Department of Zoology, Abdul Wali Khan University, Mardan, 23200, Pakistan.
Institute of Biotechnology and Genetic Engineering, The University of Agriculture, Peshawar, 25130, Pakistan.
Vet Parasitol. 2020 Mar;279:109044. doi: 10.1016/j.vetpar.2020.109044. Epub 2020 Jan 31.
Ticks and tick-borne pathogens are one of the major threats to livestock production worldwide. The aim of present study is to specify the molecular epidemiology and its associated risk factors of two well-distributed tick-borne pathogens Anaplasma marginale and Theileria annulata in cattle population from North-western Pakistan. Blood samples were Collected from 60 (32.6 %) local breed cattle, 101 (54.9 %) from crossbreed, and 24 (13.0 %) from exotic breed with total of 184 blood samples. Species-specific PCR assays were performed to detect the presence of A. marginale and T. annulata based on 16S rRNA and 18S rRNA genetic makers respectively. PCR results showed that A. marginale was 16.3 % prevalent and T. annulata was 29.9 % prevalent in the study area with a total prevalence rate of 46.2 % (85/184) of the tested blood samples. District wise analysis revealed that both pathogens were highly prevalent in district Dir Upper (13.6 %) and least prevalent in district Chitral (10.3 %). Univariable analysis of risk factors showed that only breed and acaricidal treatment were significant determinants (P < 0.05) for A. marginale infection, however, in case of T. annulata infection; breed, age, gender, grazing practice, and acaricidal treatment were potential determinants (P < 0.05). Multivariable analysis specified that breed and acaricidal treatment were considered as significant risk factors for A. marginale infection (P < 0.05) whereas acaricidal treatment was found to be a significant determinant for T. annulata infection (P < 0.05). Phylogenetic analysis indicated that A. marginale 16S rRNA and T. annulata 18S rRNA isolates showed similarities and shared phylogeny with same isolates reported from Asia. This is the first molecular report on the epidemiology and risk factors analysis of A. marginale and T. annulata infections in cattle population from NW Pakistan. Further large scale study is required to investigate molecular, epidemiological and genotypic aspects as well as potential risk factors analysis from the country to facilitate designing strategies to control tick-borne pathogen and reduce losses to cattle industry.
蜱虫和蜱传病原体是全球畜牧业的主要威胁之一。本研究旨在明确分布广泛的两种蜱传病原体——边缘无浆体（Anaplasma marginale）和环形泰勒虫（Theileria annulata）在巴基斯坦西北部牛群中的分子流行病学及其相关风险因素。从当地品种牛中采集了 60 份（32.6%）、杂交品种牛 101 份（54.9%）和外来品种牛 24 份（13.0%）的血液样本，总计采集了 184 份血液样本。基于 16S rRNA 和 18S rRNA 遗传标记，采用种特异性 PCR 检测方法检测 A. marginale 和 T. annulata 的存在。PCR 结果显示，在研究区域内，A. marginale 的流行率为 16.3%，T. annulata 的流行率为 29.9%，总流行率为 46.2%（85/184）。按地区分析显示，两种病原体在迪尔上区（Dir Upper）高度流行（13.6%），而在奇特拉尔区（Chitral）最低（10.3%）。单变量风险因素分析表明，仅品种和杀蜱剂处理是 A. marginale 感染的重要决定因素（P<0.05），而在 T. annulata 感染的情况下，品种、年龄、性别、放牧实践和杀蜱剂处理是潜在决定因素（P<0.05）。多变量分析表明，品种和杀蜱剂处理被认为是 A. marginale 感染的重要风险因素（P<0.05），而杀蜱剂处理是 T. annulata 感染的重要决定因素（P<0.05）。系统发育分析表明，A. marginale 16S rRNA 和 T. annulata 18S rRNA 分离株与亚洲报道的相同分离株具有相似性和共同的系统发育关系。这是首次对巴基斯坦西北部牛群中 A. marginale 和 T. annulata 感染的流行病学和风险因素进行的分子报告。需要进一步进行大规模研究，以调查该国的分子、流行病学和基因型方面以及潜在风险因素分析，为控制蜱传病原体和减少对养牛业的损失提供策略。
