Evaluation of synthetic repellents on mosquito nets in experimental huts against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes.
Owing to the development of pyrethroid resistance in Anopheles gambiae, there is a need to develop chemical alternatives for use on mosquito nets. Synthetic insect repellents are widely used for personal protection as skin or clothing applications. The efficacy of repellent-treated nets (RTN) was evaluated in experimental huts in Côte d'Ivoire against pyrethroid-resistant populations of An. gambiae and Culex quinquefasciatus. The repellents tested were DEET (N,N-diethyl-3-methylbenzamide) at 7.9 g/m2 and two formulations of ethyl butylacetylaminopropionate (IR3535) at 7.6 g/m2 and 7.3 g/m2. Over 45 nights there was a 74-82% reduction in the number of An. gambiae entering the huts containing RTNs but no significant reduction in entry of C. quinquefasciatus. There was a 63-64% reduction in the proportion of An. gambiae blood feeding but no reduction in the proportion of C. quinquefasciatus blood feeding in huts with RTNs. An unexpected result was the 69-76% mortality of An. gambiae and 51-61% mortality of C. quinquefasciatus in huts containing RTNs. Treated filter paper bioassays in WHO test kits confirmed that confined contact with DEET induces mortality. The DEET-based product provided better and longer protection; tunnel test bioassays confirmed that residual activity lasted for up to 6 weeks. Application of repellents to nets warrants further investigation and development.
N'Guessan
Raphael
R
Gates Malaria Partnership, London School of Hygiene and Tropical Medicine, 50 Bedford Square, London, UK. raphael.n'guessan@lshtm.ac.uk
Rowland
Mark
M
Moumouni
Traore-Lamizana
TL
Kesse
Nestor Bli
NB
Carnevale
Pierre
P
D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D001512:Bedding and Linens; D001681:Biological Assay; D003465:Culex / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007299:Insect Bites and Stings / Q000469:parasitology; D007302:Insect Repellents / Q000008:administration & dosage / Q000494:pharmacology*; D007305:Insecticide Resistance; D008297:Male; D009032:Mosquito Control / Q000295:instrumentation* / Q000379:methods; D015996:Survival Rate
D007302:Insect Repellents