2016-2018年江西省钩端螺旋体病鼠类动物流行病学调查与分离菌株鉴定

Epidemiological survey and identification of pathogenic Leptospira isolated from rats in Jiangxi Province during 2016-2018

目的初步了解江西省钩端螺旋体病主要宿主动物鼠类种类构成、带菌率及血清学和分子流行病学特征,为钩体病的防控提供科学依据。方法2016-2018年选取江西省钩体病4个国家级监测点上饶、上高、上犹及浮梁县作为现场监测地点,开展鼠类种类调查、钩体分离培养工作。利用暗视野显微镜凝集试验和MLST技术对分离菌株进行血清学鉴定和MLST基因分型。结果共计捕鼠14387只,平均鼠密度为9.76%,分离菌株64株,鼠类钩体分离率为4.56%。鼠种构成包括黑线姬鼠、褐家鼠、黄毛鼠、黄胸鼠及社鼠5个种类。4个监测点优势鼠种均以黑线姬鼠和黄毛鼠为主。血清群鉴定结果显示:64株菌株隶属于3个血清群,其中黄疸出血群为主要优势血清群,占81.25%,其次是爪哇群和致热群。MLST研究显示:64株菌株隶属于6个ST型别,分别为ST1、ST17、ST92、ST143、ST216和ST224,其中ST1为主要基因型,占76.56%。BioNumerics软件分析显示:64株菌株隶属于6个Clusters,分别对应6个ST型,血清学、MLST基因型分布具有明显地域差异。结论江西省以黑线姬鼠和黄毛鼠为优势鼠种,黄疸出血群和ST1为江西省钩体病主要流行型别,充分了解江西省钩体病可能的宿主动物以及血清学和分子流行病学特征,对钩体病的预防控制有一定的指导意义。

In order to investigate potential reservoir populations and the molecular and serological characterization of pathogenic Leptospira in China,a total of 1404 rodents belonging to 5 different species were trapped in four national monitoring sites of leptospirosis in Jiangxi during 2016-2018.The density of field rodent was 9.76%.The most prevalent rodent was Apodemus agrarius and Rattus rattoides in all the four sites in Jiangxi.A total of 64 Leptospira strains from 2 different species of field rodent were successfully isolated.The carriage rate in rats was 4.56%.Microscopic agglutination test(MAT)and multilocus sequence typing(MLST)were conducted in this study.A total of three serogroups were identified among 64 Leptospira strains.Serogroup Icterohaemorrhagiae was the most frequent serogroup,accounting for 81.25%,followed by Javanica and Pyrogenes.Six different sequence types(STs)including ST1,ST17,ST92,ST143,ST216 and ST224,were obtained By MLST.ST1 accounted for 76.56%and was the major genotype in Jiangxi Province in China.Phylogenetic analysis using BioNumerics softwares revealed that six major clusters(Cluster1 to Cluster6)corresponding to six ST types was identified among 64 isolates.Obvious epidemiological relationship was found between the distributions of serogroup,STs and isolated location.In this study,the results revealed that MLST analysis could be used to explore the genetic diversity and population structures of Leptospira.In this work,the results revealed that Apodemus agrarius and Rattus rattoides were the main animal reservoir,and Serogroup Icterohaemorrhagiae and ST1 were the major serogroup and genotype in Jiangxi Province,respectively.The potential reservoir populations and the detailed serological and molecular characteristics circulating in this region,may provide new insights into the epidemiology of leptospirosis in Jiangxi.