青海高原鼠疫病原生态学研究

The pathogenic ecology research on plague in Qinghai plateau

目的 分析青海高原鼠疫病原生态学特征.方法 以青海省内1954-2012年不同地区、宿主、媒介体内分离的952株鼠疫菌作为研究对象,采用分子生物学技术与常规技术及地理信息系统（GIS）对其进行表型特征、质粒谱、基因组分型、宿主及媒介感染谱等分析,并从病原生态学角度对青海高原鼠疫病原学特征、地理分布、主要宿主、主要媒介等方面特征进行了探讨.结果 青海高原鼠疫菌的生态型为青藏高原型占91.49％ （871/952）、祁连山型占6.41％（61/952）、青海田鼠型占1.26％（12/952）.83.6％（796/952）的鼠疫菌4种毒力因子检测均为阳性（荚膜抗原、鼠疫杆菌素Ⅰ、毒力抗原因子、色素沉着因子）,93.26％（367/392）的鼠疫菌毒力检测结果显示为强毒菌.725株分离自青海高原鼠疫自然疫源地的鼠疫菌共携带有9种质粒,其中喜马拉雅旱獭鼠疫疫源地分离的713株菌包含9种质粒,相对分子质量（Mr）分别为6×106、7 ×106、23×106、27×106、30×106、45×106、52 × 106、65×106和92×106.青海田鼠鼠疫疫源地的12株菌只携带3种质粒,Mr分别为6×106、45×106、65×106.携带大质粒（Mr分别为52×106、65 × 106和92×106）的鼠疫菌独自规律地分布在特定的地理位置,具有分类属性.青海高原两类鼠疫自然疫源地的841株菌株共发现有11个基因型,其中喜马拉雅旱獭鼠疫疫源地以5、8型为主,共611株,8型菌株占56.00％（471/841）,5型菌株占23.07％（194/841）;还发现了3个新的基因型,即新1（62株）、新2（52株）、新3（48株）型;青海高原青海田鼠鼠疫疫源地12株鼠疫菌基因型为14型.结论 青海疫源地内主要宿主和传播媒介直接影响鼠疫流行的空间分布规律及病原体特征,且鼠疫生态地理景观多态性导致了鼠疫菌基因型的复杂性.

Objective To study the pathogenic ecology characteristics of plague in Qinghai plateau. Methods Applied molecular biology techniques, conventional technologies and geographic information system （GIS） to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc. of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012. Results The ecotypes of these strains were Qingzang plateau （91.49% ,871/952） ,Qilian mountain （6. 41% ,61/952） and Microtusfuscus （ 1.26%, 12/952）. 83.6% （796/952） of these strains contained all the 4 virulence factors （ Frl, Pesticinl, Virulence antigen,and Pigmentation）,93.26% （367/392） were velogenic strains confirmed by virulence test. 725 Yersinia pestis strains were separated from Qinghai plateau plague loci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid,the Mr were 6 × 106 ,7 × 106 ,23 ×106 ,27 × 106 ,30× 106 ,45× 106 ,52 ×106 ,65 × 106 and 92 × 106 respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6 ×106 , 45 × 106 ,65 × 106. Meanwhile,the strains carring large plasmid （52× 106 ,65 × 106 and 92 × 106） were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague loci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague loci were given wiority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% （471/841）, genomovar 5 accounted for 23.07% （ 194/841 ）. Besides, 3 new genomovars, including new 1 （ 62 strains） , new 2 （ 52 strains） , new 3 （48 strains） were newly founded, and 12 strains of Microtusfuscus plague foci were genomovar 14. Conclusion The main host and media of Qinghai plateau plague ibci directly affected the spatial distribution regularities of plague epidemic and the pathogens characteristics, meanwhile the polymorphism of plague ecological geographic landscape leds to the complexity of Yersinia pestis＇ genotype.