Efficacy of a Mosaic Long-Lasting Insecticide Net, PermaNet 3.0, against Wild Populations ofCulex quinquefasciatusin Experimental Huts in Togo

Abstract

PermaNet 3.0 was evaluated againstCulex quinquefasciatusin experimental huts in Lomé. Endpoints were deterrence, exophily, blood feeding inhibition, and mortality. Insecticide susceptibility ofCulex quinquefasciatuswas assessed with permethrin (1%), DDT (4%), bendiocarb (0.1%), deltamethrin (0.5%, 0.05%), carbosulfan (0.4%), and chlorpyrifos methyl (0.4%). Total of 1,223Cx. quinquefasciatusfemales were collected. PermaNet 3.0 unwashed deterred 16.84%Culexmosquitoes. After 20 washes, it deterred 5.79% mosquitoes compared to 6.84% deterrence by unwashed PermaNet 2.0. PermaNet 3.0 induced mosquitoes to exit huts 50.48% and inhibited blood feeding 70.97% in unwashed state. After 20 washes, the net induced 42.91% mosquitoes to exit and inhibited 67.06% mosquitoes from blood feeding. PermaNet 3.0 gave 76% personal protection at zero wash and 69% protection after 20 washes. The net retained 7.1% insecticidal effect in the unwashed state and after 20 washes 6.5%.Cx. quinquefasciatuswas resistant to tested insecticides (6%–50% mortality). PermaNet 3.0 is a good control tool against mosquitoes. However,Cx. quinquefasciatusis less affected by PermaNet 3.0. The evaluation depicts the success of vector control innovations using pyrethroids and nonpyrethroids in combination on nets. Additional studies withCulexspecies are recommended to know whether the difference in blood feeding is interspecific (difference in vector behaviour) and not due to intertrial variability.