Tapeworm Infection

Reviewed/Revised Jul 2023
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What are tapeworms?

Tapeworms are long, flat worms that look like a piece of tape or ribbon. There are many different kinds of tapeworms. Some kinds are over 15 feet (4.5 meters) long, and one is over 30 feet (9 meters).

  • Different kinds of tapeworms live in the flesh of different animals and fish

  • You get tapeworms by eating undercooked food from animals with tapeworms in their flesh

  • Then the tapeworms grow inside your intestines

  • Doctors check your stool for tapeworm eggs

  • Worm pills usually kill tapeworms

  • Cook your food thoroughly so you don't get tapeworms

What causes tapeworm infection?

Animals and fish sometimes eat things contaminated with tapeworm eggs. The eggs hatch and burrow into the muscles of the animal or fish and form cysts.

A Beef Tapeworm

Most of the time, you get tapeworm infection when you:

  • Eat undercooked meat or fish that has tapeworm cysts

The cysts hatch into worms in your intestines. Then the tapeworms attach themselves to the lining of your intestines and grow.

Less often, people eat things contaminated with tapeworm eggs. Then the tapeworms can form cysts in your muscles. They also can form cysts in your liver, brain, and other organs and make you very sick.

What kinds of animals can give me tapeworms?

The most common animals that carry tapeworms you can get are:

  • Cattle (beef tapeworm)

  • Pigs (pork tapeworm)

  • Fish that live in fresh water

But many other animals can carry tapeworms, including dogs, cats, sheep, and many wild animals.

What are the symptoms of tapeworm infection?

Even big tapeworms in your intestines may not cause any symptoms. You may have a little diarrhea or a mild belly ache.

Tapeworm cysts that form in your body can cause serious symptoms depending on where they are:

  • Brain: Headache, seizures, coma, death

  • Spinal cord: Weakness or paralysis

  • Liver: Belly pain, yellow skin and eyes (jaundice)

  • Lungs: Cough, chest pain

How do doctors tell I have tapeworm infection?

Doctors find tapeworms in your intestines by:

  • Looking for tapeworm eggs in your stool (poop) using a microscope

Doctors find tapeworm cysts in your organs by doing imaging tests such as CT (computed tomography) scan or MRI (magnetic resonance imaging).

How do doctors treat tapeworm infection?

A single dose of worm medicine usually kills tapeworms in your intestines.

If you have tapeworm cysts in your organs, you may need surgery to remove them.

How can I prevent tapeworm infection?

In many countries, government inspectors check meat and fish for tapeworm cysts. Even so, the most important things to do are:

  • Thoroughly cook meat and freshwater fish

  • Not eat raw freshwater fish

Freezing can kill fish tapeworms, but the fish has to be frozen for 7 days at -4° F (-20° C) or below. Smoking and drying meat and fish do not kill tapeworm cysts.

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