Spirometra erinaceieuropaei is a tapeworm that infects domestic animals and humans. In humans infection is called sparganosis. The worm has an interesting lifecycle, the adult worm is present in the small intestine of cats and dogs where it may grow as long as 1.5 metres. Eggs from the worm are passed with the host feces, when they develop into a proceroid larva. This larva may be directly ingested by humans or may enter an intermediate host which include frogs, birds, snakes, rats and mice and become a plerocercoid larva. When cats, dogs, foxes or wolves eat the intermediate host the worm completes its life cycle becoming an egg producing adult. Because humans would normally ingest the worm at the proceroid stage the human is a dead-end host.
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