2019-2020年湖南省鼠类携带汉坦病毒情况调查及其基因特征研究

Investigation of hantavirus carried by rats and its genetic characteristics study in Hunan province from 2019 to 2020

目的探究湖南省5个省级肾综合征出血热(HFRS)监测点鼠类携带汉坦病毒情况及病毒的遗传进化特征,为HFRS的科学防控提供参考依据。方法2019-2020年采用夹夜法分别在湖南省5个省级HFRS监测点(宁乡市、浏阳市、炎陵县、邵东市、双峰县)捕鼠并分离鼠肺样品,采用Real-time PCR技术开展病原检测,据此对毒株进行分型和基因测序,通过序列分析和构建系统发生树等方式解析汉坦病毒的遗传进化特征。结果不同监测点均仅检出了一种汉坦病毒毒株,阳性率分别为双峰县(15.24%)>宁乡市(5.13%)>浏阳市(4.17%)>邵东市(3.09%)>炎陵县(2.00%);汉滩型病毒(HTNV)和汉城型病毒(SEOV)的宿主分别为褐家鼠和黑线姬鼠,且前者(6.83%)的检出率远高于后者(1.86%);不同监测点HTNV的大(L)、中(M)、小(S)基因片段和编码区长度一致,各分离株之间M基因的序列一致性为96%~100%,与参比株M基因的序列一致性为88%~98%;不同SEOV的各基因片段长度及编码氨基酸数量也无差异,各分离株之间及其与参比株M基因的序列一致性分别为93%~100%和83%~97%。结论湖南省鼠类主要携带HTNV和SEOV两种型别汉坦病毒毒株,虽然已发生一定程度遗传变异,但当前未监测到“宿主转换”现象,推测鼠类宿主中汉坦病毒大规模流行的风险较低。

Objective To investigate the carriage of hantavirus(HV)by rodents at 5 provincial-level hemorrhagic fever with renal syndrome(HFRS)surveillance sites in Hunan province,as well as the genetic evolution characteristics of the virus,thereby providing a reference for the scientific prevention and control of HFRS.Methods Between 2019 and 2020,rodents were captured using the night-clip method at 5 provincial-level HFRS surveillance sites in Hunan province(Ningxiang city,Liuyang city,Yanling county,Shaodong city,and Shuangfeng county).Mouse lung samples were collected and tested for pathogens using real-time PCR technology.Based on these tests,virus strains were typed and sequenced.Genetic evolution characteristics of hantavirus were analyzed through sequence analysis and the construction of phylogenetic trees.Results Only one type of HV strain was detected at each monitoring site,and the positive rates were as follows:Shuangfeng county(15.24%)>Ningxiang city(5.13%)>Liuyang city(4.17%)>Shaodong city(3.09%)>Yanling county(2.00%);the hosts of hantaan virus(HTNV)and seoul virus(SEOV)were Rattus norvegicus and Apodemus agrarius,respectively,and the infection rate of the former(6.83%)was much higher than that of the latter(1.86%);the length of large(L),medium(M),small(S)gene fragments and coding region of HTNV at different monitoring sites were consistent;the sequence consistency of M gene was 96%-100%among the isolates and 88%-98%with reference strains;there was no difference in the length of each gene segment and the number of encoded amino acids among different SEOV,and the homology of M gene between each isolates and reference strains was 93%-100%and 83%-97%,respectively.Conclusion Rodents in Hunan province mainly carried HV strains of HTNV and SEOV;although genetic variation had occurred to a certain extent,no“host switching”phenomenon had been detected,which suggested that the risk of large-scale HV epidemics in rodent hosts was relatively low.