青海省祁连县鼠疫菌病原学分析及流行病学意义

The etiology and epidemiologicai significance o f Yersinia pestis in Qilian County, Qinghai Province

目的 探讨青海省祁连县鼠疫菌株生物学特点及流行病学意义，为该地区的鼠疫防治提供科学依据。方法 对1958 - 2011年青海省祁连县分离的67株鼠疫菌进行生化试验、毒力测定、毒力因子鉴定、质粒分析、鼠疫菌差异区段（different region，DFR）分型等研究。结果 根据生化指标，67株被试菌株中48株为青藏高原型，15株为祁连山型，其余4株与青海省疫源地生态型菌株均不相同；DFR分为8个基因组型，分别为8型（42株）、44型（15株）、5型（4株）、7型（2株）、19型（1株）、30型（1株）、32型（1株）、34型（1株）；95.52%（64／67）的被试菌株携带相对分子质量为6×10^6、45×10^6、52×10^6的质粒；85.07%（57／67）的鼠疫菌4个毒力因子俱全；96.00%（48／50）的鼠疫菌为强毒菌。结论 青海省祁连县分离的鼠疫菌具备青藏高原鼠疫病原体特性，鼠疫菌的毒力强，因此，要加大鼠疫监测力度和鼠疫防治知识宣传力度，严防动物间鼠疫波及人间。

Objective To investigate the biological characteristics and epidemiological significance of Yersinia pestis strains in Qilian County, Qinghai Province, in order to provide a scientific basis for plague prevention and control. Method Totally 67 strains were separated from kinds of host in Qilian County, Qinghai Province from 1958 to 2011, to do biochemical test, toxicity test, virulence factors evaluation, plasmid analysis and different region （DFR） genotyping. Results According to biochemical typing, 48 of the 50 strains tested were Qing-Tibet Plateau ecotype, 15 were Qilian Mountain ecotype, and the remaining 4 were different ecotypes from the plague foci in Qinghai plateau. The strains had 8 genomovars, and were given priority to genomovar8 （42 strains）, secondly, genomovar44 （15 strains）, genomovar5 （4 strains）, genomovar7 （2 strains）, genomovar19 （1 strain）, genomovar30 （1 strain）, genomovar32 （1 strain）, and genomovar34 （1 strain）. A proportion of 95.52% （64/67） of the strains contained 3 kinds of plasmid-6 × 106, 45 × 106, and 52 × 106; 85.07% （57/67） contained all the four virulence factors, and 96.00% （48/50） were velogenic strains. Conclusion The strains separated in Qilian County, Qinghai Province have the characteristics of Qinghai-Tibet Plateau plague＇s pathogen and have strong toxicity, so we should enhance the plague monitoring and give more publicity to plague prevention to prevent animal plague spreading to human.