Molecular Characterization of Hemagglutination Gene of Influenza A/H3N2 Virus in Hunan Province in 2007～2008

Objective To investigate the molecular characterization of influenza A (H3N2) virus in prevalence in Hunan Province in 2007～2008. Methods Twenty-nine strains of influenza A (H3N2) virus were isolated from the samples in influenza surveillance. Hemagglutination genes of 29 strains were amplified by RT-PCR method. The RT-PCR products were purified and sequenced. And then the sequences were analyzed phylogenetically and compared with WHO influenza vaccine strains. Finally the phylogenetic tree was drawn according to deduced amino acid sequences. Results As compared with the northern hemisphere vaccine strain A/Wisconsin/67/05 in 2007～2008,the variation sites of influenza strains isolated in 2007 were G50E,S138A,K140I,R142G and N144D,and the variation sites of strains isolated in 2008 were G50E,S138A,K140I and L157S. But as compared with the northern hemisphere vaccine strain A/Brisbane/10/07 in 2008～2009,the variation sites of influenza strains in 2008 were K140I and L157SA. Conclusions HA1 gene variation of influenza A (H3N2) viruses in Hunan Province in 2007～2008 was recorded,which suggested it was the main cause leading to the spread of influenza.