Dogs have their own version of flu virus that is making the rounds. So far, it has been confirmed in several US states.

From the AVMA
Backgrounder: Canine influenza

From the About.com Veterinary Medicine site:

Originally discovered in 2004, the canine influenza virus is believed to have jumped from horses to dogs in Florida. This virus, H3N8, is a subtype of the influenza A virus, a highly contagious pathogen that can cause disease by itself or in conjunction with other respiratory pathogens. Full article

Related: Canine H3N8 Influenza Vaccine