Metabolic resistance mechanism in Aedes aegypti from Lagos State, Nigeria

Abstract

Background Aedes aegypti transmits several arboviral diseases of global public health threat such as dengue, zika, and yellow fever. Recently, a series of yellow fever outbreaks have been reported in different parts of the country. Globally, the control of mosquito-borne diseases has relied heavily on insecticides based vector control efforts. Therefore, we assessed the susceptibility status to three different classes of WHO approved insecticides and evaluated the importance of detoxifying enzymes on insecticides resistance in Aedes aegypti collected from Lagos State, Nigeria. Aedes aegypti immature stages were collected from suitable habitats in peri-domestic areas of Alimosho, Kosofe, Badagry, and Ibeju-Lekki Local Government Areas (LGAs) of Lagos State, 2–5 days old glucose-fed adult female mosquitoes were exposed to discriminating doses of DDT, permethrin, bendiocarb, and PBO synergist using WHO standard procedure and kits. Identification was through morphological means only. Results Resistance to DDT and permethrin was recorded in all the LGAs, suspected resistance to bendiocarb was recorded in Aedes aegypti from Alimosho while full susceptibility was recorded in other LGAs. PBO synergist significantly increases the 24 h mortality of DDT and permethrin-resistant Aedes aegypti in all the LGAs. The activities of both GSTs and cytochrome P450s increase with decreasing mortality for Aedes aegypti, regression value (R2) ranges from 0.8889 to 0.6224 for GSTs and 0.4379 to 0.616 for cytochrome P450s. Conclusions Aedes aegypti population from Lagos State, Nigeria, have developed resistance to DDT and permethrin, the activities of P450s and GST were implicated in DDT and permethrin resistance in this study. Therefore, a need for regular insecticides monitoring and PBO should be incorporated into Aedes aegypti insecticides control strategies to forestall development of resistance to DDT and pyrethriods.

Evidence of Metabolic Resistance in Pyrethroid Resistant Aedes aegypti Population from Lagos, Nigeria

“…The bowls were scrutinized for presence of unwanted organisms or predators. Aedes mosquito larvae collected were transported in well labelled plastic bottles to the insectary in the Entomology unit of the Nigeria Institute of Medical Research, Lagos, where they were maintained and reared at a temperature of 26 ± 3°C and 74 ± 4 % relative humidity to adult stage [10]…”

“…Morphological identification of mosquitoes was done as described by [10], with the aid of a dissecting microscope. Genomic DNA was extracted from individual mosquito according to the method described by [11].…”

“…Total protein was measured for each mosquito using Biuret test [10]. All measurements were done in duplicate.…”

First Detection and Co-occurrence of kdr (F1534C and S989P) Mutations in Multiple Insecticides Resistant Aedes aegypti in Nigeria

“…However, resistance to insecticides is being reported in different mosquito species including Aedes aegypti in various parts of the world. In Nigeria, resistance to DDT, pyrethroids and carbamates have been reported in Aedes aegypti from different parts of the country [5][6][7][8]. Insecticide resistances in mosquitoes in mainly as a result of the activities of detoxifying enzymes and mutation of the target sites.…”

“…Detoxification enzymes that have been linked to insecticide resistance include, cytochrome P450 monooxygenases (P450s), carboxylesterases (COEs), and glutathione S-transferases (GSTs). The impact of these detoxifying enzymes in the resistance phenotype expressed by Aedes mosquitoes has been highlighted in some studies in different parts of the world [7][8][9][10][11]. Knockdown resistance (kdr) has been described and associated in DDT and pyrethroid resistance in Aedes [12].…”