Roundworms are parasites that need to live in the body. These parasitic infections can cause diarrhea and fever. Types of roundworms in humans include pinworms and ascariasis. Often, roundworm infections come from traveling to countries with poor sanitation and hygiene. But kids can get them in the U.S. too. Medication can treat roundworms.


What are roundworms?

Roundworms are small organisms that can live in your intestine, which is part of your digestive system. Roundworms can live in the human intestine for a long time. They can be harmful and cause many problems, including abdominal (belly) pain, fever and diarrhea.

Roundworms have long, round bodies and can be of different sizes, depending on the type. The eggs or larvae (newly hatched roundworms) often live in infected soil or stool (poop).


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What is a parasite?

Roundworms are parasites — organisms that need to live on or in another creature to survive. Often, the parasite causes problems for its host (creature it depends on). For roundworms, they need the body of humans or other animals to mature into egg-laying adults.

How common are roundworms?

Hundreds of millions of people around the world are infected with roundworms at any given time. But many of these parasites are uncommon in the United States. Americans may come into contact with them when traveling to certain countries.

Pinworms are the most common roundworm infection in the United States. It affects 20 million to 42 million people, many of them children.


How does a person get infected with roundworms?

The route into the body depends on the type of roundworm. Many of these parasites enter the body through the mouth. Infection often happens from touching poop or soil that's infected with eggs and not washing hands (fecal-oral route). Pinworm infections result from touching eggs laid near the opening of the buttocks (anus).

You can accidentally ingest roundworm eggs by preparing food or touching soil that's contaminated. The eggs then hatch inside your body.

For other roundworms, eggs may hide in the food people eat. And in some cases, larvae can enter the body directly through your skin.

Regardless of how they enter, most roundworms end up in your intestines, causing infection or disease.

Who is at risk for roundworms?

Anyone can get roundworms. Roundworm infections are more common in children and people who are:

  • Living in poverty, especially in underdeveloped areas of the world.
  • Living in warm climates.
  • Living in an institution, such as a prison or mental health facility.
  • Not practicing good hygiene.


Are roundworms contagious?

Yes. If you come into contact with infected poop of people or animals, you can get roundworms. You can also get them by touching infected surfaces, like soil.

Can I get roundworms from my pets?

Yes. If your pet has roundworms, you can be exposed to the eggs or larvae in their poop. A pet with roundworms can spread the disease to many people. Talk to your veterinarian about protecting you and your pet from roundworms.

Symptoms and Causes

What causes roundworms?

Each type of roundworm has different causes, as well as different symptoms.

What are the causes and symptoms of roundworm infection of your intestines (ascariasis)?

This type of roundworm spreads through poor hygiene. It often lives in human feces (poop). People catch it through hand-to-mouth contact.

If you have a roundworm infection of your intestines (ascariasis), you may not have symptoms. You may see live worms in your poop though. If you do have symptoms, they may include:

What are the causes and symptoms of hookworm?

People get hookworm by walking barefoot on dirt mixed with infected poop.

People may not notice symptoms if their health is otherwise good. If someone does have symptoms, the signs may include:

  • Anemia, when you don’t have enough red blood cells, making you feel tired and weak.
  • Colic, a lot of crying and fussiness in an otherwise healthy baby.
  • Diarrhea.
  • Mild abdominal pain and intestinal cramps.
  • Nausea.

What are the causes and symptoms of pinworm?

Pinworm is the most common roundworm infection in the United States. It most often occurs in children and can spread easily in school or daycare. The infection starts when eggs enter the mouth and travel to the intestines. The eggs hatch and develop into adult pinworms.

A female pinworm then lays her eggs in and around the anus (opening of the buttocks). Without realizing it, people touch the eggs with their fingers. For example, a small child might touch or scratch their bottom or not wash hands after using the bathroom. Parents may not wash their hands properly after changing a diaper of a child with pinworms.

After touching an infected area, people may put their fingers in or near their mouths or touch surfaces. Pinworm eggs can attach to bedding, clothing, toys, doorknobs, furniture and faucets for up to two weeks.

Those with pinworm infections may experience mild symptoms or none at all. The most common symptom is itching around the anus or vagina. The itching can become intense after a pinworm lays eggs.

What are the causes and symptoms of strongyloidiasis?

This type of roundworm mainly lives in tropical and subtropical areas, where it’s warm year-round. But it can also live in other regions during warmer seasons. People get infected by touching contaminated soil. Strongyloidiasis enters through the skin and travels to the intestines.

Some people may experience mild symptoms or none at all. If you have a moderate infection, you may feel:

Severe strongyloidiasis infections may cause:

  • Anemia.
  • Chronic (long-lasting) diarrhea.
  • Weight loss.

What are the causes and symptoms of trichinellosis?

Trichinellosis is different than other roundworm infections. It’s not an intestinal infection. It affects your muscles. People get it through eating undercooked meat, especially sausage, pork, horse, walrus and bear meat.

Some people may experience mild symptoms or none at all. But you may feel tired or get stomach symptoms, including:

  • Diarrhea.
  • Stomach cramps.

When trichinosis enters the muscles, you may get:

  • Eye infection and rashes.
  • High fever.
  • Muscle pain and aches.
  • Swelling in the eyes and face.

What are the causes and symptoms of whipworm?

You get whipworm by:

  • Touching it with your hands.
  • Eating food that has whipworms on it.
  • Eating food that was grown in soil with whipworms.

There are usually no symptoms with whipworm. However, if you have a severe infection, you may experience:

  • Blood in your poop.
  • Diarrhea.
  • Stomach pains that come and go.
  • Weight loss.
  • Anemia.

Diagnosis and Tests

Should I call my healthcare provider if I may have roundworms?

Yes. It’s important to get a proper diagnosis for roundworms. Tell your provider if you've:

  • Come into contact with wild animals or infected pets.
  • Eaten raw or undercooked meats.
  • Seen a worm or part of a worm in your poop.
  • Traveled to an area with poor hygiene and sanitation in the last two years.

How are roundworms diagnosed?

Your healthcare provider will ask you about your medical history and symptoms. Then you'll probably need a blood test. Your provider may also ask for a stool sample to test it for eggs. To get a stool sample, your provider gives you a sterile (germ-free) container. You place a poop sample in the container and bring it to your provider or a lab.

Management and Treatment

How are roundworms treated?

While there are various kinds of roundworms, they usually all have the same treatment. Your provider will prescribe a medicine called albendazole. This medicine prevents the larvae from getting bigger or multiplying. The worms in your body then pass through your poop. You may not even notice it happening.

Depending on the type of roundworm, you may need to repeat the treatment after a few weeks. Doing so makes sure the parasites are completely gone.

You may also need a prescription for an iron supplement to help with anemia. And a prescription cream can help stop any itching.


Can I prevent roundworms?

Take steps to prevent roundworm infections:

Pet safety

  • Clean up dog or animal poop in your yard.
  • Get your pet dewormed. Talk to your vet about a deworming schedule that’s right for your pet.

Good hygiene

  • Make sure children don’t play near an animal’s poop.
  • Teach children not to eat dirt or soil.
  • Wash hands well with soap and hot water, especially after playing with pets or doing outdoor activities.

Food and drink safety

  • Don’t eat raw fruits and vegetables in areas with poor sanitation.
  • Don’t eat raw or undercooked meats, including meat from wild animals and pork, poultry, beef or fish.
  • If you’re traveling to an area without modern sanitation, only drink bottled water.
  • Wash garden-grown fruits and vegetables well.

Outlook / Prognosis

How long does roundworm treatment take to work?

The medicine destroys roundworms in about three days.

What’s the outlook for people with roundworm infection?

Most roundworm infections don’t cause long-term problems. Follow your provider’s instructions for taking your medicine. Take precautions to prevent an infection from happening again.

Living With

How should I take care of myself?

Take your medicine as prescribed. Wash bedding and towels in hot water. If you’re planning to travel to a high-risk area, talk to your provider about preventive medications.

When should I call my healthcare provider?

Contact your provider if you:

  • Have a red, itchy rash on your skin.
  • Have stomach problems that last longer than two weeks — such as diarrhea or a stomachache.
  • Have unexplained weight loss.
  • See a worm or piece of a worm in your poop.

What else should I ask my healthcare provider?

If you have a roundworm infection, ask your provider:

  • Will I need medication?
  • How long should I take medication?
  • Will the infection come back?
  • Will there be long-term health problems from the roundworm infection?
  • What can I do to protect myself from roundworms?

A Note from Cleveland Clinic

Roundworms are a group of parasites that includes pinworms and ascariasis. These tiny organisms enter your body, where they often live in your digestive system and cause problems. You can get roundworms by coming into contact with roundworm eggs or larvae. See your healthcare provider if you have symptoms of pinworm or other roundworms. A round of medication usually treats the infection. People don’t usually have long-term health effects from roundworms.

Medically Reviewed

Last reviewed on 05/18/2021.

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