Adjou Moumouni Paul Franck, Guo Huanping, Gao Yang, Liu Mingming, Ringo Aaron Edmond, Galon Eloiza May, Vudriko Patrick, Umemiya-Shirafuji Rika, Inoue Noboru, Suzuki Hiroshi, Xuan Xuenan
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-855, Japan; Research Center for Global Agromedicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-855, Japan.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-855, Japan.
Vet Parasitol Reg Stud Reports. 2018 Dec;14:137-143. doi: 10.1016/j.vprsr.2018.10.006. Epub 2018 Oct 29.
In many African countries including Benin, the reluctance of some livestock owners to blood collection from their cattle makes epidemiological surveys cumbersome and prevents regular monitoring of tick-borne diseases. In the present study, Amblyomma variegatum ticks were used to find out more about bovine tick-borne pathogens. DNA extracts from 910 adult ticks collected off cattle in North East Benin were examined for Babesia bigemina, B. bovis, Theileria taurotragi, T. annulata, T. orientalis, T. parva, T. mutans, Anaplasma marginale and Ehrlichia ruminantium using pathogen-specific PCR assays and sequence analyses. Altogether, 21.6% of the ticks carried at least one pathogen. A. marginale (142/910) was the most frequent pathogen, followed by E. ruminantium (57/910), B. bovis (10/910), T. mutans (3/910) and B. bigemina (1/910). Theileria taurotragi, T. annulata, T. orientalis, T. parva were not detected in the samples. Babesia bigemina, B. bovis and T. mutans were present in only one location whereas A. marginale and E. ruminantium were found in ticks from 7/8 locations surveyed. Coinfections occurred in 7.1% of all positive ticks. The analyses of partial sequences of B. bovis spherical body protein 4, B. bigemina rhoptry-associated protein-1a, T. mutans 18S rRNA and A. marginale major surface protein 5 showed high sequence conservation and homologies between Benin isolates and those from other African countries. However, E. ruminantium pCS20 partial sequences were different from published West African isolates and presented similar genetic variation with South and East African isolates. These results provide information on the pathogens circulating in North East Benin and suggest that Am. variegatum, one of the most abundant ticks in Africa, may play a role in the transmission of A. marginale.
在包括贝宁在内的许多非洲国家，一些牲畜养殖户不愿让自家的牛采血，这使得流行病学调查变得繁琐，也妨碍了对蜱传疾病的定期监测。在本研究中，使用了变异革蜱来进一步了解牛蜱传病原体。利用病原体特异性PCR检测和序列分析，对从贝宁东北部牛身上采集的910只成年蜱的DNA提取物进行了检测，以查找双芽巴贝斯虫、牛巴贝斯虫、泰勒虫、环形泰勒虫、东方泰勒虫、小泰勒虫、突变泰勒虫、边缘无形体和反刍兽埃立克体。总体而言，21.6%的蜱携带至少一种病原体。边缘无形体（142/910）是最常见的病原体，其次是反刍兽埃立克体（57/910）、牛巴贝斯虫（10/910）、突变泰勒虫（3/910）和双芽巴贝斯虫（1/910）。样本中未检测到泰勒虫、环形泰勒虫、东方泰勒虫、小泰勒虫。双芽巴贝斯虫、牛巴贝斯虫和突变泰勒虫仅在一个地点被发现，而边缘无形体和反刍兽埃立克体在8个调查地点中的7个地点的蜱中被发现。7.1%的所有阳性蜱发生了混合感染。对牛巴贝斯虫球形蛋白4、双芽巴贝斯虫棒状体相关蛋白-1a、突变泰勒虫18S rRNA和边缘无形体主要表面蛋白5的部分序列分析表明，贝宁分离株与其他非洲国家的分离株之间具有高度的序列保守性和同源性。然而，反刍兽埃立克体pCS20部分序列与已发表的西非分离株不同，与南非和东非分离株呈现出相似的遗传变异。这些结果提供了关于贝宁东北部流行的病原体的信息，并表明变异革蜱作为非洲最常见的蜱之一，可能在边缘无形体的传播中发挥作用。
