Molecular and phylogenetic analysis of human avian influenza A (H7N9) virus infection in Zhejiang province during 2013 and 2015 / 中华临床感染病杂志

ABSTRACT

Objective To analyze the molecular characteristics of human pathogenic avian influenza A H7N9 virus.Methods The gene sequences of avian influenza A H7N9 virus (30 human-originated and 15 avian-originated) isolated in Zhejiang province from 2013 to 2015 were downloaded from Global Initiative on Sharing Avian Influenza Data ( GISAID), and then the evolution characteristics, the sites related to receptor binding, virulence and drug resistance of H7N9 virus were analyzed by MEGA 6.0 software. Results There were minor differences in HA and NA genes between human H7N9 virus strains and poultry reference strains in Zhejiang province with the homology of 98.0%-100.0% and 97.4%-100.0%, respectively.Viral amino acid variation showed that 30 representative strains had mutations at 226 (Q226L/I) and 186(G186V) sites in HA protein, and all strains isolated from 2015 had A134V mutation;one strain had R294K mutation in NA gene;19 strains had E627K mutation in PB2 and 2 strains had D701N mutation;mutation S31N was found in M2 gene in all isolates; and all HA cleavage sites were PEIPKGR↓GLF, indicating low pathogenic strain.Conclusions The homology of HA and NA genes is high between poultry reference strains and human H7N9 virus strains in Zhejiang province during 2013 and 2015.Strains have some significant mutations of amino acid in HA and NA protein.All isolates show ion channel inhibitors ( Amantadine) resistance, and some isolates show resistance mutations with neuraminidase inhibitors.