Epidemiological Survey of Snail Intermediate Hosts of Schistosomiasis in Zaria, Northwest Nigeria and Molluscicidal Screening of Ficus exasperata Extracts

Abstract

Schistosomiasis is a Snail-borne parasitic disease transmitted through water contact activities in endemic areas. It is associated with serious morbidities including anaemia, bladder cancer and infertility. Vector control efforts rely on the use of synthetic molluscicide (Niclosamide) which has been attributed to environmental toxicity. Snail intermediate hosts of schistosomiasis were obtained from water bodies and channels around Zaria, morphologically identified and screened for cercarial shedding. F. exasperata leaves and stem bark were obtained from natural habitat in Zaria, authenticated, dried under shade, ground into powder and subjected to extraction with distilled water, ethanol and methanol. The extracts were evaluated for phytochemical constituents, DPPH and FRAP radical scavenging activities and Molluscicidal efficacy against Bulinus spp. Higher percentage yield (8.62%) was obtained in Methanolic extract. Phytochemical analysis revealed the presence of compounds such as alkaloids, flavonoids, saponins, cardiac glycosides and steroids. Tannins and Phenolics have higher concentration compared to other phytochemicals detected in all the extracts. In vitro antioxidant analysis demonstrated moderate activity, with DPPH radical scavenging activity of 62%, 60% and 47% for methanolic, aqueous and ethanolic extracts, respectively. Molluscicidal screening of the extracts revealed dose dependent toxicity against Bulinus snails, with LC50 value of 23.59ppm, 28.96ppm, 31.51ppm for ethanolic, methanolic and aqueous extracts, respectively. These findings suggest that F. exasperata stem bark extracts could be exploited for development of eco-friendly botanical molluscicide. Further research is needed to identify the bioactive compounds responsible for Molluscicidal efficacy, elucidate the possible mechanisms of action, evaluate the efficacy in field trials and environmental impact.