Tapeworm Infection Unusual in the US

Q:  I heard that millions of people have tapeworms and don't know it. How would you know if you have a tapeworm and how can you get rid of it if you do?

Can you pass tapeworms to others?

A:  There are about a half-dozen different kinds of tapeworms that can affect humans, and in many parts of the world, tapeworm infection is indeed common. For example, the pork tapeworm is common in areas of the world (i.e., Latin America, Africa, the Middle East and Central Asia) where people frequently eat undercooked pork, sanitation is poor, and pigs roam free to ingest the contaminated water.

Tapeworms are parasites, which means they require another animal to live and reproduce. Most tapeworms need a couple of different species to complete their life cycle. For example, the pork tapeworm needs both a pig to allow eggs to grow into embryos and a human to allow embryos to grow into adults that make more tapeworm eggs.

However, the dwarf tapeworm, called so because it is smaller than other tapeworms at 1 to 1-1/2 inches long, can be passed from person to person by any contact with the stool of an infection person. (This is one of the many reasons health care professionals cite the importance of washing one's hands, especially after visiting the toilet and during food preparation.)

The dwarf tapeworm is the most common tapeworm in the world, particularly found in areas of poor sanitation and warm climates (such as Egypt, India and Latin America). One study reported that 4% of schoolchildren in the rural southeastern United States had the dwarf tapeworm. (Yes, children have been known to practice poor hygiene!).

Taeniasis is the medical term for the intestinal infection caused by adult-stage beef tapeworm (Taenia saginata) or pork tapeworm (Taenia solium). To prevent Taeniasis, always cook beef and pork to 160 °F to kill any larvae that may be present.

Most humans who carry a tapeworm have no symptoms, other than seeing parts or all of the tapeworm passed in their stool. Despite the common joke to the contrary, weight loss is not a symptom of tapeworm infection. On the other hand, children with large numbers of the dwarf tapeworm may complain of stomach pain or diarrhea. Fortunately, tapeworms can be cured with anti-parasite medication.

For more information on this topic, see the HealthLink article What You Can Do to Prevent Communicable Diseases.

Julie L. Mitchell, MD, MS, is an Assistant Professor of Medicine at the Medical College of Wisconsin. She practices internal medicine at the Froedtert & Medical College General Internal Medicine Clinic - East. Her column appears in the Milwaukee Journal-Sentinel.