Evolution of hemagglutinin gene of influenza A/H1N1(09pdm) virus in China, 2009−2015

Abstract:

[Objective] To analyze the tendency, genetic characteristics and evolution of hemagglutinin gene of the influenza A/H1N1(09pdm) virus circulating in China between 2009 and 2015. [Methods] Epidemiological data of A/H1N1(09pdm) and hemagglutinin sequences were analyzed. Epidemiological data were collected from the website of Chinese National Influenza Center and HA sequences of the influenza A/H1N1(09pdm) virus were filtered from The Global Initiative on Sharing All Influenza Data and National Center for Biotechnology Information. Phylogenetic trees and the mutations of amino acids were constructed and analyzed by biological software. [Results] A total of 4 activity influenza peaks emerged between 2009 and 2015. Compared with vaccine strain A/California/07/2009(H1N1), the HA gene sequence of 2009?2015 shared different nucleic acid sequence similarity decreased with years. The phylogenetic analysis showed that HA gene of the same year clustered nearly on the phylogenetic tree. The HA gene from 2011 divided into two clusters. The amino acid substitutions of HA protein were observed in all four epitopes. Position 203 in epitope Ca, position 163 in epitope Sa and position 185 in epitope Sb changed into new amino acid gradually. The positive pressure site was observed HA protein site 240 in each year except 2010 and 2012. [Conclusion] The influenza A/H1N1(09pdm) has become one of the main subtypes in China. The HA gene and amino acid changes gradually and this emphasize the importance of reinforcing virus surveillance.