Immunotoxical, neurotoxical, histopathological and immunohistopathological alterations of Nerium oleander and Tecoma stans methanolic extract on Biomphalaria alexandrina snails.

Schistosomiasis is a severe illness that caused socioeconomic problems. The present study aimed to investigate the molluscicidal activities of the methanolic extract of Nerium oleander and Tecoma stans on B. alexandrina snails. The present results showed that N. oleander had the higher molluscicidal effect (LC50: 138.6 mg/l) than T. stans methanolic extract (LC50: 256.0 mg/l). These concentrations had no mortality effects on Daphnia magna during the first 12 h of the exposure, while, they had a cercaricidal activity. Exposure of B. alexandrina snails to the sub lethal concentrations (LC10 and LC25) of the methanolic extract of either N. oleander or T. stans caused a concentration- dependent significant decrease in their mean total number of hemocyte and hyalinocytes percent, while, both the round small and the granulocytes were increased than the control group. Exposure of B. alexandrina snails to LC25 of the methanolic extract of N. oleander or T. stans, caused morphological alterations in the hemocytes that were studied by both light and electron microscopy. The sub lethal concentration (LC25) significantly decreased the acetyl cholinesterase activities, acid and alkaline phosphatase levels and the protein content. Histopathological changes occurred in the digestive and the hermaphrodite glands of exposed B. alexandrina snails to LC25 of the methanolic extracts. These alterations were confirmed by Immunohistochemistry for PCNA and Cyclin D1 expressions. Conclusively, these plants could be used to decrease the spread of schistosomiasis as they are cheap and environmentally safe to replace the synthetic molluscicides for snail control.

Hematological, physiological and genotoxicological effects of Match 5% EC insecticide on Biomphalaria alexandrina snails.

Freshwater snails are used as brilliant biomarkers of aquatic ecosystem pollution by chemical compounds. The objective of this study is to highlight the ecotoxicological impacts of the insecticide Match 5%EC (its active ingredient is lufenuron 5% EC) on Biomphalaria alexandrina snails the intermediate host of Schistosoma mansoni in Egypt. The present investigation recorded a remarkable molluscicidal effect of lufenuron 5% EC on these snails and there was a decrease in total number of their hemocytes after exposure. Three morphologically distinct populations of circulating hemocytes were identified (round small cells, granulocytes and hyalinocytes) and results showed that some hyalinocytes had a shrunk nucleus and some were degenerated. Significant increase of transaminases (ALT and AST), while, a decrease of the total protein and albumin content in hemolymph was recorded. The results of alkaline comet assay in the present study demonstrated that lufenuron 5% EC has a genotoxic effect especially when its concentration increases. It can be concluded that Biomphalaria alexandrina snails can be used as bio monitor to screen the deleterious effects of lufenuron 5% EC insecticide as a cause of the environmental pollution, and this insecticide can be used in controlling schistosomiasis because of its molluscicidal effects on B. alexandrina snails.