This disease has been in the news in the past couple of weeks because there is a large outbreak ongoing in the southeast, including North Carolina.
This outbreak originated at two dog shows that took place in Georgia and Florida. The H3N2 influenza virus that is responsible was first diagnosed in the United States in the Chicago area in 2015. It is extremely contagious because it is a new virus; dogs do not have any naturally occurring antibodies to the virus.
The virus is spread through the air -a cough or sneeze can carry the virus up to 20 feet away- or contact with hard surfaces such as bowls and cages. A dog who has been infected with influenza can be shedding the virus for a day or two before they even start showing symptoms which makes it that much easier for the disease to spread.
Approximately 80 percent of dogs who are exposed will become infected, with the incubation period being about 3-4 days. Infected dogs can continue to shed the virus up to 3 weeks. Most dogs will develop a cough, fever, and nasal discharge. More seriously affected dogs can develop pneumonia.
There have been two fatalities in North Carolina so far (one from Raleigh, one from the coast). H3N2 influenza primarily affects dogs, though in previous outbreaks there have been a few reported cases in cats as well.
There is a vaccine available for dogs that is given as an initial dose and then a booster 3 weeks later. It takes several weeks for the body to fully respond to any vaccine so it is advisable to be sure your dog’s vaccinations are up to date before any planned trips.