Omondi David, Masiga Daniel K, Fielding Burtram C, Kariuki Edward, Ajamma Yvonne Ukamaka, Mwamuye Micky M, Ouso Daniel O, Villinger Jandouwe
International Centre of Insect Physiology and Ecology (icipe), Nairobi, Kenya.
University of Western Cape, Bellville, South Africa.
Front Vet Sci. 2017 Jun 1;4:73. doi: 10.3389/fvets.2017.00073. eCollection 2017.
Although diverse tick-borne pathogens (TBPs) are endemic to East Africa, with recognized impact on human and livestock health, their diversity and specific interactions with tick and vertebrate host species remain poorly understood in the region. In particular, the role of reptiles in TBP epidemiology remains unknown, despite having been implicated with TBPs of livestock among exported tortoises and lizards. Understanding TBP ecologies, and the potential role of common reptiles, is critical for the development of targeted transmission control strategies for these neglected tropical disease agents. During the wet months (April-May; October-December) of 2012-2013, we surveyed TBP diversity among 4,126 ticks parasitizing livestock and reptiles at homesteads along the shores and islands of Lake Baringo and Lake Victoria in Kenya, regions endemic to diverse neglected tick-borne diseases. After morphological identification of 13 distinct , and tick species, ticks were pooled (≤8 individuals) by species, host, sampling site, and collection date into 585 tick pools. By supplementing previously established molecular assays for TBP detection with high-resolution melting analysis of PCR products before sequencing, we identified high frequencies of potential disease agents of ehrlichiosis (12.48% , 9.06% ), anaplasmosis (6.32% , 14.36% , and 3.08% ,), and rickettsiosis (6.15% , 2.22% , 4.27% , and 4.95% spp.), as well as sp. and apicomplexan hemoparasites (0.51% sp., 2.56% , and 1.37% ) among tick pools. Notably, we identified in both and pools of ticks sampled from livestock in both study areas as well as in (66.7%) and (100%) sampled from tortoises and (63.6%) sampled in both cattle and tortoises at Lake Baringo. Similarly, we identified in rhipicephaline ticks sampled from livestock and dogs in both regions and (75%) sampled from monitor lizards at Lake Victoria. These novel tick-host-pathogen interactions have implications on the risk of disease transmission to humans and domestic animals and highlight the complexity of TBP ecologies, which may include reptiles as reservoir species, in sub-Saharan Africa.
尽管多种蜱传病原体(TBP)在东非地区呈地方性流行,对人类和牲畜健康有公认的影响,但该地区对其多样性以及与蜱和脊椎动物宿主物种的具体相互作用仍知之甚少。特别是,尽管在出口的陆龟和蜥蜴中发现爬行动物与牲畜的蜱传病原体有关联,但爬行动物在蜱传病原体流行病学中的作用仍然未知。了解蜱传病原体生态学以及常见爬行动物的潜在作用,对于制定针对这些被忽视的热带病病原体的有针对性的传播控制策略至关重要。在2012 - 2013年的雨季(4 - 5月;10 - 12月),我们在肯尼亚巴林戈湖和维多利亚湖沿岸及岛屿的家园中,对寄生于牲畜和爬行动物的4126只蜱进行了蜱传病原体多样性调查,这些地区是多种被忽视的蜱传疾病的地方性流行区。在对13种不同的硬蜱和软蜱物种进行形态学鉴定后,按物种、宿主、采样地点和采集日期将蜱(≤8只个体)合并为585个蜱样本池。通过在测序前对PCR产物进行高分辨率熔解分析来补充先前建立的用于蜱传病原体检测的分子检测方法,我们在蜱样本池中发现了较高频率的埃立克体病潜在病原体(12.48%,9.06%)、无形体病病原体(6.32%,14.36%,3.08%)、立克次体病病原体(6.15%,2.22%,4.27%,4.95% spp.),以及巴贝斯虫属物种和顶复门血寄生虫(0.51% sp.,2.56%,1.37%)。值得注意的是,我们在两个研究区域从牲畜采集的蜱样本池以及从陆龟采集的蜱样本池(66.7%)和在巴林戈湖从牛和陆龟采集的蜱样本池(63.6%)中均检测到了 。同样,我们在两个区域从牲畜和狗采集的璃眼蜱样本以及在维多利亚湖从巨蜥采集的蜱样本(75%)中检测到了 。这些新发现的蜱 - 宿主 - 病原体相互作用对疾病传播给人类和家畜的风险具有影响,并突出了蜱传病原体生态学的复杂性,在撒哈拉以南非洲,其生态学可能包括将爬行动物作为储存宿主物种。