Journal of Infectious Diseases & Therapy
Open Access

Abstract

Objective: Insecticide resistance in mosquitoes is potentially threatening the control of malaria. However, the ability of resistant mosquitoes to transmit malaria may be altered by reduced fitness associated with insecticide resistance (IR) genes. This study explored the fitness costs associated with L119F-GSTe2 (a single gene mutation which confers resistance against DDT) in an An. funestus population in Cameroon. Methodology: Mosquito collections were carried out in Obout, Cameroon. Bioassays were performed on reared F1 An. funestus and cone assays were performed on 5 commercial nets. Molecular analysis included PCR species identification of An. funestus from extracted gDNA and TaqMan assays for Plasmodium infection and GSTe2-L119F gene mutation. Oviposition rate was recorded for 100 F0 An. funestus but could not be compared between resistant and susceptible mosquitoes (with and without GSTe2-L119F mutation respectively) due to unforeseen circumstances. Results: The Plasmodium infection rate in the Obout An. funestus (20% for P. falciparum) was significantly higher than previously recorded in the north of Cameroon. Bioassays demonstrated resistance against all classes of insecticides except for the organophosphates. Of the nets tested in the cone assay, only the top of PermaNet�® 3.0 demonstrated full efficacy and suspiciously, Olyset�® net showed complete loss of efficacy. Conclusion: This study has unfortunately had setbacks due to problems with chemical reagents. Nevertheless, this is the first study to characterize the resistance profile of An. Funestus mosquitoes in Cameroon. The collected An. funestus were confirmed as a major Plasmodium vector and based on the bioassay results, organophosphates should be encouraged for use in indoor residual spraying. Tighter inspection and examination of nets sold in Cameroon is required as Olyset�® net that is available in local pharmacies was suspected to be forged.

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