Snails as bio-indicators for dreaded trematodiasis diseases.

Snails (Mollusca : Gastropoda) are an ideal bio-indicators for palaeo-environments and water quality (pollution) and are much more useful in the classification of ecological diverse aquatic habitats.1-3 These aquatic snails also complete the life cycle of digenetic trematode parasites causing various dreaded trematodiasis diseases in vertebrates including men. Indeed these snails are an intermediate hosts of these highly pathogenic endoparasites and develop their larval stages (sporocysts, rediae, and cercariae). One of these larvae, “cercariae” are most active, non-feeding, and free swimming stage and become infective in some cases, otherwise these further undergo another infective stage, “metacercariae”.