Taeniasis
Taeniasis is an intestinal infection caused by tapeworms from the genus Taenia, primarily the species T. saginata and T. solium. These tapeworms are commonly found worldwide, particularly in regions where cattle and pigs are raised. Humans become hosts for these parasites by consuming undercooked meat containing cysts from infected animals. Once inside the human intestine, the tapeworms can grow significantly, reaching lengths of up to twelve feet. While most cases of taeniasis are asymptomatic or cause only minor intestinal discomfort, complications can arise, especially with T. solium, which can lead to a more serious condition known as cysticercosis if the eggs are ingested. Cysticercosis can affect various body parts, including the brain and eyes, potentially resulting in severe health issues like seizures or blindness. Diagnosis typically involves examining feces for eggs or proglottids, while treatment usually includes medications such as praziquantel. Prevention strategies focus on proper meat cooking, good hygiene, and meat inspection to reduce the risk of infection.
Taeniasis
- ANATOMY OR SYSTEM AFFECTED: Digestive system, gastrointestinal system, intestines, stomach
- ALSO KNOWN AS: Beef tapeworm, cysticercosis, pork tapeworm
Definition
Taeniasis is an infestation by the tapeworm from the genus Taenia. Tapeworms are either of the species T. saginata or of the species T. solium, both of which can be found worldwide wherever cows and swine are raised.
Causes
Humans are final hosts for these worms, which enter the human body when a person eats undercooked meat from cows (T. saginata) or pigs (T. solium). The worms are present in the meat of a formerly infected animal in the form of cysts. In the human intestine, however, the tapeworms, after being ingested by a person, develop and grow up to twelve feet long. Both types of tapeworm grow into segments called proglottids that produce thousands of eggs. Eventually, proglottids break off and are passed from the host in feces. A second route of infestation comes from directly swallowing the eggs (because of one’s poor hygiene or because of contamination, including self-contamination, with the eggs of T. solium).
Risk Factors
Eating undercooked beef or pork is the most common risk factor in acquiring taeniasis. Other risk factors are eating food that has been handled by an infected person and having direct contact with an infected person.
Symptoms
Most taeniasis infestations produce no symptoms, other than minor intestinal distress. The infestation is usually discovered by seeing proglottids in the feces, particularly if the proglottids are moving. In rarer cases, swallowed T. solium eggs may move through the body to lodge in other areas, particularly the eye, heart, and central nervous system, including the brain. When this happens, the larvae form cysts that may provoke an immune response. This condition is known as cysticercosis, and it can be much more serious than intestinal taeniasis. Cysticercosis of the eye can cause blindness and neurocysticercosis, which affects the brain, can lead to seizures and death.
Screening and Diagnosis
Because tapeworm infestation usually has no symptoms, infection is generally detected by inspecting the feces for worm eggs, or proglottids. A complete blood count differential can also be done as confirmation. To detect cysticercosis, the doctor may order magnetic resonance imaging or a computed tomography scan.
Treatment and Therapy
The preferred drug for treating tapeworms is oral praziquantel. The drugs niclosamide and albendazole may also be used. With treatment, intestinal tapeworm infestations can be eliminated. If the larvae have moved into body tissues, however, treatment can be very difficult. In some severe cases, surgery may be needed to remove the cysts.
Prevention and Outcomes
Taeniasis infestations are best avoided through hygiene measures, including meat inspection, and beef and pork should be cooked at high enough temperatures to kill any potential eggs. Also, careful personal hygiene, including handwashing after bowel movements, can help to avoid spreading the disease.
Bibliography
Centers for Disease Control and Prevention. “Taeniasis.” Available at http://www.dpd.cdc.gov/dpdx/html/taeniasis.htm.
"Clinical Overview Taeniasis." Centers for Disease Control and Prevention (CDC), 3 May 2024, www.cdc.gov/taeniasis/hcp/clinical-overview/index.html. Accessed 4 Feb. 2025.
Icon Health. Tapeworms: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, Calif.: Author, 2004.
The Merck Manuals, Online Medical Library. "Taeniasis solium and Cysticercosis.” Available at http://www.merck.com/mmhe. Accessed 4 Feb. 2025.
Roberts, Larry S., and John Janovy, Jr. Gerald D. Schmidt and Larry S. Roberts’ Foundations of Parasitology. 8th ed. Boston: McGraw-Hill, 2009.
“Tapeworm Infestation.” In The American Medical Association Encyclopedia of Medicine, edited by Charles B. Clayman. New York: Random House, 1994.
“Taeniasis/Cysticercosis.” World Health Organization (WHO), 11 Jan. 2022, www.who.int/news-room/fact-sheets/detail/taeniasis-cysticercosis. Accessed 4 Feb. 2025.