Versatile natural molluscicides against the snail Biomphalaria glabrata Say, 1818 (Pulmonata: Planorbidae), the principal vector of Schistosoma mansoni on the american continent

Abstract

Schistosomiasis is a millennium-old disease that affects approximately 235 million people. Considering that most of the population affected by schistosomiasis faces varying levels of poverty, finding plant-derived compounds that can help control or eradicate this disease would be worthwhile, especially if the plants are readily available to those who need them most. This study aimed to evaluate the effects of fresh latex from fourteen locally cultivated Euphorbiaceae species on the freshwater snail Biomphalaria glabrata Say, 1818 (Gastropoda: Planorbidae), the principal vector of the Schistosoma mansoni trematode on the American continent. Adult B. glabrata snails were exposed to various concentrations of fresh latex from Euphorbiaceae species for 24 and 48 hours. Mortality data were analyzed using the probit method. To evaluate the latex ecotoxicity of the promising species against other aquatic organisms, lethality tests were performed on Poecilia reticulata Peter, 1859 (Cyprinodontiformes: Poeciliidae) fish and Artemia salina Leach (Anostraca: Artemiidae) nauplii. Three species exhibited significant molluscicidal activity: Euphorbia milii var. breonii (LC50 = 0.9 µg/mL), E. milii var. milii (LC50 = 1.1 µg/mL), and E. umbellata (LC50 = 9.1 µg/mL). Only E. milii (var. breonii and var. milii) were not lethal to the evaluated fish (LC50 of 9.9 µg/mL) and to A. salina (LC50 > 100.0 µg/mL). These results qualify both the E. milii variety of fresh latices as versatile (active at low concentrations, biodegradable, inexpensive, and obtained from renewable resources) and alternative molluscicidal agents against B. glabrata snails.