Delayed Impact of exposure to Royal Guard on pyrethroid-resistant malaria vectors.
The increasing pyrethroid resistance in malaria vectors underscores the need for control tools using non-pyrethroid molecules. This study assesses the efficacy of Alpha cypermethrin + pyriproxyfen, the dual active ingredient (ai) used in Royal Guard net, focusing on its long-term effects on mosquito life traits.
Cone tests showed low efficacy of Royal Guard on field populations of Anopheles. However, survival analysis indicated a reduced lifespan for exposed mosquitoes (7.9±0.2 days) compared to unexposed ones (11.4±0.4 days) (χ²=6; p=0.05). The net demonstrated a high blood-feeding inhibition rate (44%-80% vs 11%-41%) and significantly reduced oviposition (25%), fecundity (18.3%), offspring (8.1%), and increased infertility (74.74%) compared to controls. Resistance markers, including metabolic genes and L1014F-Kdrw, were linked to reduced net efficacy, with resistant mosquitoes more likely to survive (OR = 15.79; CI = 5.35-43.27; P < 0.0001).
Despite higher survival rates of pyrethroid-resistant mosquitoes after exposure to Royal Guard, the net significantly reduces their lifespan, blood-feeding ability, and reproductive capacity. Sonia Ngongang and collaborators therefore suggest that the National Malaria Control Programme (NMCP) should consider second-generation Long-lasting insecticidal nets (LLINs) such as Royal Guard for malaria control.
Read more: https://doi.org/10.1002/ps.8615
