Effects of Water Pressure on Viability and Infectivity of Schistosoma mansoni Cercariae

Abstract Background Schistosomiasis remains a significant public health concern, currently infecting over 240 million people globally, with an additional 600 million individuals at risk. The bulk of these cases are concentrated within Sub-Saharan Africa. Despite widespread implementation of Multi Drug Administration (MDA) programmes using Praziquantel, transmission persists due to the drug's inability to kill immature schistosomes and high rates of reinfection from contaminated freshwater sources. This study sought to explore the effects of water pressure on the viability and infectivity of Schistosoma mansoni cercariae in Nyakach Sub County, Kisumu County, Kenya. Methodology The study employed a three-phase experimental design: A malacological survey along the Asawo stream to establish intermediate host abundance, in vitro assays to quantify the impact of varying hydrostatic pressure levels on cercarial survival, and in vivo assessments using Swiss albino mice to measure post-pressure infectivity. Results Results from the malacological survey identified Biomphalaria pfeifferi as the main vector, with a significantly higher abundance in stagnant pools (mean = 43.0) compared to flowing stream sites (mean = 16.8) (p < 0.01). Laboratory assays revealed that hydrostatic pressure serves as a potent mechanical disinfectant; exposure to 40 bar of pressure resulted in a 98.0% mortality rate, while in vitro testing at 20 kg/cm² achieved a log 10 reduction of > 2.0 within 180 minutes. Microscopic analysis demonstrated extensive morphological trauma. In vivo results further confirmed the efficacy of high pressure, as mice exposed to cercariae treated at 40 bar exhibited zero adult worm recovery. Pumping experiments through a 0.5-inch pipe at 12,000 psi achieved a 98.8% reduction in worm burden and a near-total cessation of egg excretion. Conclusions These findings indicate that high hydrostatic pressure provides an effective physical intervention for neutralising S. mansoni in closed water systems such as pipelines, aquaculture systems and swimming pools. This offers a critical technological complement to therapeutic measures in the pursuit for schistosomiasis elimination.