title: Country-level operational implementation of the Global Plan for Insecticide Resistance Management.
abstract: Malaria control is reliant on the use of long-lasting pyrethroid-impregnated nets and/or indoor residual spraying (IRS) of insecticide. The rapid selection and spread of operationally significant pyrethroid resistance in African malaria vectors threatens our ability to sustain malaria control. Establishing whether resistance is operationally significant is technically challenging. Routine monitoring by bioassay is inadequate, and there are limited data linking resistance selection with changes in disease transmission. The default is to switch insecticides when resistance is detected, but limited insecticide options and resistance to multiple insecticides in numerous locations make this approach unsustainable. Detailed analysis of the resistance situation in Anopheles gambiae on Bioko Island after pyrethroid resistance was detected in this species in 2004, and the IRS program switched to carbamate bendiocarb, has now been undertaken. The pyrethroid resistance selected is a target-site knock-down resistance kdr-form, on a background of generally elevated metabolic activity, compared with insecticide-susceptible A. gambiae, but the major cytochrome P450-based metabolic pyrethroid resistance mechanisms are not present. The available evidence from bioassays and infection data suggests that the pyrethroid resistance mechanisms in Bioko malaria vectors are not operationally significant, and on this basis, a different, long-lasting pyrethroid formulation is now being reintroduced for IRS in a rotational insecticide resistance management program. This will allow control efforts to be sustained in a cost-effective manner while reducing the selection pressure for resistance to nonpyrethroid insecticides. The methods used provide a template for evidence-based insecticide resistance management by malaria control programs.
authors.affiliation: Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom. hemingway@liverpool.ac.uk
authors.forename: Janet
authors.initials: J
authors.lastname: Hemingway
authors.forename: John
authors.initials: J
authors.lastname: Vontas
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Poupardin
authors.forename: Jaishree
authors.initials: J
authors.lastname: Raman
authors.forename: Jo
authors.initials: J
authors.lastname: Lines
authors.forename: Chris
authors.initials: C
authors.lastname: Schwabe
authors.forename: Abrahan
authors.initials: A
authors.lastname: Matias
authors.forename: Immo
authors.initials: I
authors.lastname: Kleinschmidt
mesh_terms: D000818:Animals; D000852:Anopheles / Q000235:genetics*; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D016703:Equatorial Guinea; D006801:Humans; D007303:Insect Vectors / Q000235:genetics*; D007305:Insecticide Resistance / Q000235:genetics*; D062312:Islands; D008288:Malaria / Q000517:prevention & control*; D046228:Microarray Analysis; D009032:Mosquito Control / Q000379:methods*; D009570:Nitriles; D016133:Polymerase Chain Reaction; D011722:Pyrethrins; D013045:Species Specificity; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics
chemical_list: D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin; D040301:Vascular Endothelial Growth Factor Receptor-2