Synergy between repellents and organophosphates on bed nets: efficacy and behavioural response of natural free-flying An. gambiae mosquitoes.
BACKGROUND
Chemicals are used on bed nets in order to prevent infected bites and to kill aggressive malaria vectors. Because pyrethroid resistance has become widespread in the main malaria vectors, research for alternative active ingredients becomes urgent. Mixing a repellent and a non-pyrethroid insecticide seemed to be a promising tool as mixtures in the laboratory showed the same features as pyrethroids.


RESULTS
We present here the results of two trials run against free-flying Anopheles gambiae populations comparing the effects of two insect repellents (either DEET or KBR 3023, also known as icaridin) and an organophosphate insecticide at low-doses (pirimiphos-methyl, PM) used alone and in combination on bed nets. We showed that mixtures of PM and the repellents induced higher exophily, blood feeding inhibition and mortality among wild susceptible and resistant malaria vectors than compounds used alone. Nevertheless the synergistic interactions are only involved in the high mortality induced by the two mixtures.


CONCLUSIONS
These field trials argue in favour of the strategy of mixing repellent and organophosphate on bed nets to better control resistant malaria vectors.
Pennetier
Cédric
C
UR016-Caractérisation et Contrôle des Populations de Vecteurs, Institut de Recherche pour le Développement, Montpellier, France. cedric.pennetier@ird.fr
Costantini
Carlo
C
Corbel
Vincent
V
Licciardi
Séverine
S
Dabiré
Roch K
RK
Lapied
Bruno
B
Chandre
Fabrice
F
Hougard
Jean-Marc
JM
D000483:Alleles; D000818:Animals; D000852:Anopheles / Q000502:physiology*; D001512:Bedding and Linens; D001522:Behavior, Animal; D003671:DEET / Q000008:administration & dosage; D005260:Female; D005838:Genotype; D006801:Humans; D007302:Insect Repellents / Q000494:pharmacology*; D007305:Insecticide Resistance / Q000187:drug effects* / Q000235:genetics; D008297:Male; D009032:Mosquito Control / Q000379:methods*; D057147:Mosquito Nets; D010755:Organophosphates / Q000378:metabolism*
D007302:Insect Repellents; D010755:Organophosphates; D003671:DEET