Analyses of Insecticide Resistance Genes in Aedes aegypti and Aedes albopictus Mosquito Populations from Cameroon.

Borel Djiappi-Tchamen,Elysée Nchoutpouen,Christophe Antonio-Nkondjio,Abdou Talipouo,Timoléon Tchuinkam,Parfait Awono-Ambene,Idene Makoudjou,Konstantinos Mavridis,Mariette Stella Nana-Ndjangwo,John Vontas,Audrey Marie Paul Mayi,Roland Bamou

doi:10.3390/genes12060828

Abstract

The emergence of insecticide resistance in Aedes mosquitoes could pose major challenges for arboviral-borne disease control. In this paper, insecticide susceptibility level and resistance mechanisms were assessed in Aedes aegypti (Linnaeus, 1762) and Aedes albopictus (Skuse, 1894) from urban settings of Cameroon. The F1 progeny of Aedes aegypti and Aedes albopictus collected in Douala, Yaoundé and Dschang from August to December 2020 was tested using WHO tube assays with four insecticides: deltamethrin 0.05%, permethrin 0.75%, DDT 4% and bendiocarb 0.1%. TaqMan, qPCR and RT-qPCR assays were used to detect kdr mutations and the expression profiles of eight detoxification genes. Aedes aegypti mosquitoes from Douala were found to be resistant to DDT, permethrin and deltamethrin. Three kdr mutations, F1534C, V1016G and V1016I were detected in Aedes aegypti populations from Douala and Dschang. The kdr allele F1534C was predominant (90%) in Aedes aegypti and was detected for the first time in Aedes albopictus (2.08%). P450s genes, Cyp9J28 (2.23–7.03 folds), Cyp9M6 (1.49–2.59 folds), Cyp9J32 (1.29–3.75 folds) and GSTD4 (1.34–55.3 folds) were found overexpressed in the Douala and Yaoundé Aedes aegypti populations. The emergence of insecticide resistance in Aedes aegypti and Aedes albopictus calls for alternative strategies towards the control and prevention of arboviral vector-borne diseases in Cameroon.

Highlights

IntroductionArboviral diseases such as dengue and chikungunya have been increasingly reported across sub-Saharan Africa with important outbreaks reported in major urban settings [7,8,9,10,11,12,13,14,15]
Albopictus populations were fully susceptible to permethrin and deltamethrin insecticides, while Ae. aegypti from Douala displayed high resistance to both deltamethrin 0.05% and permethrin 0.75%
The rapid expansion of insecticide resistance in this species could result from domestic pollution or organic pollutants since Aedes albopictus is largely prevalent in water containers, spare tires, and discarded containers, which happen to be largely prevalent in agricultural cultivated sites [68]

Summary

Introduction

Arboviral diseases such as dengue and chikungunya have been increasingly reported across sub-Saharan Africa with important outbreaks reported in major urban settings [7,8,9,10,11,12,13,14,15]. These changes in the epidemiology of arboviral diseases could be closely linked to the co-occurrence of these two competent vector species in most epidemiological settings [16,17,18,19,20].

Results

Discussion

Conclusion