Nouvel aperçu sur l’écologie larvaire d’Anopheles coluzzii Coetzee et Wilkerson, 2013 dans l’estuaire du Wouri, Littoral-Cameroun

Abstract

Malaria vectors control is essentially based on the use of insecticides against adult mosquitoes. However because of the development of resistance to insecticides, there is now a renewed interest in the management of larval sources. The aim of the present study was to map and characterize the breeding sites of Anopheles coluzzii in the Wouri river estuary in Cameroon. Larval surveys were carried out between December 2013 and August 2014 in rural areas on the island of Manoka and urban area in Youpwe at Douala. Culicidae breeding sites identified were georeferenced and mapped. Their larval productivity was evaluated by the method of "dipping" and their physicochemical parameters measured by spectrophotometry and oximetry. Culicidae collected larvae were reared in the insectarium to the adult stage. Adult mosquitoes were subjected to morphological identification and those belonging to the Anopheles gambiae complex have subsequently been subjected to molecular identification by the PCR-RFLP technique. A total of 240 breeding sites were geo-referenced in the two sites, including 10 types. Abandoned containers and pools were the most frequent breeding sites respectively in Manoka and in Youpwe. After morphological and molecular identification, eleven mosquito species have been identified. Anopheles coluzzii and Culex quinquefasciatus were the most frequent species respectively in Manoka and in Youpwe. Mosquito density was higher in managed gutters and canoes respectively in Manoka and in Youpwe. Culex and Aedes genus were more frequent in the hollow palm and water wells respectively in Manoka and Youpwe. The productivity of breeding sites varied according to the physicochemical parameters. Species richness varied according to the type of breeding site. Anopheles coluzzii was observed for the first time in Cameroon in water storage containers, tires, discarded containers and canoes. This study highlighted diversity in the type of breeding site of An. coluzzii in the Wouri estuary, suggesting the adaptation of this species in its environment. These results could be used to develop an antilarval control strategy in Manoka and in Youpwe.

Spatial distribution of Anopheles gambiae sensu lato larvae in the urban environment of Yaoundé, Cameroon

“…larvae were found to colonize a large number of habitats including temporary water collections, permanent sites and artificial habitats. This was in accordance with the high adaptation capacity of the species in urban settings [22, 48–50]. An.…”

Artisanal fishing supports breeding of malaria mosquitoes in Western Kenya

“…Two recent studies document utilization of boats for breeding by Anopheles coluzzii (initially the M form of An. gambiae sensu lato) in two fishing communities within the Wouri river estuary near the port of Duala in Cameroon [53, 54]. Data in this article corroborate these findings, albeit with respect to An.…”

“…gambiae s.s., which was the only Anopheles species identified on Mageta Island. Mbida et al [54] explain the phenomenon of An. coluzzii breeding in boats, among other man-made habitats, as an adaptation to utilizing artificial habitats when natural ones become rare.…”

Ecological plasticity to ions concentration determines genetic response and dominance of Anopheles coluzzii larvae in urban coastal habitats of Central Africa

“…Anopheles coluzzii ecological success is illustrated by its phenotypic plasticity 34 , 77 , 78 . At the larval stage, this mosquito exhibits an extraordinary adaptability to develop in a great variety of breeding sites 22 , 79 – 82 , with a preference for more permanent ones 83 . Our study confirmed the wide range of aquatic conditions where this species can lay and develop, in coastal and urban settings of Central Africa.…”