Genetic characteristics of influenza B virus Victoria lineage in Ma′anshan from 2019 to 2022
10.3760/cma.j.cn112309-20240426-00149
- VernacularTitle:马鞍山市2019—2022年乙型流感病毒Victoria亚型基因遗传特征分析
- Author:
Zikun YANG
1
;
Rong WANG
;
Zhibin SHEN
;
Xiaoyu JIANG
;
Xiaofang ZHU
;
Liangliang JIANG
Author Information
1. 马鞍山市疾病预防控制中心微生物检验科，马鞍山 243071
- Publication Type:Journal Article
- Keywords:
Influenza B virus;
Victoria lineage;
Genetic evolution;
Epidemiological characteristics
- From:
Chinese Journal of Microbiology and Immunology
2025;45(1):39-44
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze the genetic characteristics of influenza B virus Victoria lineage in Ma′anshan from 2019 to 2022.Methods:Throat swabs were collect from cases with influenza-like illness in three sentinel hospitals and from influenza outbreak events in Ma′anshan city from 2019 to 2022. Real-time fluorescence-based PCR was performed to detect the nucleic acids of influenza viruses in the swab samples. Statistical analysis was conducted using the influenza year as the detection cycle. MDCK cells and chicken embryos were used for virus isolation, and 31 strains of B/Victoria lineage were selected for whole-genome sequencing and genetic analysis.Results:A total of 11 258 throat swabs were collected from ILI cases, and 8.90% (1 002/11 258) of them tested positive for B/Victoria. Except for the period from the winter of 2020 to the spring of 2021, during which no epidemic outbreak of influenza was observed, there were peaks in the prevalence of B/Victoria influenza in winter and spring of the other years, with the positive rates ranging from 12.65% (54/427) to 46.68% (176/377) during peak seasons. Compared with the recommended vaccine strains, the homology of the HA gene nucleotides of the viral strains isolated from 2019 to 2022 ranged from 98.40% to 99.26%, and the homology of amino acids ranged from 96.21% to 98.80%. All isolated strains carried mutations in the 190-helix of the hemagglutinin protein; the strains isolated from 2019 to 2020 had two amino acid insertions at position 160-loop; and the strains isolated from 2021 and 2022 had mutations at positions 120-loop and 150-loop. No drug-resistant mutations were detected in the neuraminidase gene.Conclusions:The B/Victoria strains isolated in Ma′anshan city from 2019 to 2022 have key site variations as compared with the recommended vaccine strains, suggesting a decrease in vaccine immune efficacy. Therefore, it is necessary to strengthen the surveillance of viral mutations to provide reference for updating vaccine strains and formulating epidemic prevention and control measures.
