中文摘要：

目的分离合肥地区奶牛源隐孢子虫,并鉴定其种类。方法采集安徽省合肥市某奶牛场285头成年母牛粪样,采用饱和蔗糖溶液漂浮法和改良抗酸染色法检测牛粪中隐孢子虫卵囊,并分离纯化隐孢子虫阳性粪样中的卵囊,抽提其基因组DNA作为模板,根据隐孢子虫18S rRNA和HSP70基因设计引物,用PCR和巢式PCR方法扩增目的片段,对巢式PCR产物进行克隆、测序,并运用DNAStar软件对序列进行同源性比对,构建系统进化树。结果两种方法检测均为阳性的粪样有5份,感染率为1.8%（5/285）。隐孢子虫卵囊呈椭圆或卵圆形,饱和蔗糖溶液漂浮法分离的隐孢子虫卵囊大小为7.37μm×6.13μm,形状指数（长/宽）为1.20;改良抗酸染色法检获的隐孢子虫卵囊大小为7.58μm×6.20μm,形状指数为1.22。巢式PCR扩增出的18S rRNA和HSP70基因片段分别为250 bp和325 bp。合肥奶牛源隐孢子虫5株分离株18S rRNA基因与安氏隐孢子虫（Cryptosporidium andersoni）DQ989573序列一致性最高,两者在系统进化树上为同一分支。这5株分离株的HSP70基因序列与安氏隐孢子虫AY954892和DQ989576序列一致性最高,且在系统进化树上为同一分支。结论合肥市某奶牛场分离的奶牛源隐孢子虫为安氏隐孢子虫。

英文摘要：

Objective To isolate cow-origin Cryptosporidium in Hefei,and identify its species.Methods 285 dairy cattle fecal samples collected from a farm in Hefei were examined by using floating saturated solution of sucrose and modified acid-fast staining.Cryptosporidium oocysts were isolated and purified from positive fecal samples.Genetic DNA was extracted to be the template.According to the sequence of 18S rRNA gene and HSP70 gene from Cryptosporidium sp.,the primers were designed and synthesized.The PCR products were amplified by PCR and nested-PCR.The nested PCR products were cloned and sequenced.Homology searches and phylogenic tree construction were done by DNAStar software.Results Five fecal samples were positive by morphological methods with an infection rate of 1.8%（5/285）.Oocysts from the 5 positive fecal samples were elliptical or ovoid detected by using floating saturated solution of sucrose and modified acid-fast staining with the size of 7.37 μm×6.13 μm and 7.58 μm×6.20 μm,and a shape index of 1.20 and 1.22,respectively.Nested-PCR resulted in a 18S rRNA and HSP70 gene fragments with approximately 250 bp and 325 bp,respectively.The five isolates showed a high level of nucleic acid identity with sequence data of the 18S rRNA gene of Cryptosporidium andersoni（DQ989573）,and they were clustered in the same clade.The highest HSP70 gene sequence identity was found among the five isolates and other reported C.andersoni isolates（AY954892 and DQ989576）,and they were placed into the same clade.Conclusion The cow-origin Cryptosporidium isolates derived from Hefei is Cryptosporidium andersoni.