2014-2019年揭阳市登革病毒E基因序列分析

Sequence analysis of E gene of dengue virus isolated in Jieyang,2014-2019

目的探讨揭阳市登革病毒(DENV)的分子特征并进行生物学溯源。方法收集2014-2019年揭阳市登革热流行期间登革热疑似和临床诊断病例的急性期血清,用实时荧光定量RT-PCR方法检测病毒核酸及分型,阳性标本进行病毒分离及鉴定,扩增并测定部分分离株E基因序列,用生物学软件进行序列比对分析并构建系统进化树。结果896份急性期血清中DENV核酸阳性556份,阳性率为62.05%;血清型以DENV-Ⅰ为主(534例,占96.04%),其次为DENV-Ⅱ(18例,占3.24%)。序列分析显示,DENV-Ⅰ分离株基因型分属Ⅰ型和Ⅴ型,以Ⅰ型为主;DENV-Ⅱ分离株基因型均属于Cosmopolitan型。DENV-Ⅰ、DENV-Ⅱ分离株与周边地市、珠三角城市及东南亚国家流行株同源性较高。DENV-Ⅰ、DENV-Ⅱ分离株均属于弱毒株。结论2014-2019年揭阳市登革病毒以血清Ⅰ型基因Ⅰ型为主,其次是血清Ⅱ型基因Cosmopolitan型;推测揭阳市登革热流行毒株多来源于周边地市、珠三角城市及东南亚国家。

Objective To investigate the molecular characteristics of dengue virus and trace its biological origin in Jieyang.Methods Acute phase serum samples of suspected and clinically diagnosed cases of dengue fever were collected during the dengue epidemic in Jieyang from 2014 to 2019.The nucleic acid and typing of dengue virus were detected by using real-time fluorescence quantitative RT-PCR.The positive specimens were isolated and identified.The E gene sequences of some virus isolates were amplified and determined.The E gene was sequenced and phylogenetic relationship was analyzed by using the bioinformatics software.Results Among the 896 cases,556 were positive for DENV nucleic acid;the positive rate was 62.05%;among which,96.04% were DENV-Ⅰ and 3.24% were DENV-Ⅱ.Sequence analysis showed that DENV-Ⅰ isolates were type Ⅰ and Ⅴ genotypes,mainly type Ⅰ;DENV-Ⅱ isolates were Cosmopolitan genotype.DENV-Ⅰ and DENV-Ⅱ strains had high homology with the surrounding cities,the Pearl River delta cities and the Southeast Asian countries.DENV-Ⅰ and DENV-Ⅱ isolates belonged to weak strains.Conclusions The dengue virus isolates from Jieyang during 2014-2019 were mainly DENV-Ⅰ and DENV-Ⅱ.DENV-Ⅰ isolates were type Ⅰ and Ⅴ genotypes while DENV-Ⅱ isolates were Cosmopolitan genotype.It was speculated that the dengue epidemic strains in Jieyang were mainly from the surrounding cities,the Pearl River delta cities and the Southeast Asian countries.