Abstract
Snails act as intermediate hosts in trematode life cycles, and many studies have dealt with the question of how miracidia, mainly of schistosomes, find and recognize their snail hosts. However, the published results on the chemical snail host cues that attract miracidia of Schistosoma mansoni have been contradictory. Here, Wilfried Haas, Bernhard Haberl, Martin Kalbe and Martina Korner review data that indicate that macromolecular glycoproteins are the attractants, and that schistosome miracidia can distinguish between snail strains during their chemo-orientation towards the hosts. in echinostome life cycles gastropods also act as second intermediate hosts and are actively invaded by cercariae. However, these cercariae approach their snail hosts with types of chemo-orientation that differ from those of miracidia, and they respond to small molecular host cues.
