十二指肠贾第虫是重要的人兽共患原虫，家畜是人体感染该虫的重要传染源。研究表明，我国牛源十二指肠贾第虫呈现遗传多样性和地理隔离特征。新疆具有相对封闭的内陆水循环区系，家畜养殖量大，共用草场和水源，申请人课题组前期研究发现，该地区牛源十二指肠贾第虫集聚体E亚型存在遗传多样性，其他家畜是否也存在宿主适应性和地理隔离分化特征尚不清楚。本项目拟以新疆地区家畜为主要研究对象，采用单基因位分型技术分离鉴定十二指肠贾第虫集聚体A、B和E分离株，利用多位点序列分型计算其遗传多态性、重组频率、连锁不平衡以及不同宿主间遗传差异程度，重点解析新疆不同地区和不同宿主源十二指肠贾第虫A、B和E分离株群体遗传结构和宿主适应遗传特征。研究结果对于阐明十二指肠贾第虫人兽共患传播机制具有直接意义。

Giardia duodenalis（G.duodenalis）is an important protozoon for human-beast infection, and livestock is an important source of human infection. Studies have shown that G. duodenalis in China has some features such as genetic diversity and geographical isolation. Xinjiang has a relatively closed inland water cycle system, and the number of livestock is large, thus pastures and water sources are shared. Previous study of applicant’s research group find that there exists genetic diversity in E subtype of G.duodenalis from ox in the region. It’s unclear that whether other livestock present features of host adaptation and geographical isolation differentiation. Therefore, this project attempts to use livestock in Xinjiang as main research object, with single genotyping technology to isolate and identify A, B and E isolates of G.duodenalis agglomerate. And this project uses Multilocus Sequence Typing （MLST） to calculate genetic polymorphism, recombination frequency, linkage disequilibrium and degree of genetic differences among different hosts, focusing on the analysis of genetic structure and host adaptation of A, B and E isolates of G.duodenalis from different regions and host sources in Xinjiang. Research results will be of great significance for elucidating G.duodenalis transmission mechanism for human-beast infection.