Beef tapeworm

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Taenia saginata, also known as Taeniarhynchus saginata or the Beef tapeworm, is a parasite of both cattle and humans, but which can only reproduce in humans. T. saginata occurs where cattle is raised, human feces is improperly disposed of, meat inspection programs are poor, and where meat is eaten without proper cooking. The disease is relatively common in Africa, some parts of eastern Europe, the Philippines, Mexico, and Latin America. Undercooked meat from small farms in the United States may also be infected. Proglottids full of eggs are passed with human fecal matter and then eaten by cattle. Oncosphere larvae hatch in the small intestine of the bovid and then travel through the blood to muscle tissue and form "bladder worms," which are larval stages called cysticerci (singular cysticercus). Cysticerci are infectious to humans that eat them.

Like all cyclophyllid cestodes, T. saginata has four suckers on its scolex, but unlike the closely related Taenia solium, it has no other structures there.

The eggs look like other eggs from the family Taeniidae, so it is only possible to identify the eggs to the family, not to the species, level. On the other hand, proglottids sometimes trickle down the thighs of infected humans and are visible with unaided eye and aid with identification. When the uterus is injected with India ink, its branches become visible. Counting the uterine branches enables some identification (T. saginata uteri have twelve or more branches on each side, while other species like T. solium only have five to ten).

Symptoms include a loss of appetite or feeling of fullness, nausea, vomiting, diarrhea. Niclosamide, used to treat many different kinds of infections with trematodes and adult tapeworms, is the best drug. Proper disposal of feces, and making sure that all meat has been cooked properly helps prevent the spread of disease. In Western societies, meat is inspected for parasites. Additionally, freezing the meat at -10^oC for five days kills any worms and larvae.