Monitoring Insecticide Susceptibility in Aedes Aegypti Populations from the Two Biggest Cities, Ouagadougou and Bobo-Dioulasso, in Burkina Faso: Implication of Metabolic Resistance

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Résumé

Abstract: In West Africa, Aedes aegypti remains the major vector of dengue virus. Since 2013, dengue
fever has been reemerging in Burkina Faso with annual outbreaks, thus becoming a major public
health problem. Its control relies on vector control, which is unfortunately facing the problem of
insecticide resistance. At the time of this study, although data on phenotypic resistance were
available, information related to the metabolic resistance in Aedes populations from Burkina Faso
remained very scarce. Here, we assessed the phenotypic and the metabolic resistance of Ae. aegypti
populations sampled from the two main urban areas (Ouagadougou and Bobo-Dioulasso) of
Burkina Faso. Insecticide susceptibility bioassays to chlorpyriphos-methyl 0.4%, bendiocarb 0.1%
and deltamethrin 0.05% were performed on natural populations of Ae. aegypti using the WHO
protocol. The activity of enzymes involved in the rapid detoxification of insecticides, especially nonspecific esterases, oxidases (cytochrome P450) and glutathione-S-transferases, was measured on
individual mosquitos. The mortality rates for deltamethrin 0.05% were low and ranged from 20.72%
to 89.62% in the Bobo-Dioulasso and Ouagadougou sites, respectively. When bendiocarb 0.1% was
tested, the mortality rates ranged from 7.73% to 71.23%. Interestingly, in the two urban areas,
mosquitoes were found to be fully susceptible to chlorpyriphos-methyl 0.4%. Elevated activity of
non-specific esterases and glutathione-S-transferases was reported, suggesting multiple resistance
mechanisms involved in Ae. aegypti populations from Bobo-Dioulasso and Ouagadougou (including
cytochrome P450). This update to the insecticide resistance status within Ae. aegypti populations in
the two biggest cities is important to better plan dengue vectors control in the country and provides
valuable information for improving vector control strategies in Burkina Faso, West Afric

Mots-clés

Aedes aegypti; Dengue; Insecticide susceptibility; Metabolic Resistance; Burkina Faso