Question: how long are dogs contagious with dog flu?
Answer: The incubation period of canine influenza is approximately 2-to-4 days from initial exposure to the dog flu virus. Viral shedding starts to decrease after the fourth day, but dogs with H3N8 remain contagious for up to 10 days after exposure, and dogs with H3N2 remain contagious for up to 26 days.