Abstract

Background Spatial emanators disrupt mosquito behaviour by inducing movement away from chemical stimuli and interfering with host detection and feeding. These tools were recently endorsed by the World Health Organization (WHO) for malaria control, based largely on clinical evidence from East Africa. Mosquito ShieldTM is a passive, transfluthrin-based emanator designed to provide month-long protection in enclosed or semi-enclosed spaces. This study evaluated its entomological efficacy under experimental hut conditions in Benin, West Africa to generate evidence in support of WHO prequalification. Methods An experimental hut trial was conducted against wild free-flying pyrethroid-resistant Anopheles gambiae s.l. at the Covè field station in southern Benin over two 32-day product life cycles of Mosquito ShieldTM. Sixteen West African–style experimental huts were assigned to Mosquito ShieldTM or a placebo control. Efficacy was measured using human landing catches (HLC) and mosquito aspirations following standard hut testing methods. Primary endpoints included protective efficacy against mosquito landing (HLC) and personal protection against blood-feeding (mosquito aspiration). Secondary endpoints included deterrence, exophily, mortality, and blood-feeding inhibition. WHO susceptibility bioassays were conducted on the local An gambiae s.l. population to investigate susceptibility to public health insecticides during the trial.