International Centre of Insect Physiology and Ecology (icipe), P.O Box 30772-00100, Nairobi, Kenya.
Department of Zoology and Entomology, University of Pretoria, Private Bag 20, Pretoria, 0028, South Africa.
BMC Vet Res. 2021 Nov 27;17(1):363. doi: 10.1186/s12917-021-03074-7.
Tick-borne pathogens (TBPs) are of global importance, especially in sub-Saharan Africa where they represent a major constraint to livestock production. Their association with human disease is also increasingly recognized, signalling their zoonotic importance. It is therefore crucial to investigate TBPs prevalence in livestock populations and the factors associated with their presence. We set out to identify TBPs present in cattle and to determine associated risk factors in western Kenya, where smallholder livestock production is important for subsistence and market-driven income.
Tick-borne pathogen infections in blood samples collected from cattle at livestock markets and slaughterhouses between May 2017 and January 2019 were identified by high-resolution melting analysis and sequencing of PCR products of genus-specific primers. Of the 422 cattle sampled, 30.1% (127/422) were infected with at least one TBP, while 8.8% (37/422) had dual infections. Anaplasma spp. (19.7%) were the most prevalent, followed by Theileria (12.3%), Ehrlichia (6.6%), and Babesia (0.2%) spp. Sequence analysis of the TBPs revealed them to be Anaplasma platys-like organisms (13.5%), Theileria velifera (7.4%), Anaplasma marginale (4.9%), Theileria mutans (3.1%), Theileria parva (1.6%), and Babesia bigemina (0.2%). Ehrlichia ruminantium, Rickettsia spp., and arboviruses were not detected. Exotic breeds of cattle were more likely to be infected with A. marginale compared to local breeds (OR: 7.99, 95% CI: 3.04-22.02, p < 0.001). Presence of ticks was a significant predictor for Anaplasma spp. (OR: 2.18, 95% CI: 1.32-3.69, p = 0.003) and Ehrlichia spp. (OR: 2.79, 95% CI: 1.22-7.23, p = 0.022) infection. Cattle sampled at slaughterhouses were more likely to be positive for Anaplasma spp. (OR: 1.64, 95% CI: 1.01-2.70, p = 0.048) and A. marginale (OR: 3.84, 95% CI: 1.43-12.21, p = 0.012), compared to those sampled at livestock markets.
This study reports TBP prevalence and associated risk factors in western Kenya, factors which are key to informing surveillance and control measures.
蜱传病原体（TBPs）具有全球重要性，尤其是在撒哈拉以南非洲地区，它们对畜牧业生产构成了重大制约。人们越来越认识到它们与人类疾病的关联，表明它们具有动物源性。因此，调查牲畜种群中 TBPs 的流行情况以及与它们存在相关的因素至关重要。我们旨在确定肯尼亚西部存在于牛群中的蜱传病原体，并确定相关的风险因素，因为在肯尼亚西部，小农户畜牧业对生计和市场驱动的收入很重要。
2017 年 5 月至 2019 年 1 月期间，在牲畜市场和屠宰场采集的牛血液样本中，通过高分辨率熔解分析和属特异性引物 PCR 产物的测序来确定蜱传病原体感染情况。在 422 头采样牛中，30.1%（127/422）至少感染了一种 TBP，而 8.8%（37/422）存在双重感染。阿氏普氏菌（19.7%）最为普遍，其次是泰勒虫（12.3%）、埃立克体（6.6%）和巴贝虫（0.2%）。对 TBPs 的序列分析表明，它们是阿氏普氏菌样生物体（13.5%）、泰勒虫弗氏体（7.4%）、边缘阿氏普氏菌（4.9%）、突变泰勒虫（3.1%）、小泰勒虫（1.6%）和双芽巴贝斯虫（0.2%）。未检测到无形体、立克次体和虫媒病毒。与本地品种相比，外来品种的牛更有可能感染边缘阿氏普氏菌（OR：7.99，95%CI：3.04-22.02，p<0.001）。有蜱的存在是阿氏普氏菌（OR：2.18，95%CI：1.32-3.69，p=0.003）和无形体（OR：2.79，95%CI：1.22-7.23，p=0.022）感染的重要预测因子。与在牲畜市场采样的牛相比，在屠宰场采样的牛更有可能对阿氏普氏菌呈阳性（OR：1.64，95%CI：1.01-2.70，p=0.048）和边缘阿氏普氏菌（OR：3.84，95%CI：1.43-12.21，p=0.012）。
本研究报告了肯尼亚西部的蜱传病原体流行情况和相关风险因素，这些因素是为监测和控制措施提供信息的关键。
