First detection of Theileria parva in cattle from Cameroon in the absence of the main tick vector Rhipicephalus appendiculatus
First detection of Theileria parva in cattle from Cameroon in the absence of the main tick vector Rhipicephalus appendiculatus
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DOI：
10.1111/tbed.13425
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发表时间：
2020-03-01
影响因子：
4.3
通讯作者：
Pelle, Roger
中科院分区：
文献类型：
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作者：
Silatsa, Barberine A.;Simo, Gustave;Pelle, Roger
牲畜疾病及其病媒传播的一个主要风险因素是用于贸易和放牧的活体动物不受控制的跨境移动。这种移动限制了对蜱传播病原体的有效控制，包括小泰勒虫。在包括喀麦隆在内的中非国家，只进行了有限的研究来确定影响牛的蜱和蜱传疾病。我们在此报告收集T.通过2016年进行的一项全国横断面调查，在喀麦隆进行了一项关于小母牛的研究，该调查涉及从该国五个农业生态区（AEZ）的63个地点收集牛的血液样本。对479份随机抽取的样本进行了基于ELISA的感染牛监测，发现了T。parva占22.7%; 41.1%的牛存在变异。对1,340份代表性DNA样本进行T. parva使用基于p104抗原基因的巢式PCR检测鉴定出25例（1.86%）阳性。阳性牛分布在I、II、III和V农业生态区。p104阳性牛均未表现出东海岸热（ECF）的临床症状。用反向线性杂交法（RLB）检测，分别有58份（4.3%）和1,139份（85%）与T. parva和T.变异寡核苷酸探针。这是T. parva from Cameroon.令人惊讶的是，没有扇头蜱蜱，T。在一项平行研究中，对该国现有的蜱类进行了全面的形态学和分子调查，确定了小蜱。在25头p104阳性牛中，只有两头牛的CD 8 + T细胞靶抗原表达的抗原基因Tp 1呈PCR阳性。Tp 1扩增子的克隆和测序显示与参考T. parva Muguga.这一新发现引起了对ECF可能蔓延到中非地区的严重关切。
A major risk factor for the spread of livestock diseases and their vectors is the uncontrolled transboundary movement of live animals for trade and grazing. Such movements constrain effective control of tick-transmitted pathogens, including Theileria parva. Only limited studies have been undertaken to identify ticks and tick-borne diseases (TTBDs) affecting cattle in central African countries, including Cameroon. We hereby report the collection of baseline data on the prevalence of T. parva in Cameroon through a countrywide cross-sectional survey, conducted in 2016, involving collection of blood samples from cattle from 63 sites across the five agro-ecological zones (AEZs) of the country. ELISA-based surveillance of infected cattle was performed on 479 randomly selected samples and revealed specific antibodies to T. parva in 22.7% and T. mutans in 41.1% of cattle. Screening of 1,340 representative DNA samples for the presence of T. parva identified 25 (1.86%) positives using a p104 antigen gene-based nested PCR assay. The positives were distributed across agro-ecological zones I, II, III and V. None of the p104 positive cattle exhibited clinical symptoms of East Coast fever (ECF). Using reverse line blot (RLB), 58 (4.3%) and 1,139 (85%) of the samples reacted with the T. parva and T. mutans oligonucleotide probes, respectively. This represents the first report of T. parva from Cameroon. Surprisingly, no Rhipicephalus appendiculatus ticks, the main vector of T. parva, were identified in a parallel study involving comprehensive morphological and molecular survey of tick species present in the country. Only two of the 25 p104 positive cattle were PCR-positive for the CD8+ T-cell target schizont-expressed antigen gene Tp1. Cloning and sequencing of Tp1 amplicons revealed sequence identity with the reference T. parva Muguga. This new finding raises serious concerns of a potential spread of ECF into the central African region.