Canine Influenza

From the monthly column "Thoughts I Had Driving Home From The Dog Show". ShowSight, August 2017 Issue.

"My dog is at the University of Florida vet school…he's very sick." 

"My dog is sick too...."

As more dogs fell ill with severe coughing and fever it became clear this wasn't just another bout of kennel cough or of people griping about some new dog show crud. We had the beginnings of a flu epidemic.

Most of the affected dogs had in common that they or a housemate had attended either the May shows in Perry, Georgia or the shows in Deland, Florida the following week.

Edy Dykstra-Blum was among the first to post daily Facebook reports of her Old English Sheepdog, Traynor's, battle that eventually landed him in isolation at the University of Florida Veterinary School. Three days after the Perry shows Traynor started coughing. "At first I thought it was kennel cough, but the incubation time was too short, and his temperature was 103.7."  Her veterinarian put him on antibiotics. "Two days later I woke up to a sound of strange crackling breathing, like he was drowning.  We took him to the ER vet at 2 in the morning, they took him through the back door and an x-ray confirmed pneumonia… By that time all my other dogs were coughing…" Traynor and all her dogs at home tested positive for H3N2. Traynor was admitted to the UF Hospital.

"The isolation ward at UF was overfull in a few days," Edy recalls. "I was glad I could visit just one day dressed in full protective gear.  Four days later, I could get my boy back and we were not even allowed to go near the entrance of the isolation ward, this is how serious this flu is."

Karan Aurelius was also at those shows. Her dogs seemed fine until the first one started to cough seven days later. She, too, initially assumed kennel cough because the dog's temperature was normal.  But her other dogs, even those that weren't at the show, started to get sick as well. She had a litter of two-week old puppies at home. Their dam woke her up coughing in the middle of the night. Four hours later she was running a temperature of 106. Karan had her at the vet clinic when they opened. "They wanted to admit her but by that time they knew it was something serious and contagious. They would have needed a positive pressure isolation room, with its own air system and pressurized such that doesn't leak air into the rest of the clinic."

More of her dogs started to show signs. Three of her five puppies got sick. "They went down fast," she recalls, "but they all survived." In all, 28 of the 30 dogs in her care eventually came down with the flu. It got worse. "Our house dogs' yard shares a common fence with my roommate's boarding kennel. We called all of our boarders with the news of what we still at that time thought was kennel cough. A Belgian Malinois that had already gone home got sick the next day—he died in the veterinarian's parking lot." The necropsy revealed canine flu H3N2. 

Karan, a former vet tech, spent two weeks nursing her dogs around the clock. "We kept charts on everyone—temperatures, appetite, medications. Everyone went on doxycycline, some on clavamox, some on even more medications. One needed a bronchodilator. There were sub-Q fluids to help keep temperatures down, nebulizers, some with essential oils. We were exhausted."

She wasn't the only one.  Rindi Gaudet was yet another of many professional handlers who not only worked around the clock to nurse sick dogs but also missed over a month of income. Four days after showing in Deland she was in Pennsylvania preparing for shows when one dog, then the other, started to clear its throat. "By then we knew what it probably was, so I packed up everybody and went home." By the time she got home three dogs were coughing. By Monday all 22 of her dogs were coughing. "We had them all tested, but only the ones actively coughing ever came back positive."

Her dogs were sick for over a week, but like Karan and others, her problems weren't over. During the 2015 H3N2 outbreak, one study looked at the duration of shedding of active virus in order to guide isolation protocols for infected dogs. Dogs were shown to shed the virus for 20 to 24 days after infection. According to AKC Rules and regulations Applying to Dog Shows:  CHAPTER 11,  SECTION 9. "No dog shall be eligible to compete at any show, no dog shall be brought into the grounds or premises of any dog show, and any dog which may have been brought into the grounds or premises of a dog show shall immediately be removed if it: (a) shows clinical symptoms of distemper, infectious hepatitis, leptospirosis or other communicable disease, or (b) is known to have been in contact with distemper, infectious hepatitis, leptospirosis or other communicable disease within thirty days prior to the opening of the show, or (c) has been kenneled within thirty days prior to the opening of the show on premises on which there existed distemper, infectious hepatitis, leptospirosis or other communicable disease."

But it wasn't the regulations that kept handlers home. As Karan says: "I just couldn't imagine inflicting this on anyone else or their dogs." That meant giving up handling and in some cases, boarding and grooming, income for over a month. Even that insurance with the duck doesn't cover that, but Gaudet says she is looking into Business Interrupted Insurance for the future. In some cases it meant dealing with clients who didn't understand why their symptom-free dog couldn't go to shows. It meant, for professionals and owner-handlers alike, giving up that show they'd been looking forward to for months, and possibly sliding down in the rankings.

Those with affected dogs begged their Facebook friends to stay home or get vaccinated.  Many heeded the advice to stay home. About a quarter of the entry was absent in North Carolina shows a week later; by two weeks later a Louisiana show had only 191 dogs show up out of 514 entered. The Kennel Club of Texarkana cancelled their 50th anniversary show. Several agility trials also cancelled.  Some questioned why the AKC didn't simply put a moratorium on dog shows, but that would entail forcing handlers, vendors, photographers and others to lose income, as well as causing clubs to lose nonrefundable venue fees and other deposits—and could have in fact triggered lawsuits. And cancelling shows only in the Southeast would have encouraged exhibitors to carry it with the to shows in other areas. As AKC Chief Veterinarian Jerry Klein commented: “It’s tough,” Klein said. “If we close for 30 days—as some have suggested—on day 31 the flu may appear." In the end it comes down to personal choice and responsibility.

Dr. Richard Hawke, a North Carolina veterinarian whose Black Russian Terriers were infected at the Perry show, lost his older dog to the flu. He conducted an informal Facebook survey in early June, and reported approximately 600 dogs owned by 102 people had contracted what appeared to be canine flu, with about half catching it at a dog show and half from dogs that caught it from those dogs. The sick dogs lived in FL (43%), GA 5%, NC 9%, SC 3%, VA 5%, TN 5%, KY 2%, PA 13%, IL 4%, KS 2%, CA 2%, WA 1% and TX 2%. Four dogs had died. However, we now know that many more dogs died. Many of the dogs that succumbed had other underlying conditions so it's suspected that the flu acted in concert with these pre-existing conditions to weaken the dog. Dr. Hawke advised exhibitors to either stay home or get vaccinated, pointing out not only the threat of death, but that his dogs were sick for more than 10 days and that even though he owns a veterinary clinic he spent a "fortune" on drugs to treat them.

Dogs that die from flu die from pneumonia, often hemorrhagic pneumonia. Even if they recover, they may be left with compromised lung function. 

A vaccination against both the older H3N8 strain and the newer (current) H3N2 strain is available. It is given as a two-part series, with the second injection given two to four weeks following the first.  Ronald Schultz, PHD, Professor of Pathobiological Sciences at the University of Wisconsin School of Veterinary Medicine, stated in a release from Merck Animal Health (which offers a bivalent canine influenza vaccine) that “Dogs at risk should be vaccinated at least yearly with both influenza strains, H3N8 and H3N2.”

But many people dragged their feet, based in large part on an article that appear in the generally anti-vaccination Dogs Naturally online magazine that basically claimed the vaccination and flu scare were Merck's scheme to sell vaccination; that they had rushed it to market untested; that it was ineffective; that this flu may have already mutated since it was developed and in fact a study in pigs showed that a vaccine against a related but not exactly the same strain of flu in pigs made the pigs get sicker; and that the only dogs that got really sick were those that were already in poor health.  

It's true that the vaccination doesn't protect totally. But it does make the dogs who get flu less sick and sick for less time.  One of the dogs in the Rindi Gaudet's van had in fact received its first flu vaccination, and while that dog was also affected, he was not sick as long or as seriously as the others.

The allegation that the only dogs that contracted flu were in poor health caused some explosive arguments online.  "Just feed them immuno-boosters and a good diet," some people said. Gaudet feeds her dogs a plethora of vitamins and immuno-boosters on top of a healthy diet; it didn't help her dogs avoid infection.

Many questions remain about the vaccination, so I spoke with Madeleine Stahl, DVM, Associate Director of Scientific Marketing Affairs at Merck Pharmaceutical company.  Here are my questions and her answers:

1) Should a "conditional license" be a cause for concern? MS: The USDA grants conditional licenses for emerging diseases and emergency situations to get vaccine out as quickly as possible. The vaccine must be shown to be safe and have a reasonable expectation of efficacy. In the case of the H3N2 and bivalent vaccines, they've already moved on to full license as they were created by simply substituting the N2 virus for the N8. We had already presented efficacy data at veterinary conferences for the N2 vaccine. Note that when the N8 vaccine first came out it was also under a conditional license, but it's since been given to more than 7 million dogs safely.

(Note: I've seen the Abstracts and Technical Bulletins for these studies. Briefly, H3N2 vaccinated versus placebo vaccinated puppies were exposed to H3N2 virus about a month after vaccination. All dogs were scored using a point scale for depression, coughing, sneezing, dyspnea, nasal discharge, and fever. Dogs that received the vaccination had a mean score of 4.2 compared to the placebo group with a mean score of 20.2. None of the H3N2 vaccinated dogs died, compared to 21% of the placebo vaccinated dogs.)

2) Why not just give one shot rather than two? MS: With any inactivated vaccine you need two doses to get full protection. The first dose will give some protective response, but it mainly primes the immune system to recognize the virus and prepare to fight it. The second dose, given two to four weeks later, ramps up the protection and activates immune memory cell responses.  The vaccine does not really protect until two weeks after the second vaccination.

3) Why two weeks later? MS: The two to four week booster is a general rule for vaccines to allow the immune system to get ramped up.  I would space the shots two weeks apart since in this case we want immunity as quickly as possible. You could probably go six to eight weeks before you'd have to start over.

4) What about the yearly booster? MS: The flu vaccine, like many respiratory vaccines, doesn't seem to last as long as some other vaccines. The annual booster is just one shot.

5) What about puppies? MS: The vaccine can be given to puppies as young as 7 weeks of age.  It should be given at the same time as the other puppy vaccinations. If you cannot do so, wait at least two weeks. Giving a vaccination earlier than two weeks often inhibits the second vaccine.  The vaccine is the same amount in puppies versus adults, small versus large, as the immune system is not dose dependent. 

6) What about breeding dogs? MS:  There are no known contraindications for breeding animals, but as with most vaccines, the flu vaccine has not been specifically tested in them. It's a killed virus so no chance of replication. It's possible that a pregnant or lactating dam could be immunosuppressed so might not mount the optimal response. But the alternative would be to leave her unvaccinated through pregnancy and lactation and then have to wait for the two vaccinations then an additional two weeks–that's about five months of being unprotected! We advise to give it before breeding. With males, there's no evidence it affects sperm quality, but as with any vaccine, it could cause a transient fever which could in turn temporarily affect sperm.

7) What about the allegation that giving the vaccination weakens the dog's immune system immediately afterwards for up to a week? MS: Not true. The purpose of vaccination is to stimulate the immune system. In fact just doing so can also offer slight protection against other unrelated diseases.

8) Or the allegation that one study in pigs showed that giving a vaccine for one virus and then exposing the pig to another respiratory virus made the pigs even sicker with the second virus? MS: This was one study, using a human strain of flu in pigs. There is no data to support such effects in dogs. In humans they use multi-valent flu vaccines that may not match exactly every year.

Flu Facts:

  • Symptoms are similar to tracheobronchitis (kennel cough), however, the cough produced by the flu virus is often soft and moist. Ranging from mild to severe, H3N2 flu starts as an upper-respiratory illness depicted by a persistent cough, clear nasal discharge and low-grade fever combined with lethargy and reduced appetite.
  • An H3N2 infected dog is most contagious during the two- to four-day incubation period when they are shedding the virus in nasal secretions but not showing signs of illness.
  • Virtually all dogs exposed to the virus become infected; 80 percent of dogs develop a flu. like illness and the 20 percent that do not become sick can still spread the virus to other dogs.
  • Sick dogs showing signs of respiratory illness should be separated from other dogs for two weeks.
  • A sick dog transmits the virus to another dog through saliva, coughing and sneezing, contaminated objects such as food and water bowls, toys, collars, and leashes, and by people moving between infected and uninfected dogs.  The virus can travel up to 20 feet through the air.
  • The virus can live on soft surfaces for up to 24 hours and hard surfaces for up to 48 hours.
  • Disinfectants such as Wysiwash and Oxyquat are safe around dogs and help kill virus.

Flu Misconceptions

  • A sheet or cover over your crate will NOT prevent exposure to the canine flu. The virus is largely airborne. If air can get to your dog, so can virus. If a sheet were effective, the veterinary clinic isolation wards would be fine by putting a sheet over the door or in front of the affected dogs' cage. It doesn't work that way. Several handlers whose dogs were infected had either covers over their crates or were using enclosed crates.  In fact, Karan Aurelius' dogs were covered.
  • Showing your own dog's bite to the judge will NOT prevent exposure. It may help. But if judges still touch your dog's cheeks, where he licks, or his body, where he licks, the virus can still be spread by the judge's hands.
  • Rushing to the ring and back outside will NOT prevent exposure. It may help, as your dog is less likely to come nose to nose with a dog possibly shedding virus, but all it takes is inhalation of any virus at any point on his sprint and he may be infected.
  • Avoiding coughing dogs will NOT prevent exposure. Dogs shed the virus before exhibiting symptoms of infection themselves.
  • Giving your dog immune-boosting supplements and vitamins will NOT prevent illness.  If this worked wouldn't we all be taking them?
  • Feeding your dog a healthy diet will NOT prevent infection. Most of the infected dogs were extremely healthy when they were infected. Some ate top commercial diets, some were raw fed, some combined commercial, raw and fresh supplements. Some were kennel dogs, some were house pets, some were active in the field.
  • It's NOT just a "bad case of kennel cough." Yes, some cases are mild. They may have a soft cough for 10 to 30 days. But other cases are severe, with fevers of 104-106 and clinical signs of hemorrhagic pneumonia. About 5 to 8% of dogs die. And they can die with six hours of the first cough.


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