Two dogs in southwestern Ontario have tested positive for a strain of canine influenza in what health officials are calling the virus's first known incursion into Canada.

The Windsor-Essex County Health Unit said the dogs were brought to Canada from South Korea through the United States late last month and were showing signs of respiratory disease during a veterinary exam the next day.

A small number of dogs that came into close contact with the pair also have mild respiratory disease but test results for those animals are not yet available, the agency said.

It says the H3N2 canine influenza virus is highly transmissible between dogs and has become widespread in parts of Asia and caused outbreaks in some U.S. locations, particularly in shelters.

The health unit said most dogs who develop the disease don't get seriously ill, and typically show symptoms similar to those from other respiratory infections such as the so-called kennel cough.

Dogs who show symptoms of respiratory disease, such as decreased appetite and fever, should be kept away from other dogs for at least two weeks to limit spreading, it said.

Health officials said there is no known human risk from the virus, but note the risk that it might mix with human seasonal influenza viruses is "a potential concern."

"The investigation and response are ongoing, and at this point, the concern mainly involves the imported dogs and their close contacts," they said in a statement.

"Affected and exposed dogs are being confined by their owners to help prevent further spread. However, dog owners in Windsor and Essex County should be vigilant and watch for signs of respiratory disease in their dogs, particularly dogs that frequently have contact with other dogs."