Analysis of molecular characteristics of the pathogen causing 5 influenza outbreaks

Abstract

Abstract: Objective To conduct a genome-wide genetic characteristics analysis of 11 strains of influenza A H1N1 virus in 2023,in order to provide a basis for scientific prevention and control of H1N1 influenza. Methods Collect samples of influenza outbreaks from February to March 2023,separate and cultivate samples with Ct<30,construct libraries for eleven strains of A/H1N1 influenza isolates,and perform sequencing analysis. The vaccine strains and global representative strains of influenza A H1N1 were downloaded from the national center for biotechnology information（NCBI） database,and BioAider V1.521 software was used for sequence alignment and analysis of amino acid mutation sites. MEGA 11.0.13 software was used for multiple sequence alignment and construction of a phylogenetic tree,and TreeTime online software was used to estimate the molecular evolution rate of the HA and NA genes. Results The Q206E mutation occurred in the antigenic determinant cluster Sb region of the hemagglutinin（HA） gene,and mutations were observed in the L475M site of the polymerase basic protein 2（PB2） and the I397M site of the polymerase basic protein 1（PB1）,which might affect the pathogenicity and toxicity of the virus. Genetic evolution analysis revealed that 11 local strains of influenza A H1N1 virus had close genetic distance with vaccine strain A/Victoria/2570/2019,reference strains A/Rochester/U122/USA/2020 and A/Rochester/U133/USA/2020,and they all belonged to Clade I branch. Whole genome evolutionary analysis showed that the HA and neuraminidase（NA） genes followed a strict molecular clock. Conclusion At present, the influenza viruses are still undergoing continuous mutation. The vaccine strain A/Victoria/2570/2019（H1N1） still provides protection to the population. It is necessary to continue strengthening drug resistance monitoring,timely grasp the genetic characteristics of influenza viruses,and carry out scientific prevention and control.

Key words: Influenza A H1N1, Whole genome sequencing, Homology analysis, Phylogenetic tree, Amino acid mutation site

CLC Number:

CHEN Shiyao, SUN Yihua, WEI Ye, CHEN Lu, LI Li, JI Xiaolei. Analysis of molecular characteristics of the pathogen causing 5 influenza outbreaks. [J]OCCUPATION AND HEALTH, 2025, 41(7): 893-898.

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