2018 - 2019年云南省昭通市A型流感病毒基因特征分析

目的 分析2018 - 2019年云南省昭通市新甲型H1N1、H3N2亚型流感病毒流行情况及基因进化特征,为流感防控提供科学依据。方法 收集2018年1月 - 2019年10月昭通地区哨点医院流感样病例咽拭子标本2 863份进行real - time RT–PCR检测,用狗肾传代细胞( Madin - Darby canine kidney cell,MDCK)对核酸阳性样本进行病毒分离,分离得到的流感毒株采用血凝抑制实验进行鉴定分型。最终选取43株新甲型H1N1亚型流感毒株,及15株H3N2亚型毒株进行全基因组测序,使用MEGA 5.2软件进行序列分析。结果 系统发生分析表明95.35%(41 / 43)昭通新甲型H1N1分离株属于6B.1A支系, 93.33%(14/15)H3N2分离株属于3C.2a1b支系。与参考株A／California／07／2009相比,新甲H1N1分离株HA蛋白有7处抗原位点和1处受体结合位点发生变异,H3N2分离株有5处抗原位点和4处受体结合位点发生变异。结论 2018 - 2019年昭通地区流行的新甲型H1N1和H3N2亚型流感病毒毒株与WHO推荐的当年北半球的疫苗组分匹配,但H3N2亚型与WHO推荐的2019 - 2020年H3亚型疫苗株发生偏离,需加强监测。

Analysis on genetic characteristics of influenza A virus in Zhaotong city of Yunnan province from 2018 to 2019

The aim of this study was to analyze the epidemic situation and the phylogenetic characteristics of novel A/H1N1 and A/H3N2 influenza virus genes isolated in Zhaotong City of Yunnan Province from 2018 to 2019, so as to provide scientific basis for influenza prevention and control. Methods A total of 2863 faucial swabs collected among patients with an influenza-like illness(ILI) admitted to a sentinel surveillance hospitals of Zhaotong from January 2018 to October2019 were detected by real-time RT-PCR. The nucleic acid-positive specimens were cultured in Madin-Darby canine kidney(MDCK) cells to isolate virus, and the viral subtypes were identified by hemagglutination inhibition assay. 43 strains of novel A/H1N1 and 15 strains of A/H3N2 influenza strain were selected for high-throughput sequencing and the characteristics of HA gene were analyzed by MEGA5.2 software. Results The phylogenetic analysis showed that 95.35%(41/43) novel A/H1N1 influenza strains were grouped into genetic clade 6 B.1A, 93.33%(14/15) A/H3N2 strains were grouped into genetic clade 3 C.2 a1b.Compared with A/California/07/2009, novel A/H1N1 influenza strains had mutations at 7 antigentic sites and 1 receptor-binding sites(RBS), and the A/H3N2 strains had 5 antigentic sites and 4 RBS. Conclusion The circulating novel A/H1N1 and A/H3N2 influenza virus strains in Zhaotong city from 2017 to 2018 matched the under year vaccine component in the northern hemisphere recommended by the World Health Organization(WHO). However, it is significant to strengthen the monitoring of the A/H3N2 strains deviated from the H3N2 vaccine component recommended by WHO for 2019-2020.