Biocontrol of snail-borne parasites with the glossiphoniid leech, Helobdella austinensis

Abstract

Parasites in which freshwater snails are intermediate hosts pose a serious threat to human health worldwide. We show here that freshwater snails can potentially be controlled by leech predation; in principle, this approach could significantly reduce snail-borne parasitic diseases (SBPDs). Specifically, glossiphoniid leeches, Helobdella austinensis and congener species, consume freshwater snails indiscriminately, while other common leeches do not. A single adult H. austenensis, for example, can consume up to its weight in snails, e.g. Physella acuta, per day. Our predator–prey models suggest that snail populations could be eliminated in relatively short time periods (approximately six months) using a leech biocontrol approach. This could have considerable impact on global SBPDs by breaking the intermediate host life cycle.