Canine influenza viruses (CIV H3N8 and CIV H3N2) cause a respiratory infection in dogs that is often referred to as 'Canine Flu'. Canine influenza virus (CIV) is one of the causes of CIRDC (Canine Infectious Disease Complex), also known as Kennel Cough. Two different canine influenza viruses have been isolated in the US: CIV H3N2 & CIV H3N8.
CIV H3N2 emerged in the Chicago outbreak of 2015. This virus is of avian origin and not related to the earlier CIV H3N8 virus, which is of equine origin. Therefore, dogs at risk should be vaccinated against both viruses.
Canine influenza viruses are relatively new viruses, so virtually all dogs are susceptible to infection when they are newly exposed because they have not built up natural immunity. Most dogs that develop CIV infection have a mild illness, but some dogs become very sick and require treatment.
Read more on canine influenza here: www.doginfluenza.com/.