[Competitive Adaptation of Aedes albopictus, Skuse 1894 in the Presence of Aedes aegypti Linné 1862 in Temporary Larvae Breeding Sites and in the Context of Pyrethroids Resistance in Douala(Cameroon)].

Abstract

Aedes albopictus and Aedes aegypti are two potential vectors of arboviruses in Douala. Knowing their breeding behaviour and insecticide resistance status would allow for better design of control activities. Mosquito larvae and nymphs were captured from breeding sites from July to September 2017, in Ndogbong, PK21 and Yassa, three neighbourhoods of the city of Douala, with ecological peculiarities. They were reared to adults and then identified to species. Female mosquitoes aged 3 to 5 days, not fed on blood, were tested for pyrethroid sensibility. Overall, 144 breeding artificial and natural sites were identified in the 3 neighbourhoods. A. albopictus was the single species found in most of the breeding sites (64.6%), whereas A. aegypti was found only in 4 sites (2.8%). Both species lived sympatrically in 47 sites (32.6%). Morphological identification of 8,160 adults revealed a significantly higher abundance of A. albopictus compared with A. aegypti (88.8% versus 11.2%). Insecticide resistance test with deltamethrin and permethrin revealed resistance in female A. aegypti and A. albopictus from Ndogbong and Yassa (mortality rates ‹ 92%). A. albopictus shows better adaptation to artificial breeding sites in Douala and their resistance to recommended insecticides calls for new insecticidal molecules.