Evaluation of the pyrrole insecticide chlorfenapyr against pyrethroid resistant and susceptible Anopheles funestus (Diptera: Culicidae)
Tropical Medicine and International Health
Vector Control Reference Unit, National Institute for Communicable Diseases, NHLS, Private Bag X4, Sandringham 2131, South Africa; Malaria Entomology Research Unit, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa; NRF Department of Medical Entomology and Vector Control, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa; London School of Hygiene and Tropical Medicine, London, United Kingdom
Objective To evaluate the pyrrole insecticide chlorfenapyr, which has a novel non-neurotoxic mode of action and is a promising alternative to conventional adulticides, against Anopheles funestus. Method The toxicity of a range of concentrations of chlorfenapyr against pyrethroid resistant and susceptible laboratory reared southern African An. funestus was assessed using standard WHO protocols and analysed using probit analysis. Results The pyrethroid resistant strain showed consistently higher LD50 and LD95 values compared to the susceptible strain, but these differences were not statistically significant and the magnitude was twofold at most. The LD50 values recorded for An. funestus are approximately three-fold higher than those reported elsewhere for other species of anopheline. Conclusions Monooxygenase based pyrethroid resistance in An. funestus does not influence the toxic effect of chlorfenapyr. It is unlikely that such a small decrease in susceptibility of An. funestus to chlorfenapyr relative to other anophelines would have any operational implications. Chlorfenapyr is an important addition to insecticides available for malaria vector control, and could be used as a resistance management tool to either circumvent or slow the development of resistance. © 2009 Blackwell Publishing Ltd.
insecticide; pyrethroid; pyrrole derivative; unspecific monooxygenase; chemical control; disease control; disease vector; enzyme activity; insecticide; malaria; mosquito; pesticide resistance; resistance management; toxicity; World Health Organization; Anopheles; anopheles funestus; article; controlled study; genetic strain; insecticidal activity; insecticide resistance; LD 50; malaria; malaria control; nonhuman; resistance management; South Africa; toxicity; vector control; world health organization; Animals; Anopheles; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Insect Vectors; Insecticide Resistance; Insecticides; Lethal Dose 50; Pyrethrins; Survival Analysis; Africa; Anopheles funestus; Culicidae; Diptera