Phylogenetic and pathogenic analysis of a novel H6N2 avian influenza virus isolated from a green peafowl in a wildlife park.

H6 subtype avian influenza virus, which has been circulating among different species, causes considerable concern for both veterinary medicine and public health. We isolated a strain of H6N2 avian influenza virus from healthy green peafowl (Pavo muticus) in Qinghuangdao Wildlife Park in Hebei Province, China, in 2012. A phylogenetic analysis indicated that the isolated H6N2 strain had the same gene constellation as southern China strains, which were predominantly isolated from waterfowl distributed in Shantou, Guangxi, and Hunan in 2001-2010. The isolate showed no and low pathogenicity in chickens and ducks, respectively. However, it replicated efficiently in the lungs and turbinate of infected mice, resulting in thickened alveolar septa and moderate interstitial pneumonia. This finding raises concerns that the H6N2 subtype maybe evolve into a novel endemic avian influenza virus. Therefore, periodical surveillance of avian influenza viruses must be undertaken to monitor the advent of novel viruses.