Multimodal platform for ITN efficacy: Surface chemistry, bioavailability, and mosquito behavior.

Abstract

Insecticide-treated nets (ITNs) are crucial for malaria control, but their efficacy is compromised by rising mosquito resistance. To better understand ITN effectiveness, we present a multidisciplinary framework through a case study examining the removal of per- and polyfluoroalkyl substances (PFAS) from ITN coatings and its impact on malaria vectors in East and West Africa. Our results show that PFAS-free pyrethroid nets exhibit reduced bio-efficacy against resistant malaria vectors compared with PFAS-based nets, despite both meeting deltamethrin specifications. Surface characterization reveals that PFAS stabilizes smaller, noncrystalline deltamethrin particulates enhancing bioavailability, while PFAS-free coatings promote particulate aggregation with an increased population of crystalline deltamethrin. Behavioral assays suggest that PFAS-free formulations reduce mosquito contact time and insecticide uptake, with resistant strains showing decreased irritancy and knockdown. These findings highlight the trade-offs of PFAS removal and stress the need for a multidisciplinary approach combining advanced chemical analytics and behavioral assessments to optimize ITNs for effective malaria control while considering environmental sustainability.