The “new” version of canine flu (H3N2) that began as a 2015 outbreak in the Chicago area is back in the news.


The latest surveillance data available through Cornell University shows that positive test results have been identified in dogs from 29 states. But even more interesting is the recent report from the University of Wisconsin’s School of Veterinary Medicine revealing that a group of cats housed in a Northwest Indiana shelter have tested positive for the H3N2 canine influenza virus.


According to Sandra Newbury, Clinical Assistant Professor and Director of the Shelter Medicine Program at University of Wisconsin:

“Suspicions of an outbreak in the cats were initially raised when a group of them displayed unusual signs of respiratory disease,” Newbury says. “While this first confirmed report of multiple cats testing positive for canine influenza in the U.S. shows the virus can affect cats, we hope that infections and illness in felines will continue to be quite rare.”


We already knew that feline infections were possible because South Korea cats were infected with this version of the virus when it was first identified, and one cat did test positive for the disease in the United States last year, but now the University of Wisconsin reports that it “appears the virus can replicate and spread from cat to cat.”


 “Sequential sampling of these individual cats have shown repeated positives and an increase in viral loads over time,” Kathy Toohey-Kurth, virology section head at the Wisconsin Veterinary Diagnostic Laboratory says. Eight cats tested positive on consecutive tests. More had similar clinical signs but “recovered quickly before testing and tested negative.”


Dogs in the shelter did have H3N2 canine influenza when the feline infections were diagnosed, but the cats were housed in a separate part of the facility and the “cat areas were cleaned prior to cleaning the dog areas.” This just goes to show how contagious this particular flu virus can be.


Symptoms in infected cats have been similar to those seen in dogs and include “runny nose, congestion, and general malaise, as well as lip smacking and excessive salivation. Symptoms have resolved quickly and so far the virus has not been fatal in cats.”


I find this development fascinating because it goes to show how things change in the flu arena. Just a couple of months ago I was telling cat owners that it didn’t look like they had anything to worry about when it came to canine H3N2 flu. There is certainly still no reason to panic, but if your cat does develop symptoms consistent with the flu, a trip to the veterinarian is called for, particularly if the cat has been in a shelter setting or around flu-infected dogs.


We simply don’t know whether this outbreak in cats will turn out to be an isolated event or a harbinger of things to come. Only time will tell.