Oforka Linda C, Adeleke Monsuru A, Anikwe Joseph C, Makanjuola Winifred A
Department of Zoology, University of Lagos, Lagos, Nigeria.
Department of Biological Sciences, Osun State University, Osogbo, Nigeria.
Environ Entomol. 2019 Apr 3;48(2):284-290. doi: 10.1093/ee/nvz004.
Simulium damnosum (Theobald) sensu lato (s.l.) is a complex of many species of black flies that transmit Onchocerca volvulus (Leuckart) to varying capacities based on their ecological zones in Africa. The presence of three ecological zones in Osun, an onchocerciasis endemic state in Nigeria, is the basis of this study that is aimed at determining the population dynamics of S. damnosum s.l. in the state. Adult S. damnosum s.l. were collected fortnightly in the wet and dry seasons for 2 yr between October 2014 and September 2016 in the Guinea savanna (Iwo), derived savannah (Ede), and rainforest (Obokun) zones. Temperature, relative humidity, and rainfall of the study area were measured. The results showed that in the first year, Ede had 62.8% of the total black fly population while Obokun had the lowest (1.5%). In the second year, Iwo had 94.1% of the total black fly population while Obokun had the least population. The black fly population was significantly higher during the wet season than dry season in Iwo and Ede, but was not significant in Obokun. The results further showed that black fly populations were strongly correlated with ambient temperature and rainfall in Iwo, whereas no relationships were recorded for Ede and Obokun. The results suggest that abundance of black flies during the wet season was due to increased rainfall which in turn created rapids and conditions suitable for development of preimaginal stages into adults. These vector surveillance findings will guide control decisions necessary for endemic communities to meet elimination targets.
广布蚋（Theobald）复合种是多种黑蝇的复合体，它们根据在非洲的生态区域，以不同能力传播旋盘尾丝虫（Leuckart）。尼日利亚盘尾丝虫病流行州奥孙存在三个生态区域，本研究以此为基础，旨在确定该州广布蚋复合种的种群动态。2014年10月至2016年9月的两年间，在雨季和旱季每两周收集一次广布蚋复合种成虫，采集地点分别为几内亚稀树草原（伊沃）、衍生稀树草原（埃代）和雨林（奥博昆）区域。对研究区域的温度、相对湿度和降雨量进行了测量。结果显示，第一年，埃代的黑蝇总数占62.8%，而奥博昆的数量最少（1.5%）。第二年，伊沃的黑蝇总数占94.1%，而奥博昆的数量最少。在伊沃和埃代，雨季的黑蝇数量显著高于旱季，但在奥博昆不显著。结果还表明，伊沃的黑蝇数量与环境温度和降雨量密切相关，而埃代和奥博昆则没有这种关系。结果表明，雨季黑蝇数量增加是由于降雨量增加，进而形成了急流以及适合幼虫发育为成虫的条件。这些媒介监测结果将指导流行社区实现消除目标所需的控制决策。
