Cyclophyllidea

an order of tapeworms. The Cyclophyllidea have four suckers on the head, and some also have a rostel-lum with hooks. They parasitize the intestines of the principal host, which may be any of a variety of vertebrates (excluding fishes) and is sometimes a human. The larvae parasitize the body cavity, muscles, and other organs of the intermediate host, which may be a vertebrate or arthropod. The transition from the larval to adult stage usually occurs as a result of a change of hosts.

The Cyclophyllidea cause serious diseases in humans and animals. Taenia solium parasitizes the human intestine. It measures 2–3 m in length, sometimes as much as 8 m. The larvae are oncospheres, which are enclosed in the mature segments of the tapeworm and are released with the host’s excrement. The larvae then enter the stomach of the intermediate host, for example, a pig, dog, or cat; they penetrate the blood vessels and settle mainly in the muscles, becoming bladder worms. Humans are infected by eating undercooked pork containing bladder worms.

Taeniarhynchus saginatus measures up to 10 m in length. Its intermediate host is cattle, and its definite host is man. Hymenolepis nana and Echinococcus granulosus are also dangerous parasites of humans.

All Cyclophyllidea severely emaciate the bodies of humans and animals and sometimes lead to their death. For control measures, see.