5 more cases of canine flu have been confirmed in dogs in Windsor-Essex.
Health unit testing of dogs exposed to the initial 2 animals imported from South Korea came back positive.
The H3N2 virus was identified in the first dogs earlier this week.
The affected and exposed dogs are being confined by their owners to help prevent further spread.
The health unit says canine influenza virus is of concern because it is highly transmissible between dogs, particularly in areas like Canada where dogs don't have natural immunity and where vaccination is rare.
Canine flu doesn't usually result in the dog becoming seriously ill.
The health unit points out the canine version of H3N2 virus is different than the human one and there is no known risk to people.