Objective: To determine the seroprevalence of antibody against canine influenza virus H3N8 in a group of pet dogs that participate in flyball in Pennsylvania. DESIGN-SEROLOGIC SURVEY: Animals-Dogs attending a flyball tournament in Downingtown, Pa, from November 13 to 14, 2009. Procedures-Blood samples were collected from dogs following owner consent. Medical, travel, and activity history of the dogs for the previous 10.5 months was obtained from owners. Serum was harvested and submitted to Cornell University Diagnostic Laboratory for measurement of antibody against canine influenza virus H3N8 via hemagglutination inhibition testing.
Results: Serum samples were obtained from 100 of 256 dogs participating in the flyball event. Although 3 of the 100 (3%) samples had positive results for antibody against canine influenza, none of the associated dogs had respiratory signs of infection (eg, coughing, sneezing, or nasal or ocular discharge) in the 10.5 months prior to testing. Eleven dogs had a history of respiratory signs, but none of those dogs had antibody against canine influenza H3N8. In addition, none of the study dogs had been vaccinated against canine influenza H3N8.
Conclusions and clinical relevance: Although canine influenza is considered enzootic in certain areas of the country (eg, Pennsylvania or New York), this study identified a low seroprevalence in dogs considered at high risk for infection given their life conditions and geographic origins. More research is warranted to elucidate the prevalence of exposure to the H3N8 virus in competitive sporting dogs and determine whether vaccination is warranted in such dogs.