http://shulervetclinic.com/contact-us Mount Pleasant SC veterinarian, Dr. Laura Shuler of Mount Pleasant Animal Hospital and Shuler Veterinary Clinic discusses the relatively new canine disease H3N8. In layman's terms, it is the dog flu. Canine influenza, H3N8, is species specific which means it is not communicable to cats, humans, etc. It is, however, very contagious dog to dog and can cause anything from mild flu symptoms up to life threatening conditions.