杭州市2019年登革病毒分子流行病学研究

Molecular epidemiological analysis of Dengue virus in Hangzhou,2019

目的了解2019年杭州市登革病毒分子特征和可能的传播来源。方法收集登革热患者血清样本,分析登革热流行特征。分别采用ELISA和RT-PCR方法检测登革热抗体、登革病毒核酸及其型别,再对核酸阳性样本进行E基因扩增、序列测定和进化分析。结果2019年杭州共检测登革热病例212例(输入性病例158例,本地病例54例),其中65例IgM抗体检测阳性,178例DENV通用型核酸检测阳性。输入性病例中4种血清型登革病毒均有检出,以DENV-1为主(占51.9%)。本地病例多由DENV-1基因I型(6/54)、IV型(26/54)和DENV-2 Cosmopolitan基因型(2/54)病毒引起,E基因序列分别与2019年广州和南昌流行株、2015年菲律宾株和2018年泰国株同源性较高。其中DENV-1基因IV型本地流行病毒的E基因序列高度同源,序列相似性高达99.9%~100%,推测为多起输入性病例引起的本地传播。结论受东南亚登革热疫情影响,杭州2019年登革热病例数量增幅明显,呈型别多样化、本地病例溯源复杂的特点,需进一步加强DENV分子特征研究。

To analyze the molecular characteristics and trace the origin of dengue virus in Hangzhou,2019.Serum samples and epidemiological characteristics were collected from dengue fever cases.Dengue antibodies tests,virus detecting and serotyping were performed by ELISA and RT-PCR,respectively.Phylogenetic trees based on E gene sequence of the dengue virus were then constructed and analyzed.A total of 212 positive samples(158 imported cases and 54 indigenous cases)were collected,among which 65 were positive for IgM,and 178 were positive for DENV RNA.All four serotypes of DENV were detected in imported cases,with a predominance of DENV-1 viruses,accounting for 51.9%of the cases.The indigenous DENV viruses belonged to DENV-1 genotype I,DENV-1 genotype IV,and DENV-2 Cosmopolitan genotype,and were respectively closely related to the strains from Guangzhou and Nanchang in 2019,Philippines in 2015,and Thailand in 2018.Indigenous DENV-1 genotype IV viruses had a high level of E gene sequence similarity(99.9%~100%homology),and their transmission may be caused by multiple imported cases.Affected by the massive dengue epidemic in Southeast Asian countries,an obvious increase in dengue fever cases was observed in Hangzhou in 2019,accompanied with diversifying serotypes detected and more complicated analysis in tracing origin.Further researches should be conducted to analyze the molecular characteristics of DENV.