Evolutionary Ecology Group, Department of Biology, University of Antwerp, Wilrijk, Belgium.
Eco-Epidemiology Group, Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
Parasit Vectors. 2023 Mar 30;16(1):117. doi: 10.1186/s13071-023-05709-0.
The majority of the African population lives in rural areas where they heavily depend on crop and livestock production for their livelihoods. Given their socio-economic importance, we initiated a standardized multi-country (Benin, Burkina Faso, Ghana, Nigeria, Ethiopia Tanzania and Uganda) surveillance study to assess the current status of important tick-borne haemoparasites (TBHPs) of cattle.
We assessed pathogen prevalences (Anaplasma marginale, Anaplasma centrale, Babesia bigemina, Babesia bovis, Ehrlichia ruminantium, and Theileria parva) in the blood of 6447 animals spread over fourteen districts (two districts per country). In addition, we screened for intrinsic (sex, weight, body condition) and extrinsic (husbandry, tick exposure) risk factors as predictors of infections with TBHPs.
There was a large macro-geographic variation observed in A. marginale, B. bigemina, B. bovis and E. ruminantium prevalences. Most correlated with the co-occurrence of their specific sets of vector-competent ticks. Highest numbers of infected cattle were found in Ghana and Benin, and lowest in Burkina Faso. While T. parva was seldomly found (Uganda only: 3.0%), A. marginale was found in each country with a prevalence of at least 40%. Babesia bovis infected individuals had lower body condition scores. Age (as estimated via body weight) was higher in A. marginale infected cattle, but was negatively correlated with B. bigemina and E. ruminantium prevalences. Ehrlichia ruminantium infection was more often found in males, and A. marginale more often in transhumance farming. High levels of co-infection, especially the combination A. marginale × B. bigemina, were observed in all countries, except for Uganda and Burkina Faso. Babesia bigemina was more or less often observed than expected by chance, when cattle were also co-infected with E. ruminantium or A. marginale, respectively.
Tick-borne pathogens of cattle are ubiquitous in African's smallholder cattle production systems. Our standardized study will help a wide range of stakeholders to provide recommendations for TBHP surveillance and prevention in cattle, especially for B. bovis which heavily impacts production and continues its spread over the African continent via the invasive Rhipicephalus microplus tick.
大多数非洲人口居住在农村地区，他们的生计严重依赖农作物和牲畜生产。鉴于它们的社会经济重要性，我们启动了一项标准化的多国（贝宁、布基纳法索、加纳、尼日利亚、埃塞俄比亚、坦桑尼亚和乌干达）监测研究，以评估当前重要的蜱传血液寄生虫（TBHPs）的现状牛。
我们评估了 6447 头动物血液中的病原体流行率（边缘无浆体、中央无浆体、双芽巴贝斯虫、牛巴贝斯虫、牛埃立克体和小泰勒虫），这些动物分布在 14 个区（每个国家 2 个区）。此外，我们还筛查了内在（性别、体重、身体状况）和外在（畜牧业、蜱暴露）风险因素，作为感染 TBHPs 的预测因素。
观察到 A. marginale、B. bigemina、B. bovis 和 E. ruminantium 的流行率存在很大的宏观地理差异。与特定的媒介能力蜱的共同发生最相关。感染牛数量最多的国家是加纳和贝宁，而布基纳法索则最低。虽然 T. parva 很少见（仅在乌干达发现 3.0%），但在每个国家都发现了 A. marginale，其流行率至少为 40%。感染牛巴贝斯虫的个体身体状况评分较低。年龄（通过体重估计）在感染 A. marginale 的牛中较高，但与 B. bigemina 和 E. ruminantium 的流行率呈负相关。牛埃立克体感染更常见于雄性，而 A. marginale 更常见于游牧农业。除乌干达和布基纳法索外，所有国家均观察到高水平的合并感染，尤其是 A. marginale × B. bigemina 组合。当牛同时感染牛埃立克体或 A. marginale 时，观察到牛双芽巴贝斯虫的感染或多或少地高于预期的机会水平。
牛的蜱传病原体在非洲小农户牛生产系统中无处不在。我们的标准化研究将帮助广泛的利益相关者为牛的 TBHP 监测和预防提供建议，特别是对 B. bovis 的建议，它严重影响生产，并通过入侵的 Rhipicephalus microplus 蜱在非洲大陆继续传播。
