Journal Article

Insecticide resistance status and mechanisms in Aedes aegypti populations from Senegal

Sene, Ndeye Marie, Diallo, Diawo, Ngom, El Hadji Malick, Vontas, John, Mavridis, Konstantinos, Diagne, Cheikh Tidiane, Ba, Yamar, Dia, Ibrahima, Ndiaye, El Hadji, Gaye, Alioune, Diallo, Mawlouth

2021

Overview

Aedes aegypti is the main epidemic vector of arboviruses in Africa. In Senegal, control activities are mainly limited to mitigation of epidemics, with limited information available for Ae . aegypti populations. A better understanding of the current Ae . aegypti susceptibility status to various insecticides and relevant resistance mechanisms involved is needed for the implementation of effective vector control strategies. The present study focuses on the detection of insecticide resistance and reveals the related mechanisms in Ae . aegypti populations from Senegal. Bioassays were performed on Ae . aegypti adults from nine Senegalese localities (Matam, Louga, Barkedji, Ziguinchor, Mbour, Fatick, Dakar, Kédougou and Touba). Mosquitoes were exposed to four classes of insecticides using the standard WHO protocols. Resistance mechanisms were investigated by genotyping for pyrethroid target site resistance mutations (V1016G, V1016I, F1534C and S989P) and measuring gene expression levels of key detoxification genes ( CYP6BB2 , CYP9J26 , CYP9J28 , CYP9J32 , CYP9M6 , CCEae3a and GSTD4 ). All collected populations were resistant to DDT and carbamates except for the ones in Matam (Northern region). Resistance to permethrin was uniformly detected in mosquitoes from all areas. Except for Barkédji and Touba, all populations were characterized by a susceptibility to 0.75% Permethrin. Susceptibility to type II pyrethroids was detected only in the Southern regions (Kédougou and Ziguinchor). All mosquito populations were susceptible to 5% Malathion, but only Kédougou and Matam mosquitoes were susceptible to 0.8% Malathion. All populations were resistant to 0.05% Pirimiphos-methyl, whereas those from Louga, Mbour and Barkédji, also exhibited resistance to 1% Fenitrothion. None of the known target site pyrethroid resistance mutations was present in the mosquito samples included in the genotyping analysis (performed in > 1500 samples). In contrast, a remarkably high (20-70-fold) overexpression of major detoxification genes was observed, suggesting that insecticide resistance is mostly mediated through metabolic mechanisms. These data provide important evidence to support dengue vector control in Senegal.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adults / Aedes / drug effects / Aedes / genetics / Aedes / metabolism / Aedes aegypti / Animal biology / Animal genetics / Animals / Aquatic insects / Bioassays / Biochemistry, Molecular Biology / Biological assays / Biology and Life Sciences / Dengue / Dengue fever / Disease control / Disease transmission / Epidemics / Females / Gene Expression / Genetic aspects / Genetics / Genomics / Guillain-Barre syndrome / Health risks / Human diseases / Humidity / Inactivation, Metabolic / genetics / Insecticide resistance / Insecticide Resistance / genetics / Insecticides / Insects / Invertebrate Zoology / Life Sciences / Medicine and Health Sciences / Mosquito Vectors / drug effects / Mosquito Vectors / genetics / Mosquito Vectors / metabolism / Mosquitoes / Mutation / People and Places / Pest outbreaks / Pesticide resistance / Physiological aspects / Public health / Pyrethrins / Research and Analysis Methods / Santé publique et épidémiologie / Senegal / Strains / Tropical climate / Tropical diseases / Vaccines / Vector-borne diseases / Viruses / Zika virus