河北省1例输入性登革热病例的病毒分离及其分子特征分析

Isolation and molecular characteristic analysis of dengue virus from an imported case of Hebei

目的从疑似登革热病例血清中分离病毒,获取全基因组数据并分析分子进化特征。方法采集河北省1例由柬埔寨输入的登革热疑似病例的血清样本,用胶体金法检测登革病毒IgM和IgG抗体以及NS1抗原;利用Vero E6细胞从血清中分离登革病毒,并采用Real-time PCR对病毒进行分型;扩增病毒全基因片段,将序列与国内外分离株序列进行比对,构建系统发生树。结果胶体金检测显示该病例血清登革病毒IgM、IgG抗体和NS1抗原均为阳性,从早期血清中分离到登革病毒,鉴定为I型登革病毒,分子进化分析揭示该分离株与东南亚地区毒株最为相似,病毒全基因组和E基因核苷酸序列同源性最高达99.99%,而与近年国内其他地区分离株进化关系较远。结论国内登革热的防控依旧需要加强输入性病例的监测。

Objective To isolate and identify dengue virus from serum sample of a suspected dengue fever case in Hebei,as well as obtain its whole genome sequence and analyze the molecular evolutionary characteristics.Methods The serum sample was collected to detect IgM and IgG antibody and NS1 antigen of dengue virus though colloidal gold method.Vero E6 cell line was used to isolate dengue virus from the patient’s early serum,and the subtype was identified by Real-time PCR.The viral whole genome fragment was amplified and sequenced,then compared it with reference sequences of viruses isolated from China and other countries,also compared with reference strains in the international epidemic area.The phylogenetic tree was constructed.Results Colloidal gold method test showed that the suspected dengue fever case was positive for IgM,IgG antibody and NS1 antigen.The virus isolated from the patient’s serum was identified as dengue virus type I,genomic molecular evolution analysis revealed the isolated strain was most similar with the strains in southeast Asia,and the nucleotide sequence similarity was more than 99.99%.Conclusion The surveillance of imported cases should be strengthened to prevent and control dengue fever epidemic.