Etiological profile of influenza-like illness and genetic analysis of hemagglutinin and neuraminidase genes of influenza A（H3N2） viruses in Baotou during the 2022-2023 influenza season
10.3760/cma.j.cn112309-20250322-00093
- VernacularTitle:2022—2023监测年度包头市流感样病例病原学分布特征及甲型流感病毒H3N2血凝素与神经氨酸酶基因分析
- Author:
Xiaojuan CHEN
1
;
Yaoxing LIU
;
Rong JIN
;
Yaoxia KANG
;
Wei GAO
;
Li BO
;
Jingxian PENG
Author Information
1. 内蒙古包头市疾病预防控制中心微生物检验科，包头 014030
- Publication Type:Journal Article
- Keywords:
Influenza virus;
H3N2;
Amino acid variation;
Drug resistance site;
Genetic evolution
- From:
Chinese Journal of Microbiology and Immunology
2025;45(11):935-941
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the epidemiological characteristics of influenza-like illness（ILI）and the genetic evolutionary trends of the hemagglutinin（HA）and neuraminidase（NA）genes of influenza A（H3N2）viruses isolated in Baotou during the 2022-2023 influenza season.Methods:Etiological surveillance data for ILI cases in Baotou during the 2022-2023 influenza season were collected from the China Influenza Surveillance Information System. Descriptive statistical analysis was performed on the data. HA and NA genes of 30 influenza A（H3N2）viruses were sequenced. Amino acid variation sites，glycosylation sites，drug resistance genes，and phylogenetic trees were analyzed using MEGA 11 software and the NextClade online analysis tool.Results:A total of 1 443 ILI specimens were tested，of which 241（16.70%）were positive for influenza viruses. Among the positive cases，influenza A（H3N2）virus-positive cases accounted for 75.93%（183/241）. The nucleotide sequence similarity of the HA gene between the 30 influenza A（H3N2）isolates and the vaccine strains A/Hong Kong/2671/2019（H3N2），A/Cambodia/e0826260/2020（H3N2），and A/Darwin/9/2021（H3N2）ranged from 96.83% to 98.77%，while the amino acid sequence similarity ranged from 94.63% to 99.62%. A total of 14 amino acid variation sites and 11 conserved glycosylation sites were identified in the HA gene. For the NA gene，the nucleotide sequence similarity ranged from 98.37% to 99.65%，and the amino acid sequence similarity ranged from 94.64% to 98.28%. A total of three amino acid variation sites and nine conserved glycosylation sites were found in the NA gene. None of the 30 influenza A（H3N2）isolates had mutations associated with drug resistance，and all belonged to the clade 3C.2a1b.2a.2a.3a.1.Conclusions:During the 2022-2023 influenza season in Baotou，the circulating influenza A（H3N2）viruses belong to the same evolutionary clade as the 2021-2022 vaccine strain A/Cambodia/e0826360/2020（H3N2）. The isolates from different sources share a common evolutionary origin；however，variations are observed across the genome in terms of homology，molecular mutations，and glycosylation patterns.
