Combined Efficacy of Silver, Copper, and Hypochlorite Ions for Vector Control of Juvenile Aedes aegypti in Household Water Storage Containers

Abstract

This study evaluates the larvicidal effects of three common water disinfectants, silver (AgNO3), copper (CuSO4·5H2O), and hypochlorite (NaOCl) ions. The treatments were combined at 40–50% of their recommended drinking water guidelines and tested against late first instar and third instar Ae. aegypti larvae. The findings demonstrate that the combined application of water disinfectants yields greater efficacy in suppressing the emergence of Aedes aegypti compared to the use of the individual disinfectants alone. The silver (Ag) and copper (Cu) combination treatment (40 ppb Ag + 600 ppb Cu) showed the greatest efficacy, achieving nearly complete inhibition of emergence of the older instar larvae (98.52% [96.50, 99.47]). All treatments demonstrated high efficacy against late 1st instar Ae. aegypti larvae, with the combined copper and chlorine (Cl) treatment yielding the lowest survival rates, though individual disinfectants also produced substantial mortality. The results of this study provide critical insights to inform the design and implementation of point-of-use water treatment technologies for household water storage containers that both ensure safe drinking water and also strategically target mosquito breeding within household storage containers, thus supporting integrated vector management approaches essential for controlling neglected tropical diseases.