Seroprevalence of canine influenza virus (H3N8) in Iditarod racing sled dogs.

We conducted a cross-sectional convenience sampling study of dogs racing in the 2010 Iditarod to determine the seroprevalence of canine influenza virus (CIV) in the sled dog population. Questionnaires were completed detailing medical and CIV vaccination history, kennel size and location, travel history, and social interactions for each team. A total of 399 dogs were tested for CIV antibodies by hemagglutination inhibition assay. None of these, including 39 samples from dogs reported as CIV vaccinated, were seropositive for CIV antibodies. All of the vaccinated dogs were also negative on virus microneutralization assay. Risk factors for CIV seropositivity could not be determined due to a lack of positive samples. This is the first published study investigating the prevalence of CIV in sled dogs and additional studies are warranted to assess CIV infection among racing sled dogs and to evaluate the ecology of CIV and the vaccine efficacy in this population of dogs.