Genetic characteristics analysis of the whole genome of influenza B virus in Liuzhou City from 2022 to 2023
objective To analyze the genetic characteristics of the whole genome of the influenza B virus in Liuzhou City from 2022 to 2023,understand the variation of influenza B virus in Liuzhou City and its compatibility with the vaccine strains recommended by WHO.Methods Bioinformatics software such as DNAStar and MEGA were used to compare the complete gene sequences of 31 isolated influenza B virus,construct a gene evolutionary tree,and analyze homology and amino acid site variations.Results The influenza B virus isolated in Liuzhou City in 2022 belong to the C.1 sub-branch.Only the neuraminidase(NA),matrix protein(MP)and polymerase A(PA)gene fragments share the same evolutionary branch as the northern hemisphere vaccine recommended strain B/Washington/02/2019 from 2020 to 2022.The influenza B virus in 2023 belonged to the C.5.6 or C.5.7 sub-branch,and all eight gene fragments were in the same evolutionary branch as the B/Austria/1359417/2021 recommended for the 2022 to 2024 vaccine.Relative to the vaccine recommended strain B/Austria/1359417/2021,the amino acid variation in the hemagglutinin(HA)gene of the influenza B virus isolated in Liuzhou City from 2022 to 2023 had epidemiological significance in the antigenic determinants and receptor binding sites.Respectively the Ha and Na proteins of 31 influenza B virus isolated from Liuzhou City did not show glycosylation insertion or deletion,and there were no mutations in the catalytic activity site and resistance site of Na protease.Some influenza viruses had amino acid mutations at key sites of the non-structural protein(NS)and nucleoprotein(NP),and the PA,polymerase B1(PB1)and polymerase B2(PB2),which composed RNA polymerase,had two main common variation patterns.Conclusion The influenza B virus isolates from Liuzhou City in 2022 was poorly matched to the northern hemisphere vaccine recommended strain B/Austria/1359417/2021,and the influenza B virus isolates from Liuzhou City in 2023 was well matched to the 2023 Northern Hemisphere vaccine recommended strain B/Austria/1359417/2021.The variation of amino acids in the antigenic determinants and receptor binding of HA protein of influenza B virus may be one of the main causes of influenza B virus epidemic in Liuzhou City.Influenza viruses are sensitive to the use of neuraminidase inhibitor anti-influenza drugs.
Influenza B virusWhole genomeGenetic characteristicsRecommended vaccine strain
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