Virulence of a novel reassortant canine H3N2 influenza virus in ferret, dog and mice models = Virulence of a novel reassortant canine H3N2 influenza virus in ferret, dog and mice models

다국어 초록 (Multilingual Abstract)

The outbreak of a canine influenza virus (CIV) H3N2 reassortanted from pandemic (pdm) H1N1 and CIV H3N2 in companion animals has underscored the urgent need to monitor CIV infection for potential zoonotic transmission of influenza viruses to humans. In this study, we assessed the virulence of a novel CIV H3N2 (VC378) from a pdm H1N1 and CIV H3N2 coinfected dog in ferrets, dogs, and mice. Significantly enhanced virulence of VC378 was demonstrated in mice, although the transmissibility and pathogenicity of VC378 were similar to those of classic H3N2 in ferrets and dogs. This is notable because mice inoculated with an equivalent dose of classic CIV H3N2 showed no clinical signs and no lethality. We found that the PA and NS gene segments of VC378 were introduced from pdmH1N1, and these genes included amino acid substitutions; PAP224S and NS-I123V, that were previously found to be associated with virulence enhancement in mice. Thus, we speculate that the natural reassortment of CIV between pdm H1N1 and CIV H3N2 can confer virulence and that continuous surveillance is needed to monitor the evolution of CIV in companion animals.