Comparative Efficacies of Different Bed net Fabrics
Impregnated with Permethrin Against Culex pipiens quinquefasciatus Say. Part I – Knockdown/Mortalities on
Different Netting Fabrics
MOLTA, N.B., DAVID, P.S. and ONYEKA, J.O.A.
ABSTRACT: The efficacies of permethrin-impregnated cotton, nylon and polyethylene fabrics were assessed against Culex pipiens quinquefasciatus Say in the laboratory in Jos, Plateau State, Nigeria. Adult females were exposed to treated surfaces of these common bed-net fabrics in standard exposure tubes of the World Health Organization (WHO). Knockdown (KD) and mortalities of the mosquitoes, recorded at 5 minutes intervals over a total exposure period of 60 minutes, commenced rapidly within the first 5 minutes of
exposure. The overall responses are represented by the following regression equations: a) cotton, y= 5.81x -2.03; b) nylon, y= 5.97x – 2.17 and c) polyethylene, y= 6.l1x – 2,5l. From these equations, the time taken to knock down 50% of the mosquitoes (i.e. KDTso) are estimated to be 16 minutes 12 seconds for cotton; 15 minutes 53 seconds for nylon and 17 minutes for polyethylene. However, there were no significant differences (X2 =
0.040, df= 2, p> 0.05) between the KDTso values obtained with the different netting fabrics. These results suggest that the different fabrics are essentially similar in efficacy and could be used interchangeably in the impregnated bed-nets intervention programme,
at least against Cx. quinquefasciatus.