It’s Not Just “Flu Season” for People…but for dogs, too!!!
Each of the CIV epidemics ultimately derives from a single cross-species transfer event, with the H3N8 subtype from horses, while the H3N2 subtype is assumed to have arisen directly from a virus in an avian reservoir. A recent study showed that in Southern China dogs may be frequently infected by various swine, canine and other influenza viruses.1
Vaccination Against Canine Influenza Viruses
Vaccines to both strains of influenza virus in dogs are available. Those are inactivated virus vaccines that are given as two doses, three or more weeks apart. Combined (bivalent) vaccines that contain both the H3N2 and H3N8 strains are also available. The most important virus is currently the H3N2 strain as that is still circulating widely in the USA. Vaccination is most recommended for use in dogs that attend doggy day cares, travel widely, spend time in kennels or frequently go to dog parks. NOTE: 2 DOSES OF VACCINE ADMINISTERED AT LEAST 2 WEEKS APART ARE NECESSARY TO CONFER ANY PROTECTIVE IMMUNITY. I ADMINISTER THE BI-VALENT VACCINE TO MY PATIENTS….
The influenza viruses that infect dogs are a threat to canine health, and it now appears that dogs are a susceptible host, so that we should consider influenza viruses in cases of contagious respiratory disease in dogs. The two CIVs both cause relatively uncomplicated upper respiratory tract diseases in dogs, with relatively short periods (3 to 4 days) of high level viral shedding, but with clinical symptoms continuing for several days or more. The viruses appear to require relatively close contact to give transmission, so that in most populations of household dogs the viruses are not maintained over long periods. However the viruses may be able to continue to spread for longer periods within large animal shelters, kennels, or in meat dog farms in Asia. The H3N8 virus is now only present in dogs at very low levels if it is present at all. The H3N2 virus has caused a number of widespread outbreaks, apparently due to the reintroduction of the virus from Asia. Vaccinations provide a level of protection against CIV infection or disease, and should be given to animals that are particularly likely to be exposed, or which might suffer more severe disease.