Influenza In Animals:
Historically, of the domestic pet animals, only Ferrets have been known to be susceptible to infections from the "Flu". That changed in 2005 when a strain of Equine (horse) Influenza was isolated from a group of dogs in Florida showing signs of a severe "kennel cough" (upper respiratory infection), which progressed into pneumonia resulting in the death of several dogs. Then, in November 2009, H1N1 ("swine flu") was isolated from a cat recovering from a severe upper respiratory illness in Iowa, and a second cat on the west coast. H1N1 has also been reported in dogs in China.
It has been known that while most viral infections are very species specific, occasionally a virus will "jump" species, and the influenza virus is no exception.
In early August of 2009, a vaccine was released for the new "Canine Influenza" virus. This vaccine has a probationary license, indicating that it has been tested in a small group of dogs and found to be safe. Before recommending routine use of this new vaccine, we are waiting to see how the vaccine is handled by dogs now that it is in more general use.
The efficacy studies that we have seen show the vaccine to reduce (not eliminate) virus shedding as well as reduce severity of and shorten duration of symptoms of influence (primarily coughing, fever, and "not acting well") in vaccinated dogs compared to non-vaccinated dogs. The vaccinated dogs also had fewer and milder lung changes, showing a degree of protection against influenza pneumonia.
This vaccine will only provide protection against the strain of canine influenza that has been seen so far (H3N8), it will not protect dogs against H1N1 or other influenza strains that may jump into dogs now or in the future.