2019年河南省一例输入性基孔肯雅热病例的发现与处置

目的诊断输入性疑似基孔肯雅热(CHIK)病例,处置输入性CHIK疫情,防止出现本地感染病例。方法2019年8月河南省新乡市辉县发生一起疑似输入性CHIK疫情。采用荧光定量反转录聚合酶链式反应、病毒分离方法检测病例、共同暴露者、接触者血清样本和蚊虫媒介样本,采用Clustal X和MEGA 7.0软件分析基孔肯雅病毒(CHIKV)E1基因序列;根据《基孔肯雅热预防控制技术指南(2012版)》开展流行病学调查、采取相应的预防控制措施。结果病例血清样本CHIKV核酸阳性、CHIKV分离阳性。分离株属于ECSA基因型,在E1基因区段与2017年中国浙江省输入株MG912993核苷酸/氨基酸同源性为100%,与河南省既往输入株MG925665核苷酸和氨基酸同源性分别为99.4%和99.8%。流行病学调查显示,病例共同暴露者1人、接触者3人,均无相应临床表现;以病例居住地为疫点进行媒介控制和蚊媒应急监测,疫点布雷图指数由首次监测的9.5降至第3次监测的3.2并一直维持在较低水平,蚊虫媒介CHIKV核酸阴性。结论河南省新乡市辉县输入性CHIK病例由ECSA基因型CHIKV导致,未引起本地疫情扩散。

Detection and management of an imported case of Chikungunya fever in Henan

ObjectiveTo understand the epidemiological and etiological characteristics of an imported Chikungunya fever case occurred in Huixian county of Henan province in August 2019 and provide evidence for the prevention and control of the further spread.MethodsThe serum samples of the case, person with co-exposure and contacts as well as mosquito samples were detected with real-time fluorescence quantitative RT-PCR and the virus isolation was conducted, E1 gene of the isolate was sequenced and analyzed by Clustal X and MEGA 7.0. Epidemiological investigation was conducted, and prevention and control measures were taken according to related technical guidelines.ResultsThe serum sample of the case was positive for nucleic acid of Chikungunya virus. The virus isolate (GenBank No. MN432879) belonged to ECSA genotype of Chikungunya virus. In E1 section, the isolate shared 100% nucleotide/amino acid homology of MN432879 with an imported strain (GenBank No. MG912993) in Zhejiang in 2017, and shared 99.4% nucleotide homology and 99.8% amino acid homology with an imported strain (GenBank No. MG925665) isolated in Henan. There was one case with co-exposure and three contacts, all of them showed no clinical manifestations of Chikungunya fever. The breteau index of the epidemic point declined from 9.5 in the first surveillance to 3.2 in the third surveillance and remained at a low level. Mosquito samples were negative for nucleic acid of Chikungunya virus.ConclusionThe imported Chikungunya fever case in Huixian county of Henan was caused by ECSA genotype Chikungunya virus, no further spread occurred in this area.