Angiostrongylus cantonensis is a contained parasite worm in animals called rats. It is also called the rat lungworm. Rodents become a shelter for the mature (adult) form of the parasite and it is not found in human. Infected rats pass immature forms (larvae) of the parasite in their feces. Snails and slugs get infected by ingesting the larvae in rat feces. These larvae mature in snails and slugs but do not become adult worms. The life cycle comes full circle when rats eat infected snails or slugs and the larvae further mature to become adult worms.
Angiostrongylus cantonensi
If undercooked snails or slugs that are infected with this parasite eaten, people can get infected. For your information, in some cultures, snails are commonly eaten, some of people said that snails are chewy and tasty. Some children, in particular, have gotten infected by swallowing snails/slugs “on a dare.” People also can get infected by accident, by eating raw produce, such as lettuce, that contains a small snail or slug or part of one.
Reference
-http://www.cdc.gov/ncidod/dpd/parasites/angiostrongylus/factsht_angiostrongylus.htm
