Background: Schistosomiasis is a parasitic trematode-borne disease that can be acute or persistent. Its control focuses on reducing the disease through two main parallel roles: one of which is the curative role, such as using praziquantel in the periodic treatment of patients on a large population scale, and the other is the preventive role, such as applying biological control of snails that transmit the disease.
Aim: This study aims to evaluate the effect of bacterial metabolitesfrom Bacillus subtilis bacteria on Biomphalaria alexandrina snails as biological control agent as well as studying its effect on fecundity, sex hormones, histological changes and release of Schistosoma mansoni cercariea.
Material and Methods: B. alexandrina were exposed to secondary metabolites from B. subtilis (SMBS) at stated concentrations under suitable laboratory conditions.
Results: The results revealed that sublehal concentrations (ppm) were 93.66, 105.30, 118.23 and 142.79 for LC10, LC25, LC50 and LC90 respectively. Meanwhile, upon exposure for four successive weeks, significant reduction in the rate of egg laying capacity (fecundity) was observed according to the reduced levels of estradiol and testosterone. Also, significant reduction was observed in both infection rate and cercarial production. Eventually, lesion patterns were observed in the hermaphrodite glands upon investigating their histological sections at gradual bacterial metabolites concentrations.
Conclusion: metabolites of Bacillus subtilis has molluscicidal properties against Biomphlaria alexandrina snails. Consequently, it can aid at controlling of schistosomisis transmission.