Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium.
Biology Department, Arba Minch University, Arba Minch, Ethiopia.
PLoS Negl Trop Dis. 2020 Mar 20;14(3):e0007947. doi: 10.1371/journal.pntd.0007947. eCollection 2020 Mar.
Cutaneous leishmaniasis (CL) is a major public health concern in Ethiopia. However, knowledge about the complex zoonotic transmission cycle is limited, hampering implementation of control strategies. We explored the feeding behavior and activity of the vector (Phlebotomus pedifer) and studied the role of livestock in CL transmission in southwestern Ethiopia.
Blood meal origins of engorged sand flies were determined by sequencing host DNA. A host choice experiment was performed to assess the feeding preference of P. pedifer when humans and hyraxes are equally accessible. Ear and nose biopsies from livestock were screened for the presence of Leishmania parasites. Sand flies were captured indoor and outdoor with human landing catches and CDC light traps to determine at which time and where P. pedifer is mostly active.
A total of 180 P. pedifer sand flies were found to bite hosts of 12 genera. Humans were the predominant blood meal source indoors (65.9%, p < 0.001), while no significant differences were determined outdoors and in caves. In caves, hyraxes were represented in blood meals equally as humans (45.5% and 42.4%, respectively), but the host choice experiment revealed that sand flies have a significant preference for feeding on hyraxes (p = 0.009). Only a single goat nose biopsy from 412 animal samples was found with Leishmania RNA. We found that P. pedifer is predominantly endophagic (p = 0.003), but occurs both indoors and outdoors. A substantial number of sand flies was active in the early evening, which increased over time reaching its maximum around midnight.
In contrast to earlier suggestions of exclusive zoonotic Leishmania transmission, we propose that there is also human-to-human transmission of CL in southwestern Ethiopia. Livestock does not play a role in CL transmission and combined indoor and outdoor vector control measures at night are required for efficient vector control.
皮肤利什曼病（CL）是埃塞俄比亚的一个主要公共卫生问题。然而，由于对复杂的人畜共患病传播周期知之甚少，这阻碍了控制策略的实施。我们探索了（Phlebotomus pedifer）的吸血行为和活动，并研究了家畜在埃塞俄比亚西南部 CL 传播中的作用。
通过测序宿主 DNA 确定饱血沙蝇的血液来源。当人类和蹄兔同样容易接触时，进行了一项宿主选择实验，以评估 P. pedifer 的摄食偏好。对家畜的耳和鼻活检进行筛查，以确定是否存在利什曼原虫寄生虫。通过人诱捕和 CDC 诱捕器在室内和室外捕获沙蝇，以确定 P. pedifer 最活跃的时间和地点。
总共发现 180 只 P. pedifer 沙蝇叮咬了 12 个属的宿主。人类是室内主要的血液来源（65.9%，p<0.001），而室外和洞穴中则没有显著差异。在洞穴中，蹄兔与人类的血液摄入量相等（分别为 45.5%和 42.4%），但宿主选择实验表明沙蝇对捕食蹄兔有明显的偏好（p=0.009）。在 412 个动物样本中，只有一只山羊鼻活检发现有 Leishmania RNA。我们发现 P. pedifer 主要是内食性的（p=0.003），但同时存在于室内和室外。傍晚时分有大量的沙蝇活跃，随着时间的推移，沙蝇的数量逐渐增加，午夜时分达到最大值。
与早期关于独家人畜共患性 Leishmania 传播的建议相反，我们提出在埃塞俄比亚西南部也存在 CL 的人际传播。家畜在 CL 传播中不起作用，需要在夜间采取室内外结合的控制措施来有效控制媒介。
