A low-cost house eave screening technique complements insecticide-treated nets in reducing indoor human exposure to the bites of anopheles mosquitoes in a malaria endemic area of south forested Cameroon: results from a pilot study

Abstract

Currents insecticide-based vector control strategies are struggling to reduce malaria transmission. This pilot study investigated the potential of a low-cost eave screening technique to reduce human exposure to malaria vectors in a forested area of Cameroon. The pre-intervention phase consisted of collecting baseline data on malaria epidemiology including the human malaria prevalence, vector biology and the bio-efficacy of insecticide-treated nets (ITNs). During the intervention phase, selected houses were improved by screening open eaves with wire insect mesh stapled to wood lathe strips that were attached to the exterior walls. Neighbouring unscreened houses were used as the control. In the post-intervention phase, entomological parameters of malaria transmission were assessed again and compared between improved and unimproved houses. In addition, the cost, community perceptions and the durability of the intervention were evaluated. Prior to the intervention, the prevalence of malaria in human was 38.85 %, while the entomological inoculation rate (EIR) was 73 infected bites per person per year (ib/p/y). Anopheles gambiae s.l. was the major local vector and was full susceptible to pirimiphos-methyl but resistant to bendiocarb and pyrethroids insecticides. The possession and use ITNs were 89.62 % and 79 %, respectively. Only the pyrethroid + PBO ITNs were effective against the local An. gambiae s.l. population. The intervention led to a 5.5-fold reduction in the EIR in improved houses (from 37.70 to 6.90 ib/p/y), was cost-effective ($23.6 spent per modified house) and was highly appreciated by community beneficiaries since it improved their wellbeing. This pilot study employed a low-cost house improvement technique that can be integrated with other vector control strategies in malaria endemic areas.