黄土高原阿拉善黄鼠鼠疫疫源地鼠疫杆菌病原学特征

Etiological characteristics of Yersinia pestis in loess plateau plague natural foci of Citellus alaschanicus

目的了解甘宁黄土高原阿拉善黄鼠鼠疫疫源地鼠疫菌病原学及流行病学特征,为制定该地区鼠疫防控策略提供科学依据。方法对1962-1991年甘宁黄土高原阿拉善黄鼠鼠疫疫源地不同宿主体内分离的49株鼠疫杆菌(Yersinia pestis)进行生化试验、毒力因子鉴定(F1、VW、Pgm、PstI)、质粒分析和差异区段(DFR)分析;选取17株鼠疫菌进行小鼠毒力测定,计算最小致死量(MLD)。结果49株被试菌株中,甘肃会宁县和靖远县分离的18株鼠疫菌生态型为黄土高原B型,宁夏海原县、西吉县及固原县分离的31株鼠疫菌生态型为黄土高原A型。49株被试菌株均能产生F1和PstI,其中75.5%(37/49)的鼠疫菌具备4个毒力因子;17株代表性鼠疫菌的毒力测定结果显示,均为强毒菌。该疫源地鼠疫菌共携带3种质粒,Mr为6×10^(6)、45×10^(6)、65×10^(6),形成了一种稳定的质粒谱;DFR分型研究共发现10个基因组型,分别为1b型1株、7型1株、9型1株、11型1株、13型10株、17型4株、20型1株、26型16株、41型1株、43型1株,其主要基因组型为26型和13型。结论甘宁黄土高原阿拉善黄鼠鼠疫疫源地鼠疫菌生态型较为特殊,且毒力强,人类感染鼠疫后多为重症型,病死率高。因此,应加大该地区的鼠疫监测力度,严防动物鼠疫波及人间。

Objective To grasp the etiological and epidemiological characteristics of Yersinia pestis in Gan-Ning loess plateau plague natural foci of Citellus alaschanicus,and we provide scientific basis for making strategies of plague prevention and control in this area.Methods A total of 49 strains separated from different hosts in Gan-Ning plague foci from 1962 to 1991,and to do biochemical test,virulence factors evaluation(F1,PstI,VW,Pgm),plasmid analysis,different region genotyping(DFR),and we selected 17 strains to study the virulence to mice and calculate the minimum lethal dose(MLD).Results Totally 18 of the 49 strains were Loess Plateau B type,separated from Huining county and Jingyuan county in Gansu Province,31 strains were Loess Plateau A type,separated from Haiyuan,Xijie and Guyuan county in Ningxia Province.All the 49 strains could produce F1 and PST1,and 75.5%(37/49)of the strains had four virulence factors;17 strains were virulent strains in the virulence tests;All the strains carried 3 plasmids with molecular weights of 6×10^(6),45×10^(6),65×10^(6),and formed one stable plasmid profile;10 genotypes were found in DFR study,which were genomovar 1b(1 strain),genomovar 7(1 strain),genomovar 9(1 strain),genomovar 11(1 strain),genomovar 13(10 strains),genomovar 17(4 strains),genomovar 20(1 strain),genomovar 26(16 strains),genomovar 41(1 strain),genomovar 43(1 strain),and type 26 and 13 were main genotypes.Conclusions The strains separated from Gan-Ning plague foci have a special ecotype.It was virulent strain.Most of human infected with plague showed severe type and high fatality rate.Therefore,we should be increased monitoring efforts and prevent the animal plague spread to human beings.