Australian officials confirmed that the equine influenza virus infecting about 20,000 horses in the country in 2007 also infected dogs that had close contact with the sick horses.

"Dogs that were with or near equine influenza-infected horses were observed with a flu-like illness," said Peter D. Kirkland, PhD, of the Elizabeth Macarthur Agricultural Institute in New South Wales, Australia. "Detailed genetic studies showed the responsible virus was identical to the virus in the horses. If horse owners want to protect their dogs from canine influenza, they should keep dogs away from close contact with infected horses."

The exposed dogs came down with flu-like symptoms, including a harsh cough, nasal discharge, lethargy, and refusal to eat. Although some dogs became quite sick for a short time, none of the dogs died, which differs from the experience in the United States, Kirkland said.

In the U.S., canine influenza H3N8 virus (CIV) is a highly contagious canine respiratory infection that has been confirmed in 30 states and the District of Columbia