A preliminary test of the protective efficacy of permethrin-treated bed nets in an area of Anopheles gambiae metabolic resistance to pyrethroids in north Cameroon

A trial of permethrin-treated nets (PTNs) versus untreated nets (UTNs) was conducted in Pitoa (north Cameroon), where the main malaria vectors, Anopheles gambiae s.l. and Anopheles arabiensis, show metabolic-based permethrin resistance. The deterrent effect of permethrin greatly reduced A. gambiae biting rate inside rooms where PTNs were installed. After 3 months of net use, malaria reinfection rate was significantly lower in children sleeping under a PTN, but no such effect was observed after 6 months. Parasitaemia was not significantly different between the two arms. These findings suggest good, although transitory, personal protection against malaria conferred by PTNs in an area of metabolic-based permethrin resistance.