Efficacy of Bendiocarb Used for Indoor Residual Spraying for Malaria Control in Madagascar: Results With Local Anopheles Species (Diptera: Culicidae) From Experimental Hut Trials

Abstract

To control malaria in Madagascar, two primary vector control interventions are being scaled up: insecticide-treated nets and indoor residual spraying of bendiocarb, which was implemented in the Malagasy Central Highlands in 2009. The current efficacy of bendiocarb against Anopheles species was evaluated in a small-scale field trial. An experimental hut trial comparing the effectiveness of bendiocarb sprayed on five substrates (cement, wood, tin, mud, and vegetative materials) was carried out against Anopheles species in two study sites located in the eastern foothills of Madagascar. No significant difference was detected in either exophily or blood-feeding rates between treated and untreated huts. The mortality rate was significantly greater in treated huts compared to untreated huts. Efficacy up to 80% was found for 5 mo posttreatment. Although effective, bendiocarb has been used for 7 yr, and therefore an alternative insecticide may be needed to avoid the emergence of resistance.

Efficacy of insecticides used in indoor residual spraying for malaria control: an experimental trial on various surfaces in a “test house”

“…Bendiocarb is an insecticide of the class of carbamates recommended by the WHO, with residual efficacy varying from 2 to 6 months [42]. The WP formulation achieved the expected residual efficacy on different surfaces [51, 74], but some studies reflected a short residuality from 2 to 3 months [51, 75–78].…”

Estimating the optimal interval between rounds of indoor residual spraying of insecticide using malaria incidence data from cohort studies

“…The same study showed that bendiocarb remains active for up to 20 weeks with 74% mortality for mosquitoes on mud compared to 100% for mosquitoes on thatch [ 11 ]. In Madagascar, bendiocarb was shown to have a mortality inducing effect on local mosquitoes of up to 80% for up to 5 months post spraying [ 12 ]. Elsewhere in Zanzibar, a study to investigate the residual effect of pirimiphos methyl active ingredient sprayed on common surfaces of human dwellings showed that its mortality inducing effect on local mosquitoes was maintained on all sprayed surfaces up to 8 months post-IRS [ 13 ].…”