摘要
目的 对一起聚集性疫情中的间日疟原虫样本进行基因分型和分子溯源分析,为病例来源的判定提供参考依据.方法 收集2018年6-7月湖南省隆回县一起间日疟聚集性疫情中4例患者的血样进行实时荧光定量PCR(quantitative real-time PCR,qPCR)虫种鉴定,并采用9个微卫星分子标记对4个样本的虫株进行基因分型,基于亚太地区消除疟疾网络间日疟原虫微卫星基因型数据库(VivaxGEN-MS)对不同国家和地区的间日疟原虫株进行种群遗传学STRUCTURE分析,判定虫株所属的遗传亚群和地理来源.结果 经qPCR鉴定,4个病例均为间日疟原虫感染,4个病例样本的9个微卫星位点均成功分型,4个样本的基因单体型不同,其中病例1、病例3和病例4为单一克隆虫株感染,病例2为多克隆虫株感染.用STURCTURE分析把所有间日疟原虫样本分成2个遗传亚群(K=2)时,4例湖南样本被划分为热带株遗传亚群(来源于埃塞尔比亚、伊朗、不丹、马来西亚、印度尼西亚和中国南部的虫株);用STURCTURE分析把所有间日疟原虫样本分成4个遗传亚群(K=4)时,4例湖南样本被划分为南亚/东南亚株遗传亚群(来源于不丹、马来西亚、印度尼西亚和中国南部的虫株).结论 分子溯源分析结果不支持该起疫情中4例间日疟原虫株的感染来源为中国中部种群,疟原虫分子溯源技术可为疟疾消除和消除后疟疾病例感染来源的判定提供客观证据.
Abstract
Objective To conduct genotyping and molecular tracing analysis on Plasmodium vivax samples from a cluster of P.vivax malaria outbreak in order to provide a reference for case geographical origin determination.Methods Blood samples from 4 patients in a vivax malaria cluster in Longhui County,Hunan Province from June to July 2018 were collected for species identification by qPCR,and 9 microsatellite molecular markers were used to genotype the parasite strains from four samples.The population genetic STRUCTURE analysis was performed based on the VivaxGEN-MS microsatellite genotype database of P.vivax in the Asia Pacific Malaria Elimination Network,to determine the genetic subgroups and geographical origin of the strains.Results By qPCR,all 4 cases were identified as Plasmodium vivax infection,and 9 microsatellite loci of the 4 cases were successfully typed,and the four samples had different genetic haplotypes,among which case 1,case 3,and case 4 were infected by a single clonal strain,and case 2 was infected by a polyclonal strain.When all P.vivax samples were divided into 2 subpopulations(K=2)by STURCTURE analysis,4 Hunan samples were classified into tropical genetic subpopulations(comprising strains from Ethiopia,Iran,Bhutan,Malaysia,Indonesia,and southern China).When the samples were divided into 4 subgroups by STURCTURE analysis(K=4),the 4 Hunan samples were classified as South Asian/Southeast Asian genetic subgroups(originating from Bhutan,Malaysia,Indonesia,and southern China).Conclusions The results of molecular tracing do not support that the 4 P.vivax strains in this outbreak originated from the population of central China.The technology of molecular tracing of P.vivax can provide objective evidence for determining the source of infection in malaria cases during the stage of malaria elimination and post-elimination.
基金项目
江苏省卫生健康委医学科研项目(M2020090)
江苏省科教能力提升工程项目(ZDXYS202207)
NETL
NSTL
万方数据