The third snail host, prevalent in Formosa and the Philippines, has a limestone trap door inside its shell that mangles the attacking larva. No Taste for Babies.

Hatched in fresh water, the schistosomal larva must invade a snail within about 24 hours or die. After weeks of development and change in the snail, ...

The findings indicated that 13% of stressed snails released larvae, compared to none in a non-stressed control group. Rat lungworm is a parasite with a development that cycles between snails and rats.