What Is a Tapeworm Infection?

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Tapeworms are a type of parasitic flatworm, and some species can infect humans. The worms can live and grow in the digestive tract, a condition called taeniasis.

Infections are more common in the developing world, in areas where sanitation facilities are lacking and people may be in close contact with animals. Tapeworm infections in humans occur most often as a result of eating undercooked or raw beef, pork, or fish from an animal that was infected.

Another cause of infection is improper handwashing after coming into contact with tapeworms or tapeworm eggs. With pork tapeworms, the eggs can be ingested. When they hatch, they may go on to cause a serious infection called cysticercosis.

The different species of tapeworms include the beef tapeworm (Taenia saginata), pork tapeworm (Taenia solium), and the Asian tapeworm (Taenia asiatica). The latter is found in Asia and also infects pork. Freshwater fish can be infected with a broad tapeworm called Diphyllobothrium latum.

What is a Tapeworm Infection?
Verywell / Emily Roberts

Tapeworm Infection Symptoms

In most cases, infection with a tapeworm causes few or no symptoms in the digestive tract. If there are signs and symptoms, they can include:

  • Abdominal pain
  • Diarrhea
  • Fatigue
  • Hunger
  • Lack of appetite
  • Nausea
  • Passing tapeworm segments in the stool
  • Weight loss

In the case of infection with pork tapeworm (T . solium) eggs, the tapeworm larvae can migrate out of the digestive system and form cysts in other body parts (called cysticercosis). In rare cases, this may result in masses or lumps under the skin or in body tissues or organs.

If cysts develop in the central nervous system or the brain, there can be neurological symptoms (a condition called neurocysticercosis). This can be quite serious. Some of the signs and symptoms of neurocysticercosis can include headaches and seizures.

Infection with the fish tapeworm (D​. latum) may lead to a lack of vitamin B12, which may cause anemia. This condition can occur when your body lacks enough healthy red blood cells to carry sufficient oxygen to the tissues in your body.

Signs and symptoms of anemia can include:

  • Depression
  • Dizziness
  • Fatigue
  • Headaches
  • Low energy
  • Rapid heartbeat
  • Ringing in the ears

Causes

A few factors put you at risk for developing a tapeworm infection:

Undercooked Meat, Pork, or Fish

The most common way that people are infected with a tapeworm is through eating undercooked or raw meat, pork, or fish. If the animal had tapeworms, the person eating the meat can also become infected.

The life cycle of a tapeworm begins with eggs. Tapeworm eggs can live outside of a host and in the environment (such as in water or on plants) for days or even months. Animals may become infected after eating plants or feed or drinking water that contains tapeworm eggs.

Once inside an animal host, the eggs hatch and mature into young tapeworms. The worms are mobile and can migrate out of the intestine and into muscle tissue.

If not frozen or cooked properly to kill the worms, the animal's meat contains living tapeworms. They, in turn, can be passed on to a human who eats the meat.

Pork Tapeworm Eggs

A less common way of becoming infected with tapeworms is through contact with eggs from the pork tapeworm (T solium). The eggs are shed in the stool from an animal or a human who is infected.

The eggs can remain viable in the environment. This includes water, which is why it's important to ensure that the water you drink is germ-free.

The eggs can also be spread if an infected person doesn’t wash their hands well after going to the bathroom and then handles food that is eaten by others.

Pork tapeworm eggs can also live on surfaces. So it's also possible to become infected through the use of objects such as dishes or silverware that have eggs on them.

International Travel

While infection with tapeworms does occur in the United States, it is more common in the developing world.

Travel to areas where infections with tapeworms are more common is a risk factor.

Preventing infection while traveling includes making sure meat and fish are cooked well. In addition, fruits and vegetables should be cooked in boiling water or water that has been treated properly to kill any potential pathogens. It’s best to avoid any food or drink that is suspect.

Diagnosis

Diagnosis of infection in the digestive system includes testing the stool for tapeworms and/or looking at the anus area for eggs. Some people may notice tapeworms on or around their anus. A physician should see them during a physical exam.

In some cases, tapeworm segments may be visible in the stool. If this occurs, it is important to take a stool sample to a physician or a lab to get it tested.

A stool test can determine which type of tapeworm is present. It might be necessary to collect and test stool from several different bowel movements over a few days to make the diagnosis.

Blood tests for vitamin B12 levels and/or anemia may be done if there is an infection with the fish tapeworm. A blood test that looks for specific antibodies may be used to help diagnose cysticercosis. But this is uncommon.

Imaging tests such as CT scan or MRI may also be done if there are complications from an infection with pork tapeworm eggs that have migrated to other parts of the body.

Treatment

In cases of intestinal tapeworm infection, treatment requires a medication that will immobilize the worms. Once the worms are unable to hang onto the lining of the intestine, they will be passed out of the body during a bowel movement.

An antiparasitic drug commonly used to treat tapeworm infections is Biltricide (praziquantel). For infection with the dwarf tapeworm (Hymenolepis nana), a medication called Alinia (nitazoxanide) may be appropriate.

For complications from infection with pork tapeworm eggs that have formed cysts, treatment will depend on the location of the cysts. It may be necessary to use medication or another treatment to manage infection and associated complications in other areas of the body.

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This video has been medically reviewed by Casey Gallagher, MD.

Summary

Tapeworms are parasitic worms that can infect the digestive tract. Pork tapeworms can even move out of the gut and form cysts in other parts of the body, including the muscles and brain.

The most common way to get tapeworms is by eating beef, pork, or fish from an infected animal. It's also possible to get some types from contaminated water and surfaces.

Diagnosis may involve an exam, stool tests, blood tests, and imaging. The infection is usually treated with medications that cause the worms to be passed out of the body.

A Word From Verywell

Developing a tapeworm infection may sound scary. And it can be. However, the chances of developing this infection are rather slim, even when traveling to areas where it occurs more commonly. 

Infections with most types of tapeworms are manageable with medication. It's important to get the infection treated and follow up with a healthcare provider to ensure that the treatment was effective.

Frequently Asked Questions

  • Can you see a tapeworm in poop?

    You aren't likely to see an entire tapeworm in your stool. Once it's been treated, it detaches from the intestines and dissolves before it leaves your body. Sometimes eggs or segments of a tapeworm, called proglottids, that pass out in bowel movements are visible.

  • Is it possible to feel a tapeworm?

    Not while it's in your system. However, you may be able to feel one as it passes through your anus during a regular bowel movement.

  • Do tapeworms go away on their own?

    No. If a tapeworm infection isn't treated, the parasite is likely to stay put. This said, depending on the type of tapeworm, you may never know it's there.

  • How big can a tapeworm get?

    Pork, beef, and fish tapeworms can grow to between 15 feet and 30 feet long.The aptly named dwarf tapeworm can reach a maximum of 2 inches.

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9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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