Tapeworms are flat segmented worms that live in the intestines of some animals. Animals can become infected with these parasites when grazing in pastures or drinking contaminated water.
Eating undercooked meat from infected animals is the main cause of tapeworm infection in people. Although tapeworms in humans usually cause few symptoms and are easily treated, they can sometimes cause serious, life-threatening problems. That's why it's important to recognize the symptoms and know how to protect yourself and your family.
Six types of tapeworms are known to infect people. They are usually identified by the animals they come from -- for example Taenia saginata from beef, Taenia solium from pork, and Diphyllobothrium latum from fish.
Tapeworms have a three-stage lifecycle: egg; an immature stage called a larva; and an adult stage at which the worm can produce more eggs. Because larvae can get into the muscles of their hosts, infection can occur when you eat raw or undercooked meat from an infected animal.
It is also possible to contract pork tapeworms from foods prepared by an infected person. Because tapeworm eggs are passed with bowel movements, a person who doesn't wash hands well after wiping and then prepares food can contaminate the food.
Sometimes tapeworms cause signs and symptoms such as:
However, often having tapeworms does not cause symptoms. The only sign of tapeworm infection may be segments of the worms, possibly moving, in a bowel movement.
In rare cases, tapeworms can lead to serious complications, including blocking the intestine. If pork tapeworm eggs are accidentally swallowed, they can migrate to other parts of the body and cause damage to the liver, eyes, heart, and brain. These infections can be life-threatening.
Treatment for Tapeworms
If you suspect you have tapeworms, you should see your doctor. Because there are different types of worms and tapeworms that can infect people, diagnosing a tapeworm infection may require a stool sample to identify the type of worm.
If worms are not detected in the stool, your doctor may order a blood test to check for antibodies produced to fight tapeworm infection. For serious cases, your doctor may use imaging tests such as computed tomography (CT) or magnetic resonance imaging (MRI) to check for damage outside the digestive tract.