Canine Influenza Very Contagious

Risk is highest where dogs congregate, such as doggy day care facilities, dog parks, grooming parlors, training classes, dog shows, and boarding kennels.

A dog becomes infected within a few hours of exposure and shows clinical signs two to five days later. Clinical signs include coughing, sneezing, loss of energy and appetite, fever, and discharge from the nose and eyes. ArtPhoto21/Shutterstock

Q: My dog’s annual physical is coming up soon, and my veterinarian is sure to recommend the flu shot, which I’ve declined in the past. I’m rethinking that after a friend’s dog came down with the disease. Please tell me about dog flu.

A: Dog flu, formally known as canine influenza, was first recognized in the United States in 2004. It is caused by two strains of the influenza A virus: H3N8 and the more common H3N2.