云南省鼠疫疫源地中鼠疫噬菌体的分离、鉴定及其流行病学意义研究

Yersinia pestis phage has important significance of genetic evolution of Yersinia pestis and plague epidemic. Whether there are a lot of Yersinia pestis phages in Yunnan plague natural foci, what kind of those phages are, how the diversity they are, and how is the relationship between those phages and Yersinia pestis, moreover whether those phages relate with the recent rest of Yunnan plague. Four Yersinia pestis phages have been gotten from the natural foci in Yunnan province previously, and phenotype of these phages are different from diagnosis phage of Yersinia pestis. This study selects seven of natural plague foci in Yunnan, and intends to isolate Yersinia pestis phages from host animals, animals’ nests and indicator animals. Then systemic analysis will be measured of biological characteristics, genome and comparative genomics, proteomics, and so on. Through this study, on the one hand, we can give out phage distribution of epidemiological data in natural plague foci in Yunnan province. Moreover correlation analysis of these data can be done with plague surveillance data, so as to explore the relationship between phage distributions and plague epidemic. On the other hand, this study will get a certain number of Yersinia pestis phages, and phage library of Yersinia pestis was preliminarily constructed in Yunnan Province. Through a series of analysis of these phages, we can further understand the phage, which provides a basis to explore the co-evolution of phages and Yersinia pestis, provides reference for the study of plague epidemic law and reasonable inference of the relationship between the Yersinia pestis phage and the recent rest of Yunnan plague.

鼠疫噬菌体对鼠疫菌遗传进化以及鼠疫流行病学具有重要意义。云南鼠疫疫源地中是否广泛存在鼠疫噬菌体，是什么样的鼠疫噬菌体，其多样性如何，与云南鼠疫菌关系如何，又是否与云南近期鼠疫静息相关？本研究前期已从现场中分离到四株鼠疫噬菌体，初步鉴定其表型与鼠疫诊断噬菌体存在差异。本研究拟选取七个云南鼠疫疫源地区，从宿主动物、鼠巢及指示动物中大量分离鼠疫噬菌体，并对所分鼠疫噬菌体进行生物学特性、基因组及比较基因组、蛋白质组等相关分析。本项目的开展：一方面可获得云南省鼠疫疫源地内鼠疫噬菌体分布的流行病学数据，将这些数据结合鼠疫监测资料进行相关性分析，从而探索鼠疫噬菌体分布与鼠疫流行的关系；另一方面，将获得一定数量鼠疫噬菌体，初步构建云南省鼠疫噬菌体库，对其进行系列分析，可进一步认识鼠疫噬菌体，为其与鼠疫菌共进化提供依据，为探明鼠疫流行规律提供参考，为鼠疫噬菌体与云南鼠疫近期静息的相关性给出合理推断。

目的 查明云南鼠疫疫源地中是否广泛存在鼠疫噬菌体，是什么样的鼠疫噬菌体，进而探索鼠疫噬菌体分布与鼠疫流行的关系。方法 选择云南现行流行及历史疫源地进行调查，采集指示动物及宿主动物标本进行鼠疫噬菌体的分离。结果 从6933只宿主动物中，分离到276株鼠疫噬菌体（分离率为3.98%），从1737只犬中分离到164株鼠疫噬菌体（分离率为9.44%），犬中噬菌体的携带率显著高于宿主动物中的携带率（χ2=85.974，p<0.001）；28个调查点中，除禄劝县与瑞丽市外都分离到了鼠疫噬菌体；对其中182株鼠疫噬菌体进行电镜扫描，1株为短尾型的，181株为肌尾型，肌尾型中又可细分为3种类型：其中类似于λ噬菌体172株（占94.5%），类似于T4噬菌体6株（占3.3%），类似于P2噬菌体3株（占1.65%）。选取10株噬菌体进行了噬菌谱的测定，发现具有多宿主菌的特性；选取50余株噬菌体进行了基因组提取及测序工作，结果显示基因组大小不一从30-281kb，具有较丰富多态性。结论 鼠疫噬菌体广泛存在于云南省各个地区，现行流行地区与历史流行地区分离率未发现明显差异，指示动物中的携带率高于宿主动物，分离噬菌体无论表型还是基因型都具有多态性，本研究构建云南省鼠疫噬菌体库，为探明鼠疫流行与鼠疫噬菌体的相关性提供更多支撑。