Tapeworms are large, flat parasitic worms that live in the intestinal tracts of some animals. They are passed to humans who consume foods or water contaminated with tapeworm eggs or larvae.
Six types of tapeworms are known to infect humans, usually identified by their source of infestation: beef, pork, dog, rodent, fish, and dwarf (named because it is small).
There are often no symptoms as tapeworms grow in humans. Untreated cases can be life-threatening or lead to permanent tissue damage, but tapeworm infections confined to the intestines can easily be treated with medication.
Tapeworm infection in people usually results from eating undercooked foods from infected animals. Pigs or cattle, for example, become infected when grazing in pastures or drinking contaminated water.
The parasites mature in the animal’s intestines to pea-shaped larvae, and are transmitted to people who eat pork or beef. In addition, tapeworms can also be passed from hand-to-mouth contact, if you touch a contaminated surface and then touch your mouth.
The following factors increase your chances of developing tapeworm infection. If you have any of these risk factors, tell your doctor:
- Eating raw or undercooked meats.
- Poor hygiene. Not washing often can increase the risk of transferring tapeworm parasite from hand-to-mouth.
- Exposure to livestock, particularly in areas where human and animal feces are not properly disposed.
- Travel to underdeveloped countries with poor sanitary conditions.
If you experience any of these symptoms do not assume it is because you have a tapeworm. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician.
- Abdominal pain
- Hunger or loss of appetite
- Weight loss
You may be able to self-diagnose tapeworm infection by checking your stool for signs of tapeworms. But more likely, if you suspect infection, see your doctor, who will ask about your symptoms and medical history, and perform a physical exam. Tests may include the following:
- A stool sample that will be sent to a laboratory for analysis. Sometimes, several samples are needed over a designated period, since tapeworm eggs and segments may be released irregularly in human stool.
- A blood test to indicate the presence of antibodies produced to fight tapeworm infection
- A CT or MRI scan—a type of x-ray that uses computers (CT) and magnetic waves (MRI) to make pictures of structures inside the body. These scans may be needed for serious cases in which the parasite might have infected other areas of your body beside the digestive tract.
Tapeworm infection is treated with oral medication. Commonly used drugs include:
- Biltricide (praziquantel)
- Albenza (albendazole)
These medications work by dissolving or attacking the adult tapeworm, but may not target eggs. Proper hygiene is essential to avoid re-infection; always wash your hands before eating or after going to the bathroom.
Your doctor will check stool samples at one and three months after you've finished taking your medication. The success rate is greater than 95% in patients who receive appropriate treatment.
To help reduce your chances of getting a tapeworm infection, take the following steps:
- Wash your hands with soap and hot water before eating or handling food
- Wash after using the toilet.
- Freezing meat or fish for varying lengths of time can kill tapeworm eggs or larvae.
- Thoroughly cook meat at temperatures of at least 150 degrees F; avoid raw fish.
- When traveling in undeveloped countries, wash and cook all fruits and vegetables with safe water before eating.
- Get prompt treatment for pets infected with tapeworm.
American Veterinary Medical Association (AVMA)
The Centers for Disease Control and Prevention
The World Health Organization
British Columbia Centre for Disease Control
University of British Columbia Centre for Disease Control
Beers MH, Berkow R.
The Merck Manual of Medical Information (online edition).
Whitehouse Station, NJ: Merck Research Laboratories; 2004.
Available at: http://www.merck.com/mmhe/sec17/ch196/ch196k.html. Accessed Oct. 29, 2006.
Klag MJ (editor-in-chief). The Johns Hopkins Family Health Book. Baltimore, MD: HarperCollins Publishers; 1999.
Parasitic diseases. The US Library of Medicine website. Available at:
http://www.nlm.nih.gov/medlineplus/print/parasiticdiseases.html. Accessed Oct. 29, 2006.
Last reviewed November 2008 by David L. Horn, MD, FACP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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