中文摘要：

目的 为了解进口奶牛寄生的隐孢子虫对引种场污染情况及是否影响隐孢子虫种类和基因型在当地的分布。方法 采用PCR方法检测河南省某规模化引种场奶牛隐孢子虫感染情况。结果 基于18SrRNA基因位点进行PCR检测,奶牛隐孢子虫总感染率为17.8%（90/507）,鉴定出4种隐孢子虫,分别为微小隐孢子虫、牛隐孢子虫、芮氏隐孢子虫和安氏隐孢子虫,隐孢子虫感染率随牛年龄增长而呈递减趋势,差异有统计学意义（P〈0.01）。断奶前犊牛以微小隐孢子虫为优势感染种,断奶前犊牛腹泻与微小隐孢子虫感染呈正相关性,差异有统计学意义（P〈0.01）。基于gp60基因位点,43份微小隐孢子虫阳性样品成功扩增出35份,序列分析显示35个微小隐孢子虫均为人兽共患基因亚型IIdA19G1,而奶牛引种地（澳大利亚）的牛源微小隐孢子虫均为IIa亚型家族存在显著不同。结论 证实微小隐孢子虫为犊牛腹泻病原之一,IId亚型为中国独特分布的微小隐孢子虫亚型,其基因亚型存在地理隔离遗传特征,引种青年牛和成年牛不影响当地重要人兽共患虫种微小隐孢子虫基因亚型分布,从这个角度考虑不具有生物安全重要性。

英文摘要：

We investigated the effect of Cryptosporidium from imported cow in the local area and the distribution effect of Cryptoaporidium species and genotypes in the local area. Using polymerase chain reaction （PCR）, we studied the infection of Cryptosporidium from dairy cattle in an imported farm in Henan Province. The overall infection rate of Cryptosporidium in dairy cattle was 17.8% （90/507） based on 18SRNA gene locus. Cryptosporidium parvum, Cryptosporidium boris, Crypto- sporidiurn ryanae and Cryptosporidium andersoni were found. Significant differences were observed between the infection rate of sampling and age （P〈0.01）. The infection rate of Cryptosporidium decreased with age increasing in dairy cattle. Crypto- sporidium parvum were the dominating Cryptosporidium spp. in pre-weaning calves. We found a positively correlation be- tween the infection of Cryptosporidium and diarrhea of pre-weaning calves （P~0.01）. Thirty-five Cryptosporidium parvum were successfully amplified from 43 positive samples at gp60 gene locus, the subtype of the amplified Cryptosporidium par- rum were IIdA19G1, the subtype was different with IIa subtype which were found in imported country （Australia）. This study confirmed that Cryptosporidium parvum is a kind of diarrhea pathogens in dairy calves, the subtype of Cryptosporidium par- rum in China is only lid and the subtype of Cryptosporidium parvum exist geographical isolation genetic characteristics. It does not have the importance of biological safety from the point that imported heifers and adults do not affect the distribution of Cryptosporidium species and genotypes in the local area.