宁夏部分地区奶牛球虫感染情况调查与遗传进化分析

为了解宁夏地区奶牛球虫的感染现状与流行特征,以宁夏吴忠、石嘴山、贺兰地区5个不同规模化奶牛场采集的犊牛腹泻粪便样品为材料,利用饱和NaCl溶液飘浮法和麦克马斯特虫卵计数法观察统计球虫形态、种类与感染情况;并提取球虫卵囊基因组DNA,进行18S rRNA基因的扩增和测序,用DNAstar软件对奶牛球虫18S rRNA基因进行序列分析,并构建系统发育树。结果显示,在随机抽查的179份样品中,牛球虫病的平均感染率为56.98%,感染率的范围为40.00%~80.84%,平均每g粪便虫卵数(OPG)为1 358。孢子化卵囊呈圆形或椭圆形,初步确定该地区优势虫种为邱氏艾美尔球虫、牛艾美尔球虫,其大小为(25.7~36.0)μm×(21.4~27.1)μm。序列分析表明,宁夏地区所分离的虫株与其他虫株亲缘关系较远,但本地虫株之间有较近的亲缘关系。该研究丰富了奶牛球虫流行病学材料,也为该病的防治研究奠定了基础。

Infection investigation and genetic evolution analysis of dairy cow coccidiosis in parts of Ningxia

To investigate dairy cow coccidiosis infection status and epidemic characteristics in Ningxia, the fecal samples of calves with diarrhea collected from five large scale dairy farm in Wuzhong, Shizuishan and Helan of Ningxia were collected. The morphology, species and infection status of pathogeny were counted by saturated NaCl floating method and McMaster Egg Slide Counting method. Genomic DNA of coccidial oocyst was extracted for amplification and sequencing of 18S rRNA. DNAstar was used for sequence analysis with the published 18S rRNA gene of coccidia of dairy cattle, and a phylogenetic tree was constructed. Results showed that in the random of 179 samples, the average cow coccidiosis infection rate was 56.98%, the range of infection rate was 40.00%-80.84%, and average number of oocysts per gram feces (OPG) value was 1 358. Morphological observation showed that sporogenous oocysts were round or elliptic, and preliminarily demonstrated the dominant species in this area were Eimeria zuerni and Eimeria bovis, whose size were (25.7-36.0)μm×(21.4-27.1)μm. Sequence analysis showed that strains isolated from Ningxia had a distant relationship with other strains, but there was a close relationship between the local strains. This study not only enriched the epidemiological materials of dairy cow coccidiosis, but also laid a foundation for the prevention and treatment of the disease.