Hougard J M, Lochouarn L, Escaffre H, Le Goff G, Prud'hom J M, Quillévéré D
Entomologistes médicaux de l'ORSTOM, Service d'Entomologie Médicale, Centre Pasteur du Cameroun, Yaoundé.
Ann Soc Belg Med Trop. 1990 Sep;70(3):203-11.
In view of the risks of onchocerciasis facing Chadian refugees who have settled in a camp in a savanna hyperendemic area of northern Cameroon, the authors concluded that a vector control directed against the black fly larvae located on small seasonal tributaries of the main water course of this area should be carried out during the four to five months of the rainy season, i.e., during the whole period of transmission of this disease. The operations were undertaken during two consecutive rainy seasons. The first year consisted in developing ground-based control techniques and evaluating the larvicidal efficacy at the larval level. The second year was, particularly, devoted to the study of the impact of the vector control on the biting rate and on the transmission of onchocerciasis. Every week, three of the tributaries close to the camp were treated with an Emulsifiable Concentrate of temephos. Throughout the rainy season, the larvicide eliminated almost all the pre-adult black fly stages on these water courses. At the point in a high onchocercal endemicity area, it also reduced the biting rate by 60% and the Annual Transmission Potential by 72%, i.e., to values corresponding to the lower meso-endemicity threshold. Since these results were obtained at a very unfavourable point from the standpoint of black fly density and onchocerciasis transmission, the authors consider that vector control carried out under these conditions protects the local populations and the Chadian refugees effectively from black fly bites and a risk of severe onchocerciasis.
鉴于定居在喀麦隆北部热带稀树草原高流行区一个营地的乍得难民面临盘尾丝虫病风险，作者得出结论，应在雨季的四到五个月期间，即在该疾病的整个传播期，针对位于该地区主要水道小季节性支流上的蚋幼虫进行病媒控制。这些行动在连续两个雨季期间开展。第一年致力于开发地面控制技术并在幼虫层面评估杀幼虫效果。第二年尤其专注于研究病媒控制对叮咬率和盘尾丝虫病传播的影响。每周，对营地附近的三条支流使用双硫磷乳油进行处理。在整个雨季，杀幼虫剂几乎消除了这些水道上所有未成熟的蚋阶段。在盘尾丝虫病高度流行区，它还使叮咬率降低了60%，年传播潜力降低了72%，即降至对应低中流行阈值的值。由于从蚋密度和盘尾丝虫病传播的角度来看，这些结果是在非常不利的地点获得的，作者认为在这些条件下进行的病媒控制有效地保护了当地居民和乍得难民免受蚋叮咬以及严重盘尾丝虫病风险。
