Tapeworms live as parasites in the gastrointestinal tract. Some organisms primarily infect humans, while others normally infect animals but can also cause disease in humans. They are found worldwide and, although most cause only mild disease, some infections can have serious complications.
Taeniasis and Cysticercosis
Taeniasis arises after ingestion of meat infected with the beef tapeworm, Taenia saginata, or the pork tapeworm, Taenia solium. It occurs worldwide, often in areas where people eat raw or undercooked pork or beef. The World Health Organization reports, however, that taeniasis has become less common in places with stricter meat inspection and improved sanitation.
Most people with taeniasis have no symptoms, and some only suspect it after finding worm segments in their stool. Other symptoms include abdominal pain and loss of appetite.
Taenia solium cysts can develop in other parts of the body, mainly in the central nervous system. This leads to a more serious disease called cysticercosis. Symptoms include seizures, headaches, and mental disturbances.
Echinococcosis
The most common forms of echinococcosis are cystic, caused by Echinococcus granulosus, and alveolar, caused by Echinococcus multilocularis. Infection occurs by eating food contaminated with animal feces or by handling infected animals, usually cats or dogs.
People with Echinococcus granulosus can have no symptoms for years until the cysts grow big enough to affect the organ they inhabit. Cysts in the liver may cause abdominal pain or mass, while those in the lungs can cause chest pain and cough. Echinococcus multilocularis affects the liver, causing increased liver size, abdominal pain and weight loss. Echinococcosis can lead to death if left untreated.
Diphyllobothriasis (Fish Tapeworm)
Diphyllobothrium latum, the largest human tapeworm, is the most common cause of diphyllobothriasis. According to the Centers for Disease Control and Prevention, or CDC, adult worms can reach lengths over 30 feet.
Many freshwater fish can transmit diphyllobothriasis. Eating raw or undercooked fish and shellfish increases the risk of infection.
Majority of infected people have no symptoms, but some report abdominal discomfort, diarrhea, vomiting, and weight loss. Anemia may also occur.
Hymenolepiasis (Dwarf Tapeworm)
The CDC reports that hymenolepiasis is the most commonly diagnosed tapeworm infection in the United States and worldwide. The disease usually occurs in areas with poor sanitation and hygiene, often affecting children and institutionalized persons. Infection occurs by ingestion of eggs of the dwarf tapeworm, Hymenolepis nana. These may exist in food, water or soil contaminated with feces.
Most people with hymenolepiasis do not have symptoms. More severe infections can cause weakness, abdominal pain, diarrhea and loss of appetite. Nausea, dizziness, and irritability may also occur.
Treatment
Tapeworm diseases can be passed on from person to person, so consult your health care provider for immediate diagnosis and treatment if you suspect a tapeworm infection.
The drug of choice for treating tapeworm infections, except echinococcosis, is Praziquantel. Treatment of cysticercosis may require the additional use of an anti-inflammatory drug, such as a corticosteroid. Echinococcosis treatment usually involves surgical removal of the cysts and use of an antiparasitic drug, such as Albendazole.
