Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males of the African malaria vector, Anopheles funestus

Wellcome Open Research

article

Magellan Tchouakui¹  Billy Tene Fossog²  Brigitte Vanessa Ngannang²  Doumani Djonabaye²  Williams Tchapga²  Flobert Njiokou¹  Charles S. Wondji² 

[1] Department of Animal Biology and Physiology, Faculty of Science, University of Yaoundé 1;Department of Medical Entomology, Centre for Research in Infectious Diseases;Department of Biochemistry, University of Yaoundé 1;Department of Vector Biology, Liverpool School of Tropical Medicine

关键词: Malaria;    insecticides;    metabolic resistance;    Glutathione S-transferase;    Anopheles funestus;    mating competitiveness;   

DOI  :  10.12688/wellcomeopenres.15013.2

学科分类：内科医学

来源: Wellcome

【 摘 要 】

Background: Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of maleAnopheles funestus, in Cameroon.Methods: Swarms and indoor resting collections took place in March, 2018 in Tibati, Cameroon. WHO tube and cone assays were performed on F1 mosquitoes from indoor collected females to assess the susceptibility profile of malaria vectors. Mosquitoes mated and unmated males collected in the swarms were genotyped for the L119F metabolic marker to assess its association with mating male competitiveness.Results: Susceptibility and synergist assays, showed that this population was multiple resistant to pyrethroids, DDT and carbamates, likely driven by metabolic resistance mechanisms. Cone assays revealed a reduced efficacy of standard pyrethroid-nets (Olyset and PermaNet 2.0) with low mortality (80%). The L119F-GSTe2 mutation, conferring pyrethroid/DDT resistance, was detected in thisAn. funestus population at a frequency of 28.8%. In addition, a total of 15 mating swarms were identified and 21An. funestus couples were isolated from those swarms.  A comparative genotyping of the L119F-GSTe2 mutation between mated and unmated males revealed that heterozygote males 119L/F-RS were less able to mate than homozygote susceptible (OR=7.2, P<0.0001). Surprisingly, heterozygote mosquitoes were also less able to mate than homozygote resistant (OR=4.2, P=0.010) suggesting the presence of a heterozygote disadvantage effect. Overall, mosquitoes bearing the L119-S susceptible allele were significantly more able to mate than those with 119F-R resistant allele (OR=2.1, P=0.03).Conclusion: This study provides preliminary evidences that metabolic resistance potentially exerts a fitness cost on mating competiveness in resistant mosquitoes.

【 授权许可】

CC BY