Biodiversity and ecology of Culicidae and Simuliidae probable vectors of infectious diseases in villages of the Sanaga mid valley, Cameroon: Influence of the Sanaga River

摘要

Most riverine villages of the Sanaga river are known endemic for vector-borne diseases. Two cross sectional surveys were set during two seasons in villages of the Sanaga mid valley to identify main Simuliids and mosquitoes genus and species, their specific biotopes and fluctuations of their abundance with respect to distance from the river banks and seasons. The study villages are located close to 5 and 35 km from the Sanaga river edges. Both larva and adult stages were assessed using known methods. All adults Simuliids, larvae and nymphs were identified as Simulium damnosum. Larvae and nymphs were collected only in the river stream and adults near the banks, farms and near households. Adults and larvae abundance was greater in the rainy season whereas nymphs were more abundant in the dry season. Endophilic mosquitoes harvested were Anopheles and Culex. Their abundance was greater in villages close to the river. Species and resting densities varied with distance from the river edges. Culicidae larvae collected belonged to Aedes, Anopheles and Culex. Fourteen species were identified, 3 of Anopheles, 5 of Aedes and 6 of Culex. Some species showed broad specificity to biotopes. This study indicates that mosquito fauna is more diversified at larval stage in the Sanaga mid valley; some having broad specificity to breading sites. The Sanaga river harbours most of the species found in the water bodies. Indoor adult mosquitoes are less diversified indicating that most of the mosquito found at larval stage may breed mostly outdoor. Simulium larvae and pupae breed specifically in the falls and rapids of the Sanaga stream. Both sexes of adult Simulium are found near the river, whereas only females are found near households and in farms. Adults Simulium density decreases with the distance from the river with two picks of abundance in the day.