Nopowo F N, Akono Ntonga P, Tonga C, Offono Enama L, Mbida Mbida A, Kekeunou S
Laboratoire de biologie et physiologie des organismes animaux, département de biologie et organismes animaux, faculté des sciences, université de Douala, BP 24157 Douala, Cameroun.
Laboratoire de zoologie, département de biologie et physiologie animale, faculté des sciences, université de Yaoundé-I, BP 812 Yaoundé, Cameroun.
Bull Soc Pathol Exot. 2019;112(5):302-310. doi: 10.3166/bspe-2020-0109.
Anopheles hancocki is one of the secondary vectors of malaria whose larval ecology in the South Cameroonian forest block is still unknown. This information is however fundamental for developing efficient and sustainable control strategies against this mosquito in localities where it acts as a disease vector. The present study describes the larval ecology of A. hancocki and its contribution in malaria transmission in a riverbank village of the Ayos Health District. Mosquito sampling took place in 2018 on a quarterly rate, combining the dipping method for larval collection with adult mosquito capture on volunteers. For each of the breeding sites, physicochemical characteristics were measured and larvae were collected and reared to adult. Molecular alongside morpho-taxonomic techniques were used for the identification of mosquito species. Physiological age was determined based on the appearance of their ovarian tracheoles and CSP Elisa test was used to assess infectivity. In total, 3,618 adult mosquitoes belonging to seven species were collected in the study area, namely A. hancocki, Anopheles gambiae, Anopheles moucheti, Mansonia africana, Culex pipiens quinquefasciatus, Aedes albopictus and Aedes aegypti. Breeding sites of A. hancocki were similar to those of A. gambiae. However, the total dissolved solids and conductivity values were significantly higher in A. gambiae breeding sites than in those of A. hancocki. A. hancocki was the most aggressive mosquito species and represented 45.6% of the local aggressive culicidofauna. Male species' nocturnal cycle of aggression showed maximum activity between 8 pm and 10 pm. Females of this species were significantly older than those of A. gambiae and contributed to 40% of malaria transmission in the locality with an average annual Entomological Inoculation Rate (EIR) of 2.92 ib/p/year lower than that of A. gambiae (3.65 ib/p/year). Except few differences, ecological requirements for the development of A. hancocki larvae are similar to that of A. gambiae. A. hancocki contributes to the perennial transmission of malaria in the Ayos area; implementation of vector control strategies is therefore needed.
汉氏按蚊是疟疾的次要传播媒介之一，其在喀麦隆南部森林地区的幼虫生态仍不为人知。然而，对于在该蚊作为疾病传播媒介的地区制定高效且可持续的蚊虫控制策略而言，这些信息至关重要。本研究描述了汉氏按蚊的幼虫生态及其在阿约斯健康区一个河岸村庄疟疾传播中的作用。2018年按季度进行蚊虫采样，采用勺舀法收集幼虫，并在志愿者身上捕捉成蚊。对于每个繁殖地，测量其理化特征，收集幼虫并饲养至成虫。分子技术与形态分类技术相结合用于鉴定蚊虫种类。根据卵巢气管的外观确定生理年龄，并使用CSP酶联免疫吸附测定法评估感染性。在研究区域共收集到3618只属于7个种类的成蚊，分别为汉氏按蚊、冈比亚按蚊、穆氏按蚊、非洲曼蚊、致倦库蚊、白纹伊蚊和埃及伊蚊。汉氏按蚊的繁殖地与冈比亚按蚊的相似。然而，冈比亚按蚊繁殖地的总溶解固体和电导率值显著高于汉氏按蚊繁殖地。汉氏按蚊是最具攻击性的蚊虫种类，占当地攻击性库蚊类群的45.6%。该蚊种雄性的夜间攻击周期在晚上8点至10点之间活动最为频繁。该蚊种的雌蚊比冈比亚按蚊的雌蚊明显更年长，且在当地疟疾传播中占40%，其年均昆虫接种率（EIR）为2.92只感染性按蚊/人/年，低于冈比亚按蚊（3.65只感染性按蚊/人/年）。除了一些差异外，汉氏按蚊幼虫发育的生态需求与冈比亚按蚊相似。汉氏按蚊促成了阿约斯地区疟疾的常年传播；因此需要实施病媒控制策略。
