The Efficacy of Three Indigenous Plants (Tetrapleura tetraptera, Bridelia ferruginea and Azadirachta indica) as Plant Derived Molluscicides against Fresh Water Snails

Abstract

Schistosomiasis is a parasitic disease transmitted by fresh water snail infected with the Schistosoma parasites. The disease is endemic in many parts of Asia, Africa, and South America affecting people who are unable to avoid contact with water, either because of their profession or because of lack of reliable source of safe water for drinking, washing and bathing. The study focused on the molluscicidal activities of the oil extracts of Tetrapleura tetraptera, Bridelia ferruginea and Azadirachta indica on freshwater snails. The snails were collected from a stream at Ipogun village, which is about 14 km away from Akure. The collected snails were transferred into glass tank containing water in the laboratory, where they were fed with lettuce and left for 3-4 days to adjust to the laboratory conditions. The fruit, barks and leaves of T. tetraplura, B. ferruginea and A. indica respectively were air dried, pulverized into powder and the powders were soaked in 70% ethanol. The oils from the plant powders were extracted using Soxhlet machine and the bioassay was done at varying concentrations (0.4, 0.8, 1.2, 1.6, and 2.0 g/ml). Among all the plant extracts, Tetrapleura tetraptera showed the highest molluscicidal activity (100%) at 1.6 mg/l and 2.0 mg/l for 48 hours of exposure. Meanwhile, the lowest molluscicdal activity (10%) was found in Azadirachta indica at 8 hours of exposure. One-way Analysis of Variance of the result shows that there is significant difference in the molluscicidal activities of the three plant extracts (p < 0.05). It was also observed that the potency of the extracts increases as the concentrations and time of exposure increase. The results of this study show that the three plant extracts maybe used as veritable means of controlling schistosomiasis and other trematode infections.