Submitted to: Influenza and Other Respiratory Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2010
Publication Date: August 25, 2010
Citation: Mckinley, E.T., Spackman, E., Pantin Jackwood, M.J. 2010. The pathogenesis of H3N8 canine influenza virus in chickens, turkeys and ducks. Influenza and Other Respiratory Viruses. 4:353-356. Interpretive Summary: Canine influenza virus (CIV) was first diagnosed in greyhounds in 2004, in Florida and has since spread within dog populations throughout the U.S. where is has become endemic in kennels and animal shelters in some regions. CIV is believed to be an equine influenza virus that somehow transmitted to, and subsequently adapted to dogs. It has not previously been determined whether CIV can be transmitted to domestic poultry, chickens, turkeys or ducks, are which are susceptible to type A influenza virus from numerous species. Since influenza infection of poultry can cause substantial economics losses, it is critical to determine whether dogs can serve as reservoirs of influenza for these species. Furthermore, any time influenza crosses species there is a potential for the new strain to "blend" with a strain which is already infecting that host, which can lead to viruses with novel disease and virulence characteristics. To evaluate the susceptibility of chickens, turkeys and ducks to CIV experimental studies were conducted. No disease was observed in any of the birds, nor was virus detected in their respiratory or intestinal tracts. Finally, none of the birds developed antibody to CIV, indicating that chickens, turkeys and ducks can not be easily infected with CIV and that dogs are not likely to serve as reservoirs of influenza for poultry.
Technical Abstract: Canine influenza virus (CIV) of the H3N8 subtype has emerged in dog populations throughout the U.S. where is has become endemic in kennels and animal shelters in some regions. It has not previously been determined whether the canine adapted virus can be transmitted to domestic poultry, which are susceptible to type A influenza virus from numerous species. To evaluate the pathogenesis of CIV in poultry, four-week old specific pathogen free (SPF) chickens, three-week old SPF turkeys and three week of SPF ducks were inoculated with 105 50% egg infectious doses per bird by the intra-choanal route. The birds were observed daily and at 2 and 4 days post inoculation (DPI) two inoculated birds and one sham inoculated control bird were euthanized and necropsied to evaluate gross lesions and to collect tissues for microscopic examination. Cloacal and oral swabs were collected at 2, 4 and 7 DPI to evaluate virus shed by real-time reverse transcriptase polymerase chain reaction (RT-PCR). Two-weeks post infection sera was collected from all remaining birds for type A influenza antibody detection. Clinical signs and gross lesions were absent in all three species. Antibody was not detected in serum from any bird of any species and oral and cloacal swab material was negative for virus. Chickens, turkeys and ducks were not susceptible to infection with CIV by simulated respiratory exposure route with the dose administered.