This news item is about: Originally found in the U.S. in 2015, H3N2 canine influenza has made its first appearance in Florida. Officials confirmed seven cases of H3N2 canine influenza early last week with six other pending cases of the disease. H3N2 canine influenza is highly contagious and symptoms appear 2 - 4 days after exposure to the virus. Dogs can transmit influenza to other dogs between 1 and 5 days after they initially become infected, so a dog may share the virus with and infect other dogs before it appears to be ill. Cats in the U.S. have occasionally been diagnosed with H3N2 infections.