Medically Reviewed by Minesh Khatri, MD on August 11, 2022
5 min read
Ascariasis is a kind of roundworm infection you get in your intestines. You get it when you come into contact with the worm’s eggs in contaminated food, soil, or water. You can't get it from another person.
As many as 1.2 million people worldwide have it.
Ascariasis is more common in warm and humid climates, in areas where manure is used as fertilizer, or where poor sanitation allows human waste to mix with the soil. It isn’t common in the United States.
Children are most at risk because they put objects in their mouths and often play in the dirt. Most people who get the infection are under the age of 10.

In some cases, a mild infection won't cause any noticeable symptoms. Other times, if the infection is more serious (large infestation of worms) you can have a variety of symptoms.  You’re most likely to have signs of ascariasis in your lungs and intestines.

Roundworms in your lungs can cause:

  • A cough that won’t stop

  • Trouble breathing or shortness of breath

  • Wheezing

Roundworms in your intestines can cause:

  • Stomach pain (mild to severe)

  • Nausea

  • Diarrhea or blood in poop

  • Tiredness

  • Vomiting

  • Weight loss

  • Worms in poop or vomit

  • Blockages in your intestines

  • Duct blockages in your liver or pancreas

Heavy infestations can also keep children from growing at a normal rate because they don't get enough nutrients.

The life cycle of the worm begins when you swallow a bit of infected soil or eat unwashed fruits or vegetables grown in that soil. After that:

  • The eggs travel to your intestines, where they hatch.

  • Larvae then get into your lungs through your bloodstream or the network of vessels in your lymphatic system.

  • A week later, the larvae leave your lungs and travel through your airway and into your throat, where you cough them up and swallow them.

  • The parasites grow into adult worms after they go back into your intestines. Males can grow up to 9.8 inches and females up to 13.8 inches. Female worms can lay up to 200,000 eggs a day. The eggs leave your  body when you poop.

  • If the poop mixes with soil, eggs can live there for several years.

The cycle from egg to adult takes about 2-3 months. Adults can live up to 2 years in your intestines.

Risk factors of ascariasis include:

  • Age. Ascariasis mostly affects children age 10 and younger. This could be because kids in that age group tend to play in the dirt.

  • Warm climate. People who live in warmer climates are more likely to get ascariasis than those who live in cooler climates. It’s more common in developing countries that have warm weather year-round, but also affects those in the Southeastern United States.

  • Lack of sanitation. Ascariasis tends to be found in areas where human waste mixes with the soil or those where people have less access to soap and clean water.

  • Raising pigs or fertilizing plants with pig manure.

  • Eating raw liver from pigs or chickens.

If a doctor thinks you or your child has ascariasis, they may do:

  • Stool tests. The doctor will send a poop sample to a lab, where technicians look for eggs or worms through a microscope.

  • Imaging tests:

    • X-rayscan show large masses of worms in the belly or lungs.

    • CT scans are special X-rays. They take pictures from different angles deep inside your body to look for worms.

    • Ultrasounduses sound waves to make images. The doctor can use it to look for worms in your liver or pancreas.

    • Endoscopy is a procedure where a camera attached to a long tube is put into your stomach and intestine through your mouth. It can show if worms are blocking the intestines, pylorus (a tube that connects your stomach and small intestine), pancreas and other parts of their gut.

    • MRIs use magnets and sound waves to create images deep inside the body to see if worms are blocking any ducts.

Doctors use antiparasitic medications to treat ascariasis. These include:

Symptoms usually go away in a week. Doctors will check for eggs and worms again around 3 weeks later.

If there are any infestation-related blockages or infections, you may need surgery to take care of them.

Traditional treatments for ascariasis usually involve herbs and are more widely used outside the U.S.

Most people who get ascariasis don’t have any  complications. But a heavy infestation can cause problems like:

  • Stunted growth. Children with ascariasis may have slowed growth from not getting enough nutrients. They often lose their appetite. And sometimes their bodies take a long time to absorb digested food.

  • Intestinal blockage.A large number of worms in your intestines can cause blockage. This often results in severe stomach cramps and vomiting. You can even get holes in your intestines, which could lead to internal bleeding. Or you might get a hole in your appendix, which could result in appendicitis. Any of these things is a medical emergency.

  • Duct blockages. Sometimes worms can cause small tubes (ducts) in your liver or pancreas to get blocked. This can cause severe pain.

Because ascariasis spreads through soil that’s been mixed with human waste, it's best to stay away from those areas and from food grown in contaminated dirt. If you travel to another country or to an area where there might be poor sanitation, it’s always a good idea to:

  • Wash your hands often, especially when you prepare and eat food.

  • Thoroughly wash, peel, and cook all raw vegetables and fruits.

  • Drink bottled water.

  • Keep your fingernails trimmed.

  • Clean your clothing and bedding regularly.