Evaluation of indoor residual spraying with the pyrrole insecticide chlorfenapyr against pyrethroid-susceptible Anopheles arabiensis and pyrethroid-resistant Culex quinquefasciatus mosquitoes
Transactions of the Royal Society of Tropical Medicine and Hygiene
Kilimanjaro Christian Medical College of Tumaini University, P.O. Box 2240, Moshi, Tanzania; London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, United Kingdom; Pan-African Malaria Vector Research Consortium (PAMVERC), United Kingdom; Centre de Recherches Entomologique de Cotonou (CREC), Cotonou, Benin
Chlorfenapyr is a pyrrole insecticide with a unique non-neurological mode of action. Laboratory bioassays of chlorfenapyr comparing the mortality of pyrethroid-susceptible and -resistant Anopheles gambiae s.s. and Culex quinquefasciatus mosquitoes indicated that operational cross-resistance is unlikely to occur (resistance ratio ranged between 0 and 2.1). Three trials of chlorfenapyr indoor residual spraying were undertaken in experimental huts in an area of rice irrigation in northern Tanzania that supports breeding of A. arabiensis. Daily mosquito collections were undertaken to assess product performance primarily in terms of mortality. In the second trial, 250mg/m2 and 500mg/m2 chlorfenapyr were tested for residual efficacy over 6 months. Both dosages killed 54% of C. quinquefasciatus, whilst for A. arabiensis 250mg/m2 killed 48% compared with 41% for 500mg/m2; mortality was as high at the end of the trial as at the beginning. In the third trial, 250mg/m2 chlorfenapyr was compared with the pyrethroid alpha-cypermethrin dosed at 30mg/m2. Chlorfenapyr performance was equivalent to the pyrethroid against A. arabiensis, with both insecticides killing 50% of mosquitoes. Chlorfenapyr killed a significantly higher proportion of pyrethroid-resistant C. quinquefasciatus (56%) compared with alpha-cypermethrin (17%). Chlorfenapyr has the potential to be an important addition to the limited arsenal of public health insecticides for indoor residual control of A. arabiensis and pyrethroid-resistant species of mosquito. © 2010 Royal Society of Tropical Medicine and Hygiene.
chlorfenapyr; pyrethroid; pyrrole; unclassified drug; Anopheles arabiensis; article; breeding; cross resistance; Culex quinquefasciatus; insect control; insect resistance; insecticidal activity; insecticide resistance; nonhuman; pesticide spraying; Animals; Anopheles; Bedding and Linens; Culex; Housing; Insecticide Resistance; Insecticides; Malaria; Mosquito Control; Pesticide Residues; Pyrethrins; Tanzania; Anopheles arabiensis; Anopheles gambiae; Culex pipiens quinquefasciatus