Pyrethroid cross resistance spectrum among populations of Anopheles gambiae s.s. from Côte d'Ivoire.
Field samples of Anopheles gambiae s.s. from Côte d'Ivoire were tested with 5 pyrethroids (cyfluthrin, lambda-cyhalothrin, alpha-cypermethrin, deltamethrin, permethrin), 1 pseudo-pyrethroid (etofenprox), and an organochlorine (DDT). With the use of World Health Organization diagnostic tests, 5 out of 6 samples were found cross-resistant to these insecticides. A strong decrease in knockdown effect and mortality was also observed when testing deltamethrin-impregnated nettings. With a polymerase chain reaction amplification of specific alleles diagnostic test, resistance was found associated with the presence of a kdr mutation. The strong correlation between kdr allelic frequency and resistance to DDT or etofenprox indicated that kdr was the main resistance factor for these 2 insecticides. On the contrary, a lower correlation was observed between kdr frequency and resistance to 4 of the 5 pyrethroids tested, suggesting that another mechanism was also involved, likely a metabolic detoxification. These results point out the necessity to monitor pyrethroid resistance and the presence of kdr before implementation of any impregnated bed-net programs for malaria control.
Chandre
F
F
ORSTOM, Laboratoire de Lutte contre les Insectes Nuisibles, Montpellier, France.
Darriet
F
F
Manguin
S
S
Brengues
C
C
Carnevale
P
P
Guillet
P
P
D000483:Alleles; D000818:Animals; D000852:Anopheles / Q000235:genetics*; D007560:Cote d'Ivoire; D005787:Gene Frequency; D007305:Insecticide Resistance; D009032:Mosquito Control / Q000379:methods; D009570:Nitriles; D011722:Pyrethrins
D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin