Some people believe that ingesting a tapeworm will help with weight loss; one Iowa resident, who remains unidentified, ordered a tapeworm on the Internet and swallowed it as her diet strategy.
Tapeworm infections most commonly don't happen because you've eaten a tapeworm, though. Three species are responsible for human infections: Taenia saginata (beef tapeworm), Taenia solium (pork tapeworm) and Taenia asiatica (Asian tapeworm). Infections happen after cysticerci, the larval form of the parasite, are consumed accidentally while eating undercooked or raw beef or pork from a tapeworm-infected animal.
Tapeworms may cause gastrointestinal problems such as abdominal pain and upset stomach, as well as appetite changes and weight loss. For many, the infection is confirmed when tapeworm segments are visible in bowel movements — the stuff of nightmares. But it's Taenia solium that's associated with a more severe form of foodborne illness, cysticerosis. Cysticerosis causes focal neurologic deficit symptoms, headaches and visual disturbances, as well as localized striated muscle nodules and pain. More than 50 million people are infected with cycticerosis, making this tapeworm infection the most common parasitic infection around the world. Neurocysticerosis, when the tapeworm affects the neurological system, is the most common brain infection — plus it's the leading cause of adult-onset seizures [source: Kraft].
It takes two months for the cysticerci, the larval tapeworm, to develop into adulthood. Adult tapeworms may live in the small bowel of a human body for years. Taenia solium, for instance, may grow between 6.5 to 23 feet (2 to 7 meters) long, with as many as 1,000 segments, called proglottids, each containing 50,000 eggs within [source: Pearson].