Back to Search
Start Over
Insecticide resistance status of three malaria vectors, Anopheles gambiae (s.l.), An. funestus and An. mascarensis, from the south, central and east coasts of Madagascar.
- Source :
-
Parasites & vectors [Parasit Vectors] 2017 Aug 23; Vol. 10 (1), pp. 396. Date of Electronic Publication: 2017 Aug 23. - Publication Year :
- 2017
-
Abstract
- Background: Insecticide-based vector control, which comprises use of insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS), is the key method to malaria control in Madagascar. However, its effectiveness is threatened as vectors become resistant to insecticides. This study investigated the resistance status of malaria vectors in Madagascar to various insecticides recommended for use in ITNs and/or IRS.<br />Methods: WHO tube and CDC bottle bioassays were performed on populations of Anopheles gambiae (s.l.), An. funestus and An. mascarensis. Adult female An. gambiae (s.l.) mosquitoes reared from field-collected larvae and pupae were tested for their resistance to DDT, permethrin, deltamethrin, alpha-cypermethrin, lambda-cyhalothrin, bendiocarb and pirimiphos-methyl. Resting An. funestus and An. mascarensis female mosquitoes collected from unsprayed surfaces were tested against permethrin, deltamethrin and pirimiphos-methyl. The effect on insecticide resistance of pre-exposure to the synergists piperonyl-butoxide (PBO) and S,S,S-tributyl phosphorotrithioate (DEF) also was assessed. Molecular analyses were done to identify species and determine the presence of knock-down resistance (kdr) and acetylcholinesterase resistance (ace-1 <superscript>R</superscript> ) gene mutations.<br />Results: Anopheles funestus and An. mascarensis were fully susceptible to permethrin, deltamethrin and pirimiphos-methyl. Anopheles gambiae (s.l.) was fully susceptible to bendiocarb and pirimiphos-methyl. Among the 17 An. gambiae (s.l.) populations tested for deltamethrin, no confirmed resistance was recorded, but suspected resistance was observed in two sites. Anopheles gambiae (s.l.) was resistant to permethrin in four out of 18 sites (mortality 68-89%) and to alpha-cypermethrin (89% mortality) and lambda-cyhalothrin (80% and 85%) in one of 17 sites, using one or both assay methods. Pre-exposure to PBO restored full susceptibility to all pyrethroids tested except in one site where only partial restoration to permethrin was observed. DEF fully suppressed resistance to deltamethrin and alpha-cypermethrin, while it partially restored susceptibility to permethrin in two of the three sites. Molecular analysis data suggest absence of kdr and ace-1 <superscript>R</superscript> gene mutations.<br />Conclusion: This study suggests involvement of detoxifying enzymes in the phenotypic resistance of An. gambiae (s.l.) to pyrethroids. The absence of resistance in An. funestus and An. mascarensis to pirimiphos-methyl and pyrethroids and in An. gambiae (s.l.) to carbamates and organophosphates presents greater opportunity for managing resistance in Madagascar.
- Subjects :
- Acetylcholinesterase genetics
Acetylcholinesterase metabolism
Animals
Anopheles genetics
Female
Insecticide-Treated Bednets
Larva drug effects
Madagascar epidemiology
Malaria epidemiology
Mosquito Control methods
Mutation
Nitriles pharmacology
Permethrin pharmacology
Pupa drug effects
Pyrethrins pharmacology
Anopheles drug effects
Insecticide Resistance genetics
Insecticides pharmacology
Malaria prevention & control
Subjects
Details
- Language :
- English
- ISSN :
- 1756-3305
- Volume :
- 10
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Parasites & vectors
- Publication Type :
- Academic Journal
- Accession number :
- 28835269
- Full Text :
- https://doi.org/10.1186/s13071-017-2336-9