Influenza viruses in dogs - two canine viruses that arose from viruses of horses and of birds

A second model system that we are examining is the emergence of two different canine influenza viruses (CIV) in dogs. In one case a CIV emerged after transfer of an H3N8 equine influenza virus (EIV) to greyhounds around 2000, after which the virus spread widely in dogs in households and animal shelters and kennels. Those studies are examining the properties of the canine virus, to determine whether it is a host-adapted variant, and to follow the evolution of the virus in dogs during the 16 years in which it has been continuously passaged in dogs.

A second CIV (the H3N2 variant) arose in China when an influenza of birds transferred to dogs, and that virus subsequently spread to Korea, and was transferred to the USA in 2015. That virus has caused outbreaks in various regions of the USA after 2015, but has been circulating mostly in the Chicago area. We have been examining that virus for its properties, and are seeking to define how it became able to infect can cause disease in dogs.

In these studies of the two canine influenza viruses we are also examining why these new viruses have emerged in dogs, and also attempting to understand the host barriers that normally prevent infection. The viruses in dogs appear to be most commonly found in large animal shelters or kennels, and in general they cannot maintain themselves in household dogs.