The toxic effect of glycerol-Cu(II) counterions on the free-living stages of Aedes aegypti

Abstract

New insecticidal products are needed to control mosquito populations reducing vector-borne diseases (VBD). Ovicidal control is essential to disease control because the egg bank replaces the population at each reproductive cycle in breeding grounds. The use of carriers and bioactive metals has already been proposed. In the present work, toxic glycerol mixtures with Cu(II) counterions (acetate, chloride, nitrate, and sulfate) were tested in different combinations, showing toxicity against eggs and larvae of <italic>A. aegypti</italic>. Glycerol is an efficient Cu(II) transporter to the larval gut's intracellular environment. When using the glycerol-Cu(II) acetate, chloride, and nitrate samples, the larval incubation rate was greater than 95%, and the larval mortality rate ranged from 17% to 65%. The glycerol-Cu(II) sulfate was more toxic to eggs, and the sample glycerol-Cu(II) acetate was more toxic to the larvae among the tested counterions. The toxic action of Cu(II) would occur through the rupture and disintegration of the peritrophic matrix, permeation, formation of complexes, and the induction of oxidative stress in the region of the midgut (mesentery) of larvae and eggs of <italic>A. aegypti</italic> in alkaline pH. Using counterions may prevent the outbreak of mosquito populations in endemic areas, positively impacting regions that suffer from VBD.