云南省2例人感染欧亚类禽H1N1猪流感病毒分子特征分析

Molecular characteristics of the Eurasian avian H1N1 swine influenza viruses isolated from two infected patients in Yunnan province of China

目的 回顾性分析云南省2例人感染欧亚类禽H1N1猪流感病毒(Eurasian avian-like H1N1 swine influenza viruses,EAH1N1 SIVs)分子特征及遗传进化特征,为流行性感冒(流感)防控提供科学依据。方法 对2015年云南省流感监测网络实验室从流感样病例标本中分离到的2株EAH1N1 SIVs毒株进行全基因组测序,使用DNAStar、MEGA6.0等软件进行分子特征分析和系统进化树构建。结果 云南省2015年2例人感染欧亚类禽H1N1猪流感病毒株EAH1N1 SIVs A/Yunnan-Wuhua/SWL1869/2015(H1N1)和A/Yunnan-Longyang/SWL1982/2015(H1N1)均与湖南株A/Hunan/42443/2015同源性较高,同源性分别为97.6%~99.1%和97.9%~99.4%,是EAH1N1 SIVs与A(H1N1)pdm09重配病毒,为G5基因型。受体结合位点分析表明,2株病毒结合α-2,6半乳糖苷唾液酸人受体,为低致病性流感病毒。糖基化位点分析结果显示,2株病毒在HA上有7个潜在的糖基化位点,可能影响与疫苗株抗原的匹配性。耐药性分析表明2株病毒对神经氨酸酶抑制剂药物敏感,但对烷胺类药物耐药。结论 EAH1N1 SIVs对人类健康威胁较大,加强流感监测工作,密切追踪流感病毒的变异情况,能及早发现EAH1N1 SIVs及其他致病性和传播力增强的流感病毒。

Objective To analyze the molecular and genetic evolutionary characteristics of the Eurasian avian H1 N1 swine influenza viruses(EAH1 N1 SIVs) isolated from two infected patients in Yunnan province of China.Methods Whole genome sequencing was done for the two EAH1 N1 SIVs strains isolated from influenza-like case specimens in Yunnan Provincial Influenza Surveillance Network Laboratory in 2015,then the DNAStar and MEGA 6.0 and other software were used to analyze the molecular features and construct phylogenetic tree.Results Two cases of human infections with EAH1 N1 SIVs A/Yunnan-Wuhua/SWL1869/2015(H1 N1) and A/Yunnan-Longyang/SWL1982/2015(H1 N1) in Yunnan province in 2015 were both related to Hunan strain A/Hunan/42443/2015 with high homology,ranging from 97.6%—99.1% and 97.9%—99.4%,respectively.It is a reassorted virus between EAH1 N1 SIVs and A(H1 N1)pdm09 which was G5 genotype.Receptor binding site analysis showed that the two virus strains bound to the α-2,6 galactosylsialic acid human receptor and were low pathogenic influenza viruses.The results of glycosylation site analysis showed that there were seven potential glycosylation sites on HA of the two strains that might affect the antigen matching of the vaccine strains.Drug resistance analysis showed that the two viruses were sensitive to neuraminidase inhibitors,but resistant to alkylamines. Conclusions EAH1N1SIVs pose a great threat to human health.Strengthening influenza monitoring and closely tracking the variation of influenza virus can quickly detect EAH1N1SIVs and other influenza viruses with enhanced pathogenicity and transmission.