A highly infectious dog flu that has spread rapidly across Asia and parts of the U.S. has made its way into Canada.

Two dogs in Essex County, Ontario, have H3N2 canine influenza, according to the Windsor-Essex County Health Unit, and two others are showing symptoms though the infection has not been confirmed in those canines.

Officials said the dogs were imported from South Korea, through the U.S. and were showing signs of respiratory disease the day after they arrived when they were examined by a veterinarian.

A small number of other dogs that had close contact with the affected canines also have mild respiratory disease, said WECHU, but test results from those animals are not yet available.

"In general, we know this is a flu that has been around in Asia for quite a while and has moved into the U.S. a few years ago," said Scott Weese, a professor and infectious disease specialist at the Ontario Veterinary College at the University of Guelph. "It's been causing problems in the U.S. for a few years and we haven't seen it in Canada until this recent incident."

No human risk

The health unit said there is no known human risk, but officials are worried that a dog infected with H3N2 could also contract a human flu, and those strains could combine to create a new virus.

"It's pretty unlikely to happen, but that's the main public health concern," said Weese.

Distinguishing the canine flu is difficult in dogs, said Weese, because the symptoms are similar to other respiratory infections like kennel cough.

"It's a flu-like illness. It gives them fever, they feel pretty run down, they get a cough which is often the most remarkable sign. In most dogs that's it. It runs its course," said Weese.

But like the flu, it could cause complications for older dogs, or those canines with existing health problems.

What to do

Weese said that if you suspect your dog has influenza, to call the vet first.

"If the vet knows, they can handle the dog with some precautions," said Weese. "What we don't want to see is the dog that has the flu transmit it to other dogs."

He said the reason for alerting the public now is to make sure the influenza stays contained, and does not spread to other dogs.

The WECHU said the infection can spread quite easily among dogs, and a few important points should be noted: