Vaccine for New Dog-Flu Strain Hitting Arizona "Not Appropriate" for All Patients

Vaccines approved recently for a new strain of dog flu might take away some of the worry for some pet owners but could do more harm than good, says a local veterinarian.

"It's not appropriate for every patient," says Dr. Billy Griswold, who owns Priority Pet Hospital in Gilbert with his wife, veterinarian Karin Burns. "There could be a risk from using the vaccine."

Dogs can catch the contagion "anytime they have nose-to-nose contact with dogs of unknown health status."

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Dog owners concerned about the flu ought to first have a talk about the animal's lifestyle with their local vet, Griswold says.

"There's a lot more risk [from the flu] at boarding kennels or if they spend more time at dog parks," he says. But if a dog stays at home most of the time, the vaccine might not be worth the trouble or cost.

The H3N2 strain of canine influenza appeared for the first time in the United States in March, recognized by scientists as similar to a known canine virus from South Korea. More than 1,000 dogs in the Chicago area came down with flu symptoms, even if they'd been vaccinated previously against another strain of flu known as H3N8. Five dogs died from the outbreak.

The latest virus is believed to be even more contagious than H3N8. It spread across the country over the next several months, with several cases noted in Arizona.

"At this point, a lot of dogs at risk have been exposed," says Dr. Alex Seguin of IDEXX Laboratories in Maine. The company began offering a test for H3N2 to animal clinics in May. In April, about 20 percent of test samples sent in by vets around the country were positive for the new strain.

"It's quieted down since then," Seguin says.

But the virus still is present in the pet community and could present a health problem for some dogs.

Dogs can catch the contagion "anytime they have nose-to-nose contact with dogs of unknown health status," Griswold says.

More than half of all dogs exposed to either strain of flu virus will show at least some symptoms, he says. About 10 percent of these dogs "get pretty sick." As with humans, the flu in dogs typically affects the respiratory system and causes fever, lethargy, and loss of appetite. 

It's rare, but possible, for dogs to die of the flu, experts say. Dogs and cats transmit the virus, according to Cornell University's website, but U.S. cats haven't yet gotten sick from it. Humans can't contract the virus.

Although risk of a truly dangerous outbreak seems to have passed, news about dog flu has flared up in recent weeks because of the new vaccines for H3N2. Last month, Merck Animal Health and Zoetis announced that they had received conditional approval for a vaccine against H3N2. The vaccine now is available in various clinics.

But whether the marketing of the vaccine is beneficial to consumers is the source of debate. An article published on the Veterinary Information Network website in 2012 covered criticism of the "hype" that drives vaccine sales.

"It seems to be getting harder to [determine] when a disease is real and when it is being ‘pushed’ by vaccine or drug manufacturers these days," Dr. Margaret Mason, a California vet, wrote in a comment on the website, the article states.

Griswold says his Gilbert clinic would put in an order if enough people wanted the vaccine. So far, he says, no one's requested it.

Cornell virologist Edward Dubovi, who helped identify the new virus, said last month that pet owners need to realize the virus can be serious and act accordingly.

"People moving animals ought to try to minimize contact between their pet and other pets at their destination, Dubovi said. "You shouldn’t take your dog from Chicago to Tucson, Arizona, and immediately put him in a doggy daycare."
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Ray Stern has worked as a newspaper reporter in Arizona for more than two decades. He's won numerous awards for his reporting, including the Arizona Press Club's Don Bolles Award for Investigative Journalism.