Control of pyrethroid‐resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

• Published in: Tropical medicine & international health 2009-04, Vol.14 (4), p.389-395
• Main Authors: N’Guessan, Raphael, Boko, Pelagie, Odjo, Abiba, Knols, Bart, Akogbeto, Martin, Rowland, Mark
• Format: Article
• Language: English
• Subjects: An. gambiae; Animal populations; Animals; Anopheles; Anopheles gambiae; bed nets; Bedding and Linens; bednets; Benin; Biological and medical sciences; Bénin; chlorphenapyr; clorfenapir; Comparative studies; Culex; Culex quinquefasciatus; culicidae; diptera; efficacy; experimental hut; General aspects; indoor residual spraying; Insecticide Resistance - drug effects; insecticide-treated nets; Insecticides; malaria; Malaria - prevention & control; Medical sciences; Mosquito Control - methods; Mosquitoes; moustiquaires; mutation; Pest control; pulvérisation; Pyrethrins; pyrethroid resistance; pyrrole insecticide; redes mosquiteras; Resistencia a piretroides; rociamiento residual intradomiciliario; résistance aux pyréthroïdes; Textiles; west-africa
• ISSN: 1360-2276; 1365-3156
• DOI: 10.1111/j.1365-3156.2009.02245.x

Summary Objective  To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method  Eight‐week trial conducted in experimental huts. Results  Indoor residual spraying killed 82.9% of An. gambiae overall (mean mortality: 79.5%) compared to 53.5% overall (mean mortality: 61.7%) in the hut containing the lower dosed ITN. Analysis of data on a fortnightly basis showed high levels of mosquito mortality and blood‐feeding inhibition during the first few weeks after treatment. Control of C. quinquefasciatus by the IRS and ITN interventions showed a similar trend to that of An. gambiae and though the average level of mortality was lower it was still much higher than with pyrethroid treatments against this population. Chlorfenapyr’s reputation for being rather slow acting was evident particularly at lower dosages. The treatments showed no evidence of excito‐repellent activity in this trial. Conclusion  Chlorfenapyr has the potential to control pyrethroid resistant populations of A. gambiae. There is a need to develop long‐lasting formulations of chlorfenapyr to prolong its residual life on nets and sprayed surfaces. On nets it could be combined with a contact irritant pyrethroid to give improved protection against mosquito biting while killing pyrethroid‐resistant mosquitoes that come into contact with the net. Objectif:  Comparer l’efficacité du chlorfenapyr appliqué sur des moustiquaires (MII) et comme pulvérisation résiduelle d’intérieur (IRS) contre les populations d’An. gambiae et de Culex quinquefasciatus dans une région du Bénin montrant des taux problématiques de résistance aux pyréthroïdes. Méthode:  Huit semaines d’essai sur des cases expérimentales. Résultats:  La pulvérisation résiduelle d’intérieur était plus efficace, tuant 82,9% d’An. gambiae par rapport à 53,5% de mortalité dans la case contenant la plus faible dose de MII. Le contrôle de C. quinquefasciatus par les interventions IRS et MII a montré une tendance similaire à celle de l’An. gambiae et quoique le taux moyen de mortalitéétait plus faible, il est encore beaucoup plus élevé que celui avec les traitements aux pyréthroïdes contre cette population. L’analyse des données sur une base bimensuelle a montré des taux élevés de mortalité des moustiques et une inhibition des piqûres durant les premières semaines après