Two genotypes of H1N2 swine influenza viruses appeared among pigs in China

Background: H1N2 is one of the main subtypes of influenza, which circulates in swine all over the world. Objectives: To investigate the prevalence and genetic of H1N2 in swine of China. Study design: Two H1N2 swine influenza viruses were isolated from Tianjin and Guangdong province of China in 2004 and 2006, respectively. The molecular evolution of eight gene segments was analyzed. Result: A/Swine/Tianjin/1/2004 has low identity with A/Swine/Guangdong/2006; in the phylogenetic tree of PA gene, A/Swine/Guangdong/1/2006 and A/Swine/Guangxi/1/2006 along with the H1N2 swine isolates of North America formed a cluster: and A/Swine/Tianjin/2004 and A/Swine/Zhejiang/2004, along with the classical HIM swine isolates formed another cluster; except that NA gene of A/Swine/Tianjin/1/2004 fell into the cluster of the H3N2 human influenza virus, indicating the reassortment between H3N2 human and H1N1 swine influenza viruses. Conclusion: Two different genotypes of H1N2 appeared among pigs in China. A/swine/Guangdong/1/06 was probably from H1N2 swine influenza viruses of North America; while A/swine/Tianjin/l/04 maybe come from reassortments of classical H1N1 swine and H3N2 human viruses prevalent in North America. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.