Human taeniasis is a parasitic infection caused by three tapeworm species, T. saginata (known as the beef tapeworm), T. solium (pork tapeworm), and T. asiatica (the Asian tapeworm). Humans are the only hosts for these Taenia tapeworms. Humans pass the tapeworm segments and/or eggs in feces and contaminate the soil in areas where sanitation is poor. Taenia eggs can survive in a moist environment and remain infective for days to months. Cows and pigs become infected after feeding in areas that are contaminated with Taenia eggs from human feces. Once inside the cow or pig, the Taenia eggs hatch in the animal’s intestine and migrate to striated muscle to develop into cysticerci, causing a disease known as cysticercosis. Cysticerci can survive for several years in animal muscle. Humans become infected with tapeworms when they eat raw or undercooked beef or pork containing infective cysticerci. Once inside humans, Taenia cysticerci migrate to the small intestine and mature to adult tapeworms, which produce segments and eggs that are passed in feces.
Most people with tapeworm infections have no symptoms or mild symptoms. Patients with T. saginata taeniasis often experience more symptoms that those with T. solium because the T. saginata tapeworm is larger in size (up to 10 meters (m)) than T. solium (usually 3 m). Tapeworms can cause digestive problems including abdominal pain, loss of appetite, weight loss, and upset stomach. The most visible symptom of taeniasis is the active passing of proglottids (tapeworm segments) through the anus and in the feces. In rare cases, tapeworm segments become lodged in the appendix, or the bile and pancreatic ducts.
Infection with T. solium tapeworms can result in human cysticercosis, which can be a very serious disease that can cause seizures and muscle or eye damage.
More on: cysticercosis
Taenia saginata does not cause cysticercosis in humans. It is not clear if T. asiatica causes cysticercosis in humans or not.