Analysis of NA gene variation of influenza A(H1N1) virus isolated in Chongqing from 2011 to 2016

Abstract

Objective To research the gene characteristics of neuraminidase(NA) gene of influenza A(H1N1) virus of Chongqing from 2011 to 2016. Methods Forty-three H1N1 influenza virus strains isolated from 2011 to 2016 were chosen according to the different time and places of isolation. NA genetic sections were amplified by RT-PCR and sequenced, and then the sequences of nucleic and amino acid were analyzed. Results Phylogenetic analysis indicated that the relationship between H1N1 viruses from 2011 to 2016 and the vaccine strain was close to each other. Compared with the vaccine strain A/California/07/2009(H1N1), the homologies in nucleotide and amino acid sequences for NA gene were 97.9%-99.4% and 96.8%-98.9%, respectively. Most of the strains had the same eight potential glycosylation sites as the vaccine strains, and some strains got new potential glycosylation sites at NA protein site 42, while some lost their potential glycosylation sites at NA protein site 386. Conclusions The changes of H1N1 NA gene had increased year by year, but H1N1 viruses in Chongqing area were still sensitive to Daffy. And monitoring the drug resistant viruses should be strengthened, in order to provide measures against H1N1 viruses. Key words: H1N1; Influenza Virus; Sequence analysis; NA gene