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

Moussa Namountougou,Moussa Namountougou,Moussa Namountougou,Benson Georges Meda,Mahamoudou Balboné,Ahmed Coulibaly,Abdoulaye Diabaté,Abdoulaye Diabaté,Aristide Hien,Aristide Hien,Olivier Gnankiné,Parfait Eric Ouattara,Dieudonné Diloma Soma,Dieudonné Diloma Soma,Dieudonné Diloma Soma,Charles Nignan,Charles Nignan,Didier Alexandre Kaboré,Roch Kounbobr Dabiré,Didier Alexandre Kaboré,Benson Georges Meda,Samuel Drabo,Florence Fournet,Florence Fournet,Florence Fournet,Florence Fournet,Thérèse Kagoné,Roch Kounbobr Dabiré,Lassane Koala,Lassane Koala,Parfait Eric Ouattara,Mahamadi Kientega,Mahamadi Kientega

doi:10.3390/tropicalmed5020084

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 non-specific 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 Africa.

Highlights

Dengue is the most important emerging mosquito viral disease and constitutes a major public health threat in disease-endemic regions [1]
We provided evidence that insecticide multi-resistance is a common phenotype within Ae. aegypti populations from Burkina Faso, while a previous study showed that target-site mutations are widespread [33]
As no efficient vaccine against dengue fever exists, vector control relies on insecticide use and remains the main strategy to reduce the spread of dengue fever outbreaks

Summary

Introduction

Dengue is the most important emerging mosquito viral disease and constitutes a major public health threat in disease-endemic regions [1]. Dengue virus (Flaviviridae, Flavivirus) is transmitted during infected bites of Aedes female mosquitoes [1]. In Africa, Aedes aegypti remains one of the main dengue virus vectors [2]. In Burkina Faso, Ae. aegypti is assumed to be the main dengue vector in urban areas [3,4] and is characterized by a diurnal and crepuscular activity [5]. It is most frequently identified at larval stages from breeding sites such as water containers and used tires [4]

Objectives

Methods

Findings

Conclusion