杭州市2018年-2020年登革热暴发疫情流行病学及病原特征分析

Analysis of epidemiologyical and molecular characteristics of the dengue outbreaks in Hangzhou,2018-2020

目的研究杭州市2018年—2020年登革热暴发疫情的流行病学及病原特征。方法应用RT-PCR方法检测血清标本中的登革病毒核酸及其型别,挑选11株代表性病毒株进行病毒分离、E基因扩增、序列测定及构建进化树,采用描述性流行病学方法分析2018年—2020年疫情流行病学特征。结果 2018年—2020共发生7起登革热暴发疫情,共报告45例本地病例,发生时间集中在2018年及2019年7月下旬—10月上旬,病例均为轻症,60%的病例年龄在50岁及以上。分离到登革病毒株44株,分型均为登革病毒Ⅰ型。11株代表性病毒E基因序列比对及进化分析,2018年分离病毒株与缅甸病毒株,2019年分离病毒株与菲律宾病毒株核苷酸序列一致性最高。结论 2018年—2020年杭州市本地暴发疫情由登革病毒Ⅰ型引起,传染源可能来自缅甸和菲律宾。

Objective To analyze the epidemiological and etiological characteristics of dengue fever outbreaks in Hangzhou,2018—2020.Methods Serum samples were collected from dengue fever cases for virus detecting and serotyping by RT-PCR. The envelope(E) gene was amplified and sequenced. Phylogenetic trees based on E gene sequence were then constructed and analyzed. Descriptive epidemiological method was used to analyze the epidemiological characteristics.Results There were7 outbreaks and 45 cases in 2018—2020, which mainly occurred in late July and early October. People above 50 years old accounted for 60% of cases with milder clinical symptom. A total of 44 dengue virus were isolated, which belonged to dengue virus type Ⅰ. The homologous and phylogenetic analysis showed that the isolates of 2018 had a closest phylogenetic relationship with dengue virus isolated from Myanmar and the isolates of 2019 had a closest phylogenetic relationship with dengue virus isolated from Philippines.Conclusion The outbreaks occurred in 2018—2020 caused by dengue virus type Ⅰ. The source of infection might be caused by imported dengue fever cases from Myanmar and Philippines.