Opportunity or catastrophe? effect of sea salt on host-parasite survival and reproduction

Abstract

Seawater intrusion associated with decreasing groundwater levels and rising seawater levels may affect freshwater species and their parasites. While brackish water certainly impacts freshwater systems globally, its impact on disease transmission is largely unknown. This study examined the effect of artificial seawater on host-parasite interactions using a freshwater snail host, Biomphalaria alexandrina, and the human trematode parasite Schistosoma mansoni. To evaluate the impact of increasing salinity on disease transmission four variables were analyzed: snail survival, snail reproduction, infection prevalence, and the survival of the parasite infective stage (cercariae). We found a decrease in snail survival, snail egg mass production, and snail infection prevalence as salinity increases. However, cercarial survival peaked at an intermediate salinity value. Our results suggest that seawater intrusion into freshwaters has the potential to decrease schistosome transmission to humans.

A comprehensive exploration of schistosomiasis: Global impact, molecular characterization, drug discovery, artificial intelligence and future prospects

“…These snails are an essential part of the parasite's life cycle, and their presence is necessary for the successful transmission of schistosomiasis. Factors which influence hatching include temperature, light and salinity and freshwater provides the right environment for the eggs to hatch into the miracidium as well as for the miracidium to survive in the water [ 110 ].Studies have shown that water with high salt content is deadly to miracidia [ 109 , 111 , 112 ].…”