Efficacy of Metofluthrin Spatial Emanators to Reduce Human Vector Contact in Papua New Guinea.

Abstract

Alternative vector control tools are needed to address rising malaria burden in Papua New Guinea (PNG), where outdoor transmission and reduced insecticidal efficacy of insecticide-treated nets (ITNs) create persistent protection gaps. Volatile pyrethroid spatial emanators (SEs) release active ingredients that deter or kill mosquitoes, and 2 SE products have recently been WHO prequalified for malaria vector control. We evaluated the entomological efficacy of SumiOne™ SEs in 2 villages in PNG. Spatial emanators were installed indoors only or both indoors and outdoors in semi-enclosed peridomestic spaces, with 12 houses per intervention arm. Human landing catches and sentinel cage bioassays were conducted over 8 weeks and compared with a control arm. Human-vector contact was significantly reduced indoors, with a protective efficacy of 60%-80% in both intervention arms for 5-6 weeks, declining at approximately 6%-7% per week. No significant reduction in outdoor human-vector contact was detected. Indoor sentinel cage bioassays showed >80% 24-hour mortality for 7 weeks, and complete 60 minute knockdown and inhibition of probing for 8 weeks. SumiOne™ SEs substantially reduced indoor mosquito exposure and may complement ITNs for malaria control in PNG. Future research should prioritize increased longevity and stronger outdoor impact.