As this information is appearing at about the same time the Swine Influenza is in the news, there may be some inclination for dog owners to confuse the two viruses. Swine Influenza is an H1N1 virus. Canine Influenza is an H3N8 virus. They are NOT the same virus. The Canine Influenza virus (H3N8) is the equine influenza virus which has mutated in such a manner that it is now capable of infecting dogs. This mutation occurred about three years ago and the infection was first diagnosed in Greyhound racing kennels in Florida. As Greyhounds move around a lot to the various race tracks, it was not long until the Canine Influenza virus was a real issue in the doc racing business. Canine influenza is highly contagious and has caused the complete shut down of multiple race tracks, boarding facilities, and veterinary clinics.
The primary clinical sign of canine influenza is a moist or dry cough that ranges between fairly mild to very severe. About 80% of the dogs exposed to the virus will have clinical signs (cough, snotty nose) of the disease. The other 20% will be clinically normal but are still capable of spreading the disease. The cough can last for 4-6 weeks despite treatment. Of the 80% that exhibit clinical signs, 20% of them will develop high fevers and a secondary pneumonia. The pneumonia can be expected to be fatal in 1% - 3% of the cases. Fatalities result from a non-responsive secondary pneumonia.
A major and disturbing characteristic of the disease is that it is most contagious 24 hours before any clinical signs are observed. This means that your dog can be exposed to the virus by a dog that is still 100% clinically normal.
There is no specific medication that will treat canine influenza. All treatment is supportive in nature and directed toward minimizing clinical signs while the disease runs it course.
As this is a very new virus appearing in the dog world, very few dogs have any immunity against the disease. Only the dogs which have had the disease and have recovered or the dogs that have been vaccinated against the disease are immune. There is a vaccine for use against the disease. The FDA considers the vaccine to be a “provisional” vaccine because it has been on the market less than 2.5 years. At this time the veterinary profession does not recommend universal vaccination against the disease. However, the vaccine is recommended for dogs that are frequently boarded, groomed, go to dog parks, travel extensively, or are frequently congregated with groups of unfamiliar dogs.
As the cough sounds much like the cough that results from many other canine respiratory disease, diagnosis of the disease cannot be confirmed by a physical examination. Laboratory tests are required to confirm the disease.
Although the disease is not usually fatal, all of the dogs exposed to the virus are expected to become sick and in multiple dog households or in kennel situations, it can rapidly become quite expensive to treat.