SEROLOGICAL SURVEY OF INFLUENZA A VIRUS (H3) INFECTION IN DOGS IN BANGKOK BY USING NP-ELISA TOGETHER WITH HI TEST

Canine influenza virus subtype H3N2 (canine-H3N2) outbreaks have been reported in dogs in China and Korea since 2009. In Thailand, canine-H3N2 infection in pet dogs was first reported in 2012. In this study, a serological survey of influenza A virus (IAV) infection in dogs in Bangkok and vicinities was conducted during December 2012 to November 2013. A total of 9,891 sera samples was examined for IAV antibodies by using an anti-nucleoprotein antibodies ELISA assay (NP-ELISA) and haemagglutination inhibition (HI) testing with canine-H3N2, human-H3N2 and human-pH1N1 virus antigens. Our result demonstrated that 164 (1.66%) of 9,891 sera samples posed antibody against IAV by NP-ELISA test. For HI test, 36.56% of the positive and suspected NP-ELISA samples posed HI titer to IAV subtypes canine-H3N2 (12.20%), human-H3N2 (1.22%) and human-pH1N1 (23.17%). Interestingly, the evidence of co-infection of IAVs (2.44%) were detected in pet dogs composing co-infections between canine-H3N2 and human-pH1N1 viruses (1.22%) as well as human-H3N2 and human-pH1N1 (1.22%), suggesting the risk for reassortment among IAVs. In summary, IAV infection could be observed in Thai dog populations and evidence of exposures to canine-H3N2, human-H3N2 and human-pH1N1 was demonstrated. Therefore, the transmission of IAVs between dogs and humans should be closely monitored and minimized.