中国嘉兴甲型H1N1流感病毒大流行后时期的遗传特征分析

Genetic characteristics analysis of influenza A(H1N1) virus in Jiaxing, China, in the postepidemic era.

作者信息

Song Yin, Zhang Xue, Ji Jimei, Li Lina, Zhou Yamei, Ren Ganglin, Lv Shencong, Zhang Xiaofei, Yan Yong, Zhu Guoying

机构信息

Jiaxing Key Laboratory of Pathogenic Microbiology, Jiaxing Center for Disease Control and Prevention, No. 486, Wenqiao Road, Jiaxing, 314050, China.

Tongxiang Center for Disease Control and Prevention, No. 1238, Wenhua Road, Tongxiang, 314500, China.

出版信息

BMC Infect Dis. 2025 Jul 10;25(1):905. doi: 10.1186/s12879-025-11257-y.

DOI:10.1186/s12879-025-11257-y

PMID:40640732

Abstract

BACKGROUND

Following the lifting of COVID-19 pandemic control measures, a progressive increase in influenza A virus activity, particularly the H1N1 subtype, has been observed in Jiaxing. This study systematically characterized the genomic evolution of influenza A(H1N1) viruses circulating in Jiaxing, China during the 2023-2024 epidemic seasons through whole-genome sequencing and phylogenetic analysis.

METHODS

Viral RNA was detected by quantitative real-time PCR (qPCR) and 83 influenza A(H1N1) isolates (48 from 2023 and 35 from 2024 surveillance) were selected for whole-genome sequencing. Launch RDP4, MEGA11 and iTOL were used to analyze the homology, molecular evolutionary clusters and resistance sites of influenza A(H1N1) virus.

RESULTS

The positivity rates of influenza A(H1N1) virus in Jiaxing were 10.66% in 2023 and 5.09% in 2024, respectively. Compared with vaccine strain A/Wisconsin/67/2022, the influenza A(H1N1) virus in 2023 and 2024 showed high homology, with the nucleotide homology of hemagglutinin gene ranging from 97.9% to 99.2% and that of neuraminidase gene ranging from 98.3% to 99.1%. Among 83 Jiaxing strains, 80 were classified as clade 6B.1A.5a.2a and 3 were assigned to clade 6B.1A.15a.2a.1. These strains were further categorized into subclades C.1 (45), C.1.9(17), C.1.9.3 (18), and D (3). Additionally, an HA/NA reassortant strain (A/ZJNH/SWL1331/2023) was identified in 2023, followed by an oseltamivir-resistant strain (A/ZJPH/SWL1544/2024) carrying the H275Y substitution in 2024. A total of 31 amino acid substitutions were identified in the HA1 segment of Jiaxing influenza A(H1N1) strains, affecting three antigenic sites: Ca (S137P, A139D, A141T/V, R142K, D222G), Cb (L70F, S71F), and Sb (I185S, D187N, S190G), plus an additional Ca1 substitution (K169Q).

CONCLUSIONS

During 2023-2024, multiple genomic sites of influenza A(H1N1) viruses in Jiaxing have acquired mutations, underscoring the need for enhanced continuous surveillance and prevention of H1N1 influenza.

摘要

背景

自新型冠状病毒肺炎疫情防控措施解除后，嘉兴市甲型流感病毒活动呈逐步上升趋势，尤其是H1N1亚型。本研究通过全基因组测序和系统发育分析，对2023 - 2024流行季在中国嘉兴市传播的甲型H1N1流感病毒的基因组进化进行了系统表征。

方法

采用实时荧光定量聚合酶链反应（qPCR）检测病毒RNA，并选取83株甲型H1N1流感病毒分离株（2023年48株，2024年监测35株）进行全基因组测序。利用RDP4、MEGA11和iTOL分析甲型H1N1流感病毒的同源性、分子进化聚类和耐药位点。

结果

嘉兴市2023年和2024年甲型H1N1流感病毒阳性率分别为10.66%和5.09%。与疫苗株A/威斯康星/67/2022相比，2023年和2024年的甲型H1N1流感病毒具有较高同源性，血凝素基因核苷酸同源性为97.9%至99.2%，神经氨酸酶基因核苷酸同源性为98.3%至99.1%。在83株嘉兴毒株中，80株被归类为6B.1A.5a.2a分支，3株被归类为6B.1A.15a.2a.1分支。这些毒株进一步分为C.1（45株）、C.1.9（17株）、C.1.9.3（18株）和D（3株）亚分支。此外，2023年鉴定出1株HA/NA重配株（A/浙江NH/ SWL1331/2023），2024年鉴定出1株携带H275Y替换的耐奥司他韦毒株（A/浙江PH/ SWL1544/2024）。在嘉兴甲型H1N1流感毒株的HA1片段中共鉴定出31个氨基酸替换，影响3个抗原位点：Ca（S137P、A139D、A141T/V、R142K、D222G）、Cb（L70F、S71F）和Sb（I185S、D187N、S190G），外加1个Ca1替换（K169Q）。