Movement of Echinococcus granulosus under a light microscope

Echinococcosis, also known as hydatid cyst infection in humans and dwarf tape worm infection in dogs, is a zoonotic disease with a worldwide distribution. Echinococcosis is a significant health issue and carries commercial losses. It is caused by the metacestode stage of the dog tapeworm Echinococcus granulosus. This is a small worm, less than 1 cm long, that attaches to the intestinal villi. The life cycle of the genus Echinococcus involves two mammalian hosts. The definitive hosts are carnivorous dogs that become infected by ingestion of protoscoleces, consumed within the hydatid cyst as free brood capsules in contaminated meat, or within the tissue of the intermediate host.