Intramolluscan alterations of sporocysts induced by sublethal concentrations of Bauhinia monandra protein fraction in the Biomphalaria glabrata-Schistosoma mansoni interaction.

Schistosomiasis is a public health problem, and transmission of Schistosoma mansoni relying on snails of the genus Biomphalaria spp. Niclosamide is currently the molluscicide recommended by World Health Organization (WHO). However, its environmental toxicity and low selectivity raise concerns regarding ecosystem integrity. Plant-based compounds are promising alternative to molluscicides for controlling snails, including intermediate hosts of parasitic diseases. Previous study reports molluscicidal activity of Bauhinia monandra. We evaluated toxicological effects of sublethal concentrations of protein fraction from B. monandra leaves (LC25 [600 mg/L] and LC50 [870 mg/L]) on S. mansoni infected B. glabrata during sporocyst I and II developmental stages, in addition to its cytotoxic and genotoxic effects. Furthermore, we assessed the effects on S. mansoni miracidia and the ecotoxicity on Danio rerio. In infected snails, LC50 significantly reduced cercarial shedding, with mean cercariae counts of 49 ± 21.21 and 30 ± 15.37 compared to 143 ± 13.11 in the control group. Moreover, cercariae released from LC50 exhibited consistently low motility. Hemocyte analysis demonstrated morphological alterations, predominantly apoptosis and binucleation, and comet assay revealed genotoxic damage. Protein fraction reduced miracidia motility at 500 mg/L after 30 min, whereas 750 mg/L reduced motility within 15 min and caused miracidia mortality after 60 min. Infectivity assays revealed that miracidia exposed ≥ 750 mg/L failed to infect B. glabrata. No toxic effects were observed on D. rerio embryos. B. monandra fraction is an innovative molluscicide candidate based on ecological balance for B. glabrata population control and, consequently, for the control of schistosomiasis transmission.