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

BackgroundH1N2 is one of the main subtypes of influenza, which circulates in swine all over the world.ObjectivesTo investigate the prevalence and genetic of H1N2 in swine of China.Study designTwo 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.ResultA/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 H1N1 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.ConclusionTwo 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/1/04 maybe come from reassortments of classical H1N1 swine and H3N2 human viruses prevalent in North America.