Pienaar Ronel, Latif Abdalla A, Thekisoe Oriel M M, Mans Ben J
Parasites, Vectors and Vector-Borne Diseases, Agricultural Research Council-Onderstepoort Veterinary Institute, Onderstepoort 0110, South Africa.
Parasitology Research Programme, Department of Zoology and Entomology, University of the Free State Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866, South Africa.
Parasitology. 2014 Mar;141(3):411-24. doi: 10.1017/S0031182013001728. Epub 2013 Nov 7.
Strict control measures apply to movement of buffalo in South Africa including testing for Theileria parva, the causative agent of Corridor disease in cattle. The official test is a real-time hybridization PCR assay that amplifies the 18S rRNA V4 hyper-variable region of T. parva, T. sp. (buffalo) and T. sp. (bougasvlei). Mixed infections with the latter organisms affect diagnostic sensitivity due to PCR suppression. While the incidence of mixed infections in the Corridor disease endemic region of South Africa is significant, little information is available on the specific distribution and prevalence of T. sp. (buffalo) and T. sp. (bougasvlei). Specific real-time PCR assays were developed and a total of 1211 samples known to harbour these parasites were screened. Both parasites are widely distributed in southern Africa and the incidence of mixed infections with T. parva within the endemic region is similar (∼25-50%). However, a significant discrepancy exists in regard to mixed infections of T. sp. (buffalo) and T. sp. (bougasvlei) (∼10%). Evidence for speciation between T. sp. (buffalo) and T. sp. (bougasvlei) is supported by phylogenetic analysis of the COI gene, and their designation as different species. This suggests mutual exclusion of parasites and the possibility of hybrid sterility in cases of mixed infections.
南非对水牛的流动实施严格的管控措施，包括检测牛泰勒虫，它是牛走廊病的病原体。官方检测采用实时杂交PCR检测法，该方法可扩增牛泰勒虫、泰勒虫（水牛）和泰勒虫（布加斯弗莱）的18S rRNA V4高变区。由于PCR抑制作用，与后两种生物的混合感染会影响诊断敏感性。虽然在南非走廊病流行地区混合感染的发生率很高，但关于泰勒虫（水牛）和泰勒虫（布加斯弗莱）的具体分布和流行情况的信息却很少。研究人员开发了特异性实时PCR检测方法，并对总共1211份已知携带这些寄生虫的样本进行了筛查。这两种寄生虫在南部非洲广泛分布，在流行地区与牛泰勒虫的混合感染发生率相似（约25%-50%）。然而，泰勒虫（水牛）和泰勒虫（布加斯弗莱）的混合感染情况存在显著差异（约10%）。对细胞色素氧化酶亚基I（COI）基因的系统发育分析支持了泰勒虫（水牛）和泰勒虫（布加斯弗莱）之间的物种形成证据，以及它们作为不同物种的分类。这表明寄生虫之间相互排斥，并且在混合感染的情况下可能存在杂交不育的情况。
