Efficacy of Transfluthrin Varies by Species and Placement in a Warm Temperate Mediterranean Environment1

Abstract

Spatial repellents may protect personnel in delimited areas from incursion of vector or nuisance Diptera, such as mosquitoes and sand flies. We investigated the efficacy of resin diffusers impregnated with transfluthrin in protecting 2 simulated military field scenarios (partially opened tents and open bivouacs lacking shelter) from natural populations of Culex species mosquitoes and Phlebotomus species sand flies. Using a benchmark efficacy of 61% expected reduction from a recent literature survey, we found that transfluthrin protected bivouacs from sand flies (74.1% average reduction; P < 0.001, t(38) = 4.234) but not mosquitoes (13.1% mean reduction, not significant). However, treated tents were not sufficiently protected from sand flies (33.3% mean reduction, not significant), and mosquito numbers increased by an average of 89.3% (not significant). Spatial repellents such as transfluthrin can be highly effective, but efficacy may vary by species and placement, and they should be incorporated into integrated vector management with care.