Higher Institute for Scientific and Medical Research (ISM), Yaoundé, Cameroon.
Parasitology and Ecology Laboratory, Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.
Parasit Vectors. 2023 Aug 4;16(1):262. doi: 10.1186/s13071-023-05832-y.
Reducing contact between humans and black flies can lead to interruption of onchocerciasis transmission. The Esperanza Window Trap (EWT) has been shown to be an effective tool for reducing black fly densities. Several shape-based improvements to this trapping system have been made to optimise its effectiveness, but optimisation of this trapping system has been based most often on the shape of the trap, collection in areas of high black fly density and the addition of attractants, without considering transmission potentials and parity rates. This study aims to investigate the differences in biting rates and transmission potential between three catch points along a transect to guide the choice of EWT placement.
Monthly black fly collection was carried out over a 1-year study period using the human landing method at three catch points along a transect from the riverside toward the centre of two first-line villages (Biatsota and Bayomen), in the Mbam valley in Cameroon. All female black flies caught were counted and dissected, and entomological indicators were computed and compared between the catch points and villages.
A total of 80,732 black flies were caught, of which 57,517 were dissected; of the latter, 2743 (4.8%) were parous and 44 (1.6%) were infective. Regarding the distance to the river, a vector density gradient was observed, with the highest annual biting rates being recorded at the riverside. The highest annual transmission potentials were also recorded at the riverside (165 vs 255 infective larvae/man/year in Bayomen and Biatsota, respectively). Overall, the highest parity rates were recorded at the riverside in Biatsota (5.1%) where various human activities are frequent and at the centre of Bayomen village (6.3%).
The results of this study reveal that entomological parameters were the highest at the riverside catch sites and indicate that riverside locations should be prioritised for EWTs or other trapping systems to achieve optimal performance in onchocerciasis control.
减少人与黑蝇的接触可导致盘尾丝虫病传播中断。埃斯佩兰萨窗口陷阱（EWT）已被证明是降低黑蝇密度的有效工具。为了优化其效果，对该诱捕系统进行了几种基于形状的改进，但这种诱捕系统的优化大多基于陷阱的形状、在黑蝇密度高的区域进行收集以及添加引诱剂，而没有考虑传播潜力和均等率。本研究旨在调查沿一条横断线上三个捕捉点的叮咬率和传播潜力的差异，以指导 EWT 的放置选择。
在喀麦隆姆巴姆河谷的两个一线村庄（比亚措塔和巴约门），从河边到中心，沿一条横断线上的三个捕捉点，使用人体着陆法，进行为期一年的黑蝇每月收集。对捕获的所有雌性黑蝇进行计数和解剖，并计算和比较各捕捉点和村庄之间的昆虫学指标。
共捕获 80732 只黑蝇，其中 57517 只被解剖；其中，2743 只（4.8%）为多产，44 只（1.6%）为感染性。关于到河流的距离，观察到一个向量密度梯度，河边的年叮咬率最高。河边的年传播潜力也最高（分别为 165 和 255 感染性幼虫/人/年，在巴约门和比亚措塔）。总的来说，河边比亚措塔的最高均等率最高（5.1%），那里经常有各种人类活动，而巴约门中心的均等率最高（6.3%）。
本研究结果表明，河边的昆虫学参数最高，并表明河边的位置应优先考虑使用 EWT 或其他诱捕系统，以在盘尾丝虫病控制中实现最佳性能。
