Performance of different spatial repellents (spatial emanators) against vector mosquito species in Mali, West Africa: a field trial using a non-human test method.

Introduction: Spatial repellents (also called spatial emanators) are widely marketed for personal protection against mosquito bites, yet their real‑world performance varies substantially and is rarely evaluated under standardized field conditions. This study quantified the protective efficacy of six consumer‑available repellent devices at paired urban ( Methods: Products included a Dynatrap® Mosquito Repellent electronic device with an 8.83% transfluthrin-containing replaceable heat-activated cartridge, a Thermacell Results: Across both sites, the heat-activated volatile pyrethroid devices achieved the strongest and most consistent reductions in mosquito captures. At the urban site, the Dynatrap Discussion: Together, these results demonstrate that heat‑activated volatile pyrethroid devices can deliver strong, broad‑spectrum spatial protection across ecologically varied environments. The study emphasizes the need for standardized, wind‑controlled field testing and highlights significant performance gaps among widely marketed consumer repellents. Given that spatial repellents are now formally recognized as a recommended intervention class in the 2025 WHO Guidelines, these performance gaps carry important public health implications, as inconsistent or underperforming products could undermine the protective value expected from this intervention category.