title: Efficacy of bifenthrin-impregnated bednets against Anopheles funestus and pyrethroid-resistant Anopheles gambiae in North Cameroon.
abstract: BACKGROUND
  Recent field studies indicated that insecticide-treated bednets (ITNs) maintain their efficacy despite a high frequency of the knock-down resistance (kdr) gene in Anopheles gambiae populations. It was essential to evaluate ITNs efficacy in areas with metabolic-based resistance.
  
  
  METHODS
  Bifenthrin was used in this experiment because it is considered a promising candidate for bednets impregnation. Nets were treated at 50 mg/m2, a dose that has high insecticidal activity on kdr mosquitoes and at 5 mg/m2, a dose that kills 95% of susceptible mosquitoes under laboratory conditions with 3 minutes exposure. Bednets were holed to mimic physical damage. The trial was conducted in three experimental huts from Pitoa, North-Cameroon where Anopheles gambiae displays metabolic resistance and cohabits with An. funestus.
  
  
  RESULTS
  Bifenthrin at 50 mg/m2 significantly reduced anophelines' entry rate (>80%). This was not observed at 5 mg/m2. Both treatments increased exophily in An. gambiae, and to a lesser extent in An. funestus. With bifenthrin at high dosage, over 60% reduction in blood feeding and 75-90% mortality rates were observed in both vectors. Despite presence of holes, only a single An. gambiae and two An. funestus females were collected inside the treated net, and all were found dead. The same trends were observed with low dosage bifenthrin though in most cases, no significant difference was found with the untreated control net.
  
  
  CONCLUSIONS
  Bifenthrin-impregnated bednets at 50 mg/m2 were efficient in the reduction of human-vector contact in Pitoa. Considerable personal protection was gained against An. funestus and metabolic pyrethroid resistant An. gambiae populations.
authors.affiliation: Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale , Yaoundé, Cameroon. ms_chouaibou@yahoo.fr
authors.forename: Mouhamadou
authors.initials: M
authors.lastname: Chouaibou
authors.forename: Frédéric
authors.initials: F
authors.lastname: Simard
authors.forename: Fabrice
authors.initials: F
authors.lastname: Chandre
authors.forename: Josiane
authors.initials: J
authors.lastname: Etang
authors.forename: Frédéric
authors.initials: F
authors.lastname: Darriet
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Hougard
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D001512:Bedding and Linens / Q000469:parasitology*; D002163:Cameroon; D006801:Humans; D007303:Insect Vectors / Q000187:drug effects*; D007305:Insecticide Resistance; D007306:Insecticides / Q000008:administration & dosage*; D008288:Malaria / Q000517:prevention & control; D009032:Mosquito Control / Q000379:methods*; D011722:Pyrethrins / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D007306:Insecticides; D011722:Pyrethrins; C099952:bifenthrin