April 5, 2016
Categories: Shelter Medicine

There’s a new cause of canine respiratory disease in town, and it’s something animal shelters need to sit up and take notice of.

As if the original canine influenza, first identified in 2004 and dubbed H3N8, wasn’t bad enough, the new virus — N3N2 — presents special challenges both to owned pets and to dogs in shelters.

“There is evidence that dogs infected with the new H3N2 canine influenza virus can shed virus and remain contagious for up to 3 weeks,” explained Dr. Cynda Crawford, director of the Maddie’s Shelter Medicine Program at the University of Florida, and one of the reseachers who identifed the original strain.

“This is in sharp contrast to the original H3N8 canine flu virus where virus shedding stops after 1 week. The longer shedding period for the H3N2 virus impacts management of infected dogs in that they must remain in isolation from other dogs for at least 3 weeks.”

Dr. Crawford pointed out that’s it’s very challenging for shelters to keep these dogs isolated in their facility for that long, and that the risk of exceeding the facility’s capacity for care increases significantly curing that time.

What can shelters do? “Recruiting rescue groups, foster homes, and other facilities for housing infected dogs until they are no longer contagious is a valuable ancillary approach for successful management and resolution of a shelter outbreak without sacrificing capacity for care,” she said.

H3N8 was the first influenza virus known to affect dogs. In March of 2015, veterinarians in the Chicago area reported seeing some kind of respiratory infection that made dogs a lot sicker than they would have expected from canine flu or other respiratory infections they were used to seeing in dogs. Some dogs died, and the infections seemed to be centered around the city’s dog parks.

The pathogen behind these infections was eventually identified as a strain of CIV previously found in Asia, possibly carried to the U.S. via air travel by pet or rescue dogs.

“When canine influenza is circulating in a community, dogs in the local shelters are at high risk for infection,” said Dr. Crawford. “If one infected dog from the community is admitted into the shelter, the highly contagious virus can infect nearly every dog in the shelter, causing an explosive increase in the number of coughing dogs within two weeks.

“Experience with managing canine influenza epidemics in shelters over the years has shown that the best course of action to stop virus transmission is to temporarily stop movement of dogs in and out of the shelter. Stopping admission establishes a clean break by preventing perpetuation of the virus in new dogs. Stopping release prevents dissemination of infected dogs back out into the community.”

Can shelters really stop the virus in its tracks? “Many shelters have eliminated canine influenza with minimal loss of life following this approach” she said. “To aid capacity for care, shelters have successfully enlisted rescue groups and foster homes to care for infected dogs in an isolated manner while the virus runs its course.”

Update: After our interview with Dr. Crawford but prior to publication of this post, the University of Wisconsin announced the new canine influenza virus can also infect and sicken cats.

Also of interest:

Respiratory Infections in Shelters: Beyond Kennel Cough

Webcast: What Animal Shelters Need to Know About the Canine Influenza Outbreak

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