一起肾综合征出血热聚集性疫情调查分析

Investigation and analysis of a clustered epidemic of hemorrhagic fever with renal syndrome

目的 调查肾综合征出血热(HFRS)疫情流行因素,提供防控依据。方法 现场调查对病例及其工作、生活区域并采用夹夜法捕捉鼠类,分类鉴定后无菌解剖取鼠肺、鼠血检测汉坦病毒(Hantaan virus, HV)携带情况;扩增测序病例及鼠类阳性标本中HV RNA提取物M片段进行同源性分析。结果 此次疫情共有病例4例,抗HV IgG和IgM均阳性,2份病例标本检测到HV RNA, 4份鼠标本检测到HV RNA,均为汉城病毒S3亚型,M基因片段100%同源,与山东的ZC12110、ZB8,北京的XiaotangshanRn7、 HaixingRn40亲缘关系最近,同源性均为98.8%;疫点地理环境、生活环境巨变,鼠类密度和鼠内HV病毒感染率高、携带HV鼠类分布范围广,人口密度大、生活环境差、职工与鼠类及其排泄物接触机会多。结论 本次疫情是由SEOV型汉坦病毒经褐家鼠向人传播引起;地理环境和生活环境的改变可使鼠类繁殖、活动等行为发生变化、人口密度大、无HFRS疫苗接种史、鼠类与人接触的机会多,均与本次疫情发生的相关。

Objective This paper aims to investigate the epidemic factors of hemorrhagic fever with renal syndrome(HFRS) and provide basis for its prevention and control. Methods On-site investigation of cases and their work and life was carried out, and rodents were captured by the clip-night method. After classification and identification, lungs and blood of the rats were aseptically dissected to detect the virus carrying status;HV RNA was extracted from amplified and sequenced cases and rodent-positive specimens. The homology analysis of the M fragment was carried out. Results There were 4 cases in this outbreak, and both anti-HV IgG and IgM were positive. HV RNA was detected in 2 cases of specimens, and HV RNA was detected in 4 mouse samples, all of which were Seoul virus S3 subtype, and the M gene segment was 100% homologous. It has the closest kinship with Shandong isolate ZC12110, ZB8 and Beijing isolate XiaotangshanRn7, HaixingRn40, and the M gene segment was 98.8% homologous. The geographical environment and living environment of the epidemic site have changed greatly. The density of rodents and the infection rate of HV virus in rats are high, the distribution of HV-carrying rodents is wide, the population density is large, the living environment is poor, and the workers have more chances to contact with rodents and their excreta. Conclusion This outbreak was caused by the transmission of SEOV type Hantaan virus to humans through R. norvegicus. Changes in geographical environment and living environment may lead to changes in breeding and activities of rodents. High population density, no HFRS vaccination history and more chances for rodents to come into contact with humans, all of which are related to the outbreak of this epidemic.