2021-2022年度海南省B型Victoria系流感病毒病原学特征分析

Genetic variability of circulating influenza B victoria viruses in Hainan,2021−2022

目的了解2021—2022监测年度海南省B型Victoria系流感病毒的流行状况,分析其抗原性、耐药性和基因变异情况。方法选取33株B型Victoria系流感病毒,利用标准雪貂抗血清进行抗原性分析和荧光法检测病毒对神经氨酸酶抑制剂(NAI)的敏感性,应用Illumina公司MiSeqDx深度测序平台进行基因组序列测定,使用MEGA 10.1.8和DNAStar 7.0.1生物信息学软件进行多序列比对和分析,并采用邻位归并法(N-J)绘制系统进化树。结果2021—2022监测年度海南省流感病毒基因型为B型Victoria系,依据WHO命名方式,33株分离株血凝素(HA)基因和神经氨酸酶(NA)基因均属于1A.3遗传分支,未发生HA与NA基因分支间的重配,与WHO推荐的疫苗株B/Washington/02/2019(2020—2022)抗原性类似,对磷酸奥司他韦敏感,检测到1株NA基因发生D197E氨基酸位点变异并对扎那米韦的敏感性高度降低的毒株。结论2021—2022监测年度海南省流行的B型Victoria系流感病毒与疫苗株相匹配,对神经氨酸酶抑制剂类药物敏感。

Objective In order to understand the prevalence of influenza B virus,the antigenic,resistance to antiviral medications,and genetic characteristics of influenza B viruses circulating in Hainan province during 2021−2022 were analyzed.Methods The antigenic charactetistics of 33 influenza B Victoria lineage viruses were analyzed with reference ferret anti-sera and were tested for neuraminidase inhibitors using a phenotypic assay.The genome of influenza B Victoria lineage viruses were sequenced using the MiSeq™platform(Illumina).Multi-sequence alignment analyses were undertaken using MEGA 10.1.8 and DNAStar 7.0.1.A phylogenetic tree was constructed with the neighbor-joining method.Results The result showed the B Victoria lineage viruses were prevalent in Hainan Province during 2021−2022.The hemagglutinin(HA)and neuraminidase(NA)gene sequences from Hainan circulating viruses were grouped in clade 1A.3,reassortant between HA and NA was not identified.The isolated viruses were antigenically closely related to the recommend vaccine strain B/Washington/02/2019(2020−2022).All 33 viruses were sensitive to Oseltamivir;one viruse had highly reduced sensitivity to Zanamivir with the mutation sites of D197E.Conclusions Overall,the predominant circulating B Victoria lineage viruses in Hainan province during 2021−2022 were matched by current influenza vaccine and have retained susceptibility to neuraminidase inhibitors.