Effectiveness of Permanet in Côte d’Ivoire Rural Areas and Residual Activity on a Knockdown-Resistant Strain of Anopheles gambiae

Abstract The effectiveness of long-lasting preimpregnated nets of Permanet type (deltamethrin, 50 mg/m2) erected in households in rural areas of Cote d’Ivoire was tested on two laboratory strains of Anopheles gambiae s.s.: the Kisumu susceptible strain and the Vk per pyrethroids resistant strain with >70% kdr allelic frequency. Treated nets were distributed in households in three villages of Danane forest area in western part of Cote d’Ivoire. In each village, a net was sampled for bioassays. Three Permanets also were erected in the laboratory, serving as control samples. From May 2001 to July 2002, the effectiveness of these deltamethrin-pretreated nets was monitored using World Health Organization-cone tests on the two strains of An. gambiae. Mortality rates were recorded 24 h postexposure. Knockdown times for 50 and 95% mosquitoes (kdT50 and kdT95, respectively) were estimated by means of WIN DL software. One-way analysis of variance was used to compare the knockdown times. Times to failure of nets wer...