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Roundworms are a type of parasitic worm. Infections caused by roundworms are relatively common. Ascariasis is the most common roundworm infecti...

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What Is Ascariasis?

Ascariasis is an infection of the small intestine caused by Ascaris lumbricoides (A. lumbricoides), which is a species of roundworm.

Roundworms are a type of parasitic worm. Infections caused by roundworms are relatively common. Ascariasis is the most common roundworm infection. About 10 percent of the developing world is infected with intestinal worms, according to the World Health Organization (WHO). However, infections with parasitic worms are not as common in the United States, according to the Centers for Disease Control and Prevention (CDC).

Ascariasis is most common in places without modern sanitation. It’s transmitted through unsafe food and water. The infection usually causes no symptoms, but heavier infestations can lead to problems in the lungs or intestines.

What Causes an Ascariasis Infection?

You can become infected with ascariasis after accidentally ingesting the eggs of the A. lumbricoides roundworm. The eggs can be found in soil contaminated by human feces or uncooked food contaminated by soil that contains roundworm eggs. Children often become infected when they put their hands in their mouths after playing in contaminated soil, according to WHO. Ascariasis can also be passed directly from person-to-person.

After ingestion, the A. lumbricoides roundworm reproduces inside your intestine. The worm goes through several stages:

  • Swallowed eggs first hatch in the intestine.
  • The larvae then move through your bloodstream to your lungs.
  • After maturing, the roundworms leave your lungs and travel to your throat.
  • You’ll either cough up or swallow the roundworms in your throat. The worms that are swallowed will travel back to your intestine.
  • Once they’re back in your intestine, the worms will mate and lay more eggs.
  • The cycle continues. Some eggs are excreted through your feces. Other eggs hatch and return to the lungs.

Who Is at Risk for Ascariasis?

The roundworm is found worldwide, but it’s more frequently found in tropical and subtropical regions, including Latin America and sub-Saharan Africa. It’s also more common in areas where sanitation is poor.

 Environmental risk factors for ascariasis include:

  • lack of modern hygiene and sanitation infrastructure
  • use of human feces for fertilizer
  • living in or visiting a warm climate
  • exposure to an outdoor environment where dirt might be ingested

Exposure to roundworms can be limited by avoiding unsafe food and water. Keeping your immediate environment clean also helps. This includes laundering clothing exposed to unsanitary conditions and cleaning cooking surfaces well.

You should make sure to take precautions if you’re visiting a remote area. It’s important to:

  • boil or filter your water
  • inspect food preparation facilities
  • avoid unclean common areas for bathing

Children who are 3 to 8 years old are most likely to be infected.

What Are the Symptoms of Ascariasis?

You might not notice symptoms in the early stages of infection. You may notice more symptoms as the roundworm infestation grows.

Roundworms in your lungs can cause:

  • coughing or gagging
  • vomiting roundworms
  • wheezing or shortness of breath

Roundworms in your intestines can cause:

  • nausea
  • vomiting
  • irregular stools
  • visible worms in the stool
  • stomach or abdominal pain
  • weight loss

Some people with a large infestation may have other symptoms, such as fatigue and fever. A major infestation can cause extreme discomfort. You may have all or many of the above symptoms if you don’t receive prompt treatment.

What Are the Complications of Ascariasis?

Most cases of ascariasis are mild and don’t cause major problems. However, heavy infestations can lead to complications. Dangerous complications occur when worms gather in other areas of your body. They can include the following:

  • Intestinal blockage occurs when a mass of worms blocks your intestines causing severe pain and vomiting. Intestinal blockage is considered a medical emergency and requires prompt treatment.
  • Duct blockages occur when the worms block the passageways to your liver or pancreas.
  • Infections that lead to loss of appetite and poor absorption can cause slowed growth and poor nutrition. This puts children at risk of not getting enough nutrients, which can affect their growth.

Children are more likely to experience gastrointestinal complications because their intestines are small and at a greater risk of intestinal blockage.

How Is Ascariasis Diagnosed?

People in the early stages of this condition may not have any symptoms. Your doctor may use blood and stool samples to diagnose you. Abdominal X-rays can also be used to diagnose ascariasis.

If your doctor diagnoses ascariasis, they may recommend additional tests. Advanced imaging can show:

  • how many worms have grown to maturity
  • where major groups of worms are located
  • whether worms are in the areas around your internal organs

Tests might include:

  • CT scans
  • ultrasounds
  • MRI scans
  • endoscopy, which involves placing a small camera inside your body

It’s important for your doctor to determine how long you’ve had this condition. That way they can evaluate your risk of complications.

How Is Ascariasis Treated?

Roundworm is usually treated with antiparasitic drugs. Medications most commonly used for treatment include:

  • albendazole (Albenza)
  • ivermectin (Stromectol)
  • mebendazole

In advanced cases, other treatment may be needed. Surgery may be used to control a larger infestation.

What Is the Long-Term Outlook for an Ascariasis Infection?

Many people recover from ascariasis with minimal treatment. Symptoms may go away even before all of the worms are gone.

However, ascariasis can cause complications when there are large infestations. You should see your doctor if you think you’ve been infected with roundworms.

The best way to avoid ascariasis is through good hygiene and by dining at reputable places. Always wash your hands with soap and water before eating or handling food, and after using the bathroom. Teach your children to do the same. When traveling, drink bottled water and avoid raw fruits and vegetables unless you’re able to wash and peel them yourself. 

Written by: The Healthline Editorial Team
Edited by:
Medically Reviewed by:
Published: Nov 16, 2015
Published By: Healthline Networks, Inc.
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