Abstract

This study aims to detect the molluscicidal properties of the pesticides Basudin and Selecron and the phytoalkaloid Colchicine against Biomphalaria alexandrina snails including their infection withSchistosoma mansoni, production of cercariae, the levels of total protein, globulin and albumin and the activities of alanine and aspartate transaminases (AlT and AsT) and acid and alkaline phosphatases (AcP and AkP) enzymes in tissues of treated snails. The molluscicide Bayluscide was used as a reference compound. After 24 h of snails exposure to the tested compounds, Selecron was the most toxic one. Moreover, about 96% death rates of S. mansoni miracidia and cercariae was recorded after 45 min of exposure to the snails' LC_90s of Basudin and Selecron. In addition, infection rates of  snailswith S. mansoni and cercarial production were reduced post their exposure to  LC₁₀ and LC₂₅ of Basudin, Selecron and Bayluscide and to 100 and 250 ppm Colchicine either during or post snails exposure to miracidia. Thus, snails exposure to LC₂₅ of Selecron reduced cercarial production from 795.2 cercariae/control snail to 72.5 cercariae/infected treated snail. The results, also, revealed thattotal protein, globulin and albumin concentrations of treated snails were less than control group, while activities of the enzymes AsT, AlT and AkP were elevated. It is concluded that the tested compounds have deleterious effects on viability of S. mansoni miracidia and cercariae, the snails' biochemical parameters, their infection with this parasite and production of cercariae from infected snails. Then, accidental introduction of such chemicals to irrigation system during agricultural activities could negatively interrupt and/or prevent schistosomiasis transmission.

Key words: Pesticides, snails, Schistosoma mansoni, transaminases, phosphatases activities