon, I should say, Ira. I have a pug. He's a house pet at my house. And he's like my little boy, my son. And I...

FLATOW: We understand.

SANDRA: And I just want to ensure, one, when I take him to the vet, is there anything that I could do to possibly keep him away from any of the carriers or wipe down the table? And two, what are the symptoms of this?

Dr. CRAWFORD: OK, good question. Number one, veterinarians, I think, with their heightened awareness of the existence of the canine influenza virus in the dog community now and by virtue of its contagious nature are taking lots of precautions over and above what they normally do. They always clean an exam room in between dogs and the staff usually wash their hands. I think what's going to happen now is that if the receptionist at the vet clinic gets a call from a client and says my dog has a cough, I think what will happen at that clinic to ensure that your pug doesn't get sick half an hour later when you come in is that sick dog will be handled in a manner where it will it not come in contact with common areas that other dogs will be at.

FLATOW: Let me ask you this question. If your neighbor has a dog that's sick and your kids play with that dog, can you transfer the virus by hand to your dog?

Dr. CRAWFORD: There have been instances where kennel workers working with dogs who do have flu infection have actually taken something home anyway so that their own pet dogs became sick with the flu. And this was all confirmed by testing and not just supposition. So we have (technical difficulties) people can be a source of infection from dog to dog if they handle a sick dog and then do not follow proper hygiene measures before they handle a dog that is not sick.

FLATOW: So wash your hands, maybe use some of those alcohol-based sanitizers, things like that?


FLATOW: Yeah. What about, you know--when we hear about the flu, we normally think of vaccine. Any possibility of a vaccine for dogs on this one?

Dr. CRAWFORD: Yes, we do need a vaccine for this. And we have someone that's been working on the vaccine now for probably close to six months. Unfortunately, it takes two to three years to show or demonstrate the efficacy of the vaccine in preventing the disease that it's designed to prevent as well as that it's a safe product to administer to the dog. So there's some regulatory hurdles that every new biologic product, including vaccines for dogs and cats and other companion animals, must pass before it can be sold to the public.

FLATOW: Can people--they're going to want to know. Can people catch the flu from their dog if it's infected?

Dr. CRAWFORD: That's another very good (technical difficulties)...

FLATOW: Whoop.

Dr. CRAWFORD: ...(technical difficulties) everybody's thinking about (technical difficulties) flu and (technical difficulties) bird flu is infecting people. The equine influenza virus has been in horses for 40 years in this country and there's not been any documented reports of people catching a flulike illness from being around horses with influenza. Now the canine virus is very closely related to the equine influenza virus, so we can make some extrapolation there. In addition, the canine virus and the equine virus are not very closely related to human influenza viruses or avian influenza viruses at all. But in medicine and science, you never say no.


Dr. CRAWFORD: You never say never because that will jinx you. We think the possibility of humans acquiring infections from dogs that have influenza virus infection is remote. But the CDC has set a plan in motion here to track or do surveillance work on people who report to their physician that they have a flulike illness that they think they got from their dog.


Talking with Cynda Crawford, DVM, immunologist of the department of small animal clinic sciences at the University of Florida College of Veterinary Medicine on TALK OF THE NATION/SCIENCE FRIDAY from NPR News. I'm Ira Flatow.

Did this virus spread quickly? Did it really--I mean, it's gone so far. You know? Or was it sort of a normal method, do you think?

Dr. CRAWFORD: No, I think you're probably right on the latter comment in that it may not be the fact that the virus is spreading quickly; it may be actually a function of the fact that we're looking for it now.


Dr. CRAWFORD: And so it may have been there for a long time and (technical difficulties) because we have not learned in veterinary school that (technical difficulties) virus is a pathogen for dogs.

FLATOW: Does it--and so let's repeat a little bit. I know we've talked a bit about this. It doesn't mean that just because your dog gets the virus that it's going to die from it.

Dr. CRAWFORD: Absolutely. It does not mean that at all. Most dogs recover from influenza virus infection just fine. It may be a little bit longer than what people are used to for dogs with so-called kennel cough, but they will recover.

FLATOW: And a symptom of it would be, as you say, something like a kennel cough.

Dr. CRAWFORD: Something like a kennel cough. Again, it's something--a common term that dog owners relate to very well. And it is just a syndrome characterized by coughing.

FLATOW: And a fever?

Dr. CRAWFORD: Yes. Fever can occur with kennel cough due to other infectious agents besides influenza. I think that fever occurs more often with an influenza virus infection.

FLATOW: And this being the winter season upon us, would we expect it to spread more now? We see flus in the wintertime.

Dr. CRAWFORD: We haven't noticed a seasonality with the canine influenza virus infections. It seems to occur year-round.

FLATOW: And this has been around now for over a year then?

Dr. CRAWFORD: Since January 2004, but we have some preliminary evidence that the virus has actually been around since 2003. It may be even earlier.

FLATOW: So it might have just been missed as some other kind of illness?

Dr. CRAWFORD: Yes, Ira, I think that's a pretty fair statement right there. So we have some studies where we're trying to do some backtracking to see when is the earliest date or year that we can pick up evidence that...

FLATOW: Yeah. Yeah.

Dr. CRAWFORD: ...this virus was there.

FLATOW: And in the meantime you'll be watching out for possibly crossing over into other pets in the family, like cats?

Dr. CRAWFORD: Yes. And I'm very interested in keeping tabs on the ability of this virus to infect cats because cats are not that different from dogs.

FLATOW: Should people watch out for that in their cats now?

Dr. CRAWFORD: Well, I think people should be cognizant of any respiratory signs that their cat is exhibiting and call their veterinarian.

FLATOW: Yeah. OK. Those are good words, and I'm hoping that we've soothed some of the fears of, you know, pet owners, at least tell them to, you know, take their dogs or maybe their cats to their vets and not to lose hope if they do start getting a cough or maybe have this virus.

Dr. CRAWFORD: I agree. I think things in most cases will work out just fine.

FLATOW: Well, Dr. Crawford, thank you for taking time to talk with us.

Dr. CRAWFORD: I have enjoyed it, Ira. And please thank your callers. I enjoyed their questions.

FLATOW: They are pretty smart. Thank you.

Cynda Crawford, DVM, is an immunologist in the department of small animal clinical sciences at the University of Florida College of Veterinary Medicine. That's in Gainesville.


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I'm Ira Flatow in New York.

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