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Ascariasis

Medically reviewed by Drugs.com. Last updated on May 17, 2022.

Overview

Ascariasis (as-kuh-RIE-uh-sis) is a type of roundworm infection. These worms are parasites that use your body as a host to mature from larvae or eggs to adult worms. Adult worms, which reproduce, can be more than a foot (30 centimeters) long.

One of the most common worm infections in people worldwide, ascariasis is uncommon in the United States. Most infected people have mild cases with no symptoms. But heavy infestation can lead to serious symptoms and complications.

Ascariasis occurs most often in children in tropical and subtropical regions of the world — especially in areas with poor sanitation and hygiene.

Ascariasis worm

Ascariasis worms are typically pink or white with tapered ends. Female worms can be more than 15 inches (40 centimeters) long and a little less than a quarter inch (6 millimeters) in diameter. Male worms are generally smaller.

Symptoms

Most people infected with ascariasis have no signs or symptoms. Moderate to heavy infestations cause various signs or symptoms, depending on which part of your body is affected.

In the lungs

After you swallow the tiny (microscopic) ascariasis eggs, they hatch in the small intestine and the larvae migrate through the bloodstream or lymphatic system into the lungs. At this stage, you may experience signs and symptoms similar to asthma or pneumonia, including:

After spending 10 to 14 days in the lungs, the larvae travel to the throat, where you cough them up and then swallow them.

In the intestines

The larvae mature into adult worms in the small intestine, and the adult worms typically live in the intestines until they die. In mild or moderate ascariasis, the intestinal infestation can cause:

If you have a large number of worms in the intestine, you might have:

When to see a doctor

Talk to your doctor if you have persistent abdominal pain, diarrhea or nausea.

Causes

Ascariasis isn't spread directly from person to person. Instead, a person has to come into contact with soil mixed with human or pig feces that contain ascariasis eggs or infected water. In some developing countries, human feces are used for fertilizer, or poor sanitary facilities allow human waste to mix with soil in yards, ditches and fields. People can also get it from eating uncooked pig or chicken liver that is infected.

Small children often play in dirt, and infection can occur if they put their dirty fingers in their mouths. Unwashed fruits or vegetables grown in contaminated soil also can transmit the ascariasis eggs.

Life cycle of a worm

The whole process — from egg ingestion to egg deposits — takes about two or three months. Ascariasis worms can live inside your body for a year or two.

Risk factors

Risk factors for ascariasis include:

Complications

Mild cases of ascariasis usually don't cause complications. If you have a heavy infestation, potentially dangerous complications may include:

Prevention

The best defense against ascariasis is good hygiene and common sense. Follow these tips to avoid infection:

Diagnosis

To diagnose ascariasis, your doctor may review your symptoms and order tests.

In heavy infestations, it's possible to find worms after you cough or vomit. The worms can come out of other body openings, such as your mouth or nostrils. If this happens to you, take the worm to your doctor so that he or she can identify it and prescribe the proper treatment.

Stool tests

Mature female ascariasis worms in your intestine begin laying eggs. These eggs travel through your digestive system and eventually can be found in your stool.

To diagnose ascariasis, your doctor will examine your stool for the tiny (microscopic) eggs and larvae. But eggs won't appear in stool until at least 40 days after you're infected. And if you're infected with only male worms, you won't have eggs.

Blood tests

Your blood can be tested for the presence of an increased number of a certain type of white blood cell, called eosinophils. Ascariasis can elevate your eosinophils, but so can other types of health problems.

Imaging tests

Treatment

Typically, only infections that cause symptoms need to be treated. In some cases, ascariasis will resolve on its own.

Medications

Anti-parasite medications are the first line of treatment against ascariasis. The most common are:

These medications, taken for one to three days, kill the adult worms. Side effects include mild abdominal pain or diarrhea.

Pregnant women may take pyrantel pamoate.

Surgery

In cases of heavy infestation, surgery may be necessary to remove worms and repair damage they've caused. Intestinal blockage or holes, bile duct blockage, and appendicitis are complications that may require surgery.

Preparing for your appointment

Your family doctor might refer you to a doctor trained in digestive disorders (gastroenterologist). You may need to see a surgeon if the worms have blocked the intestines.

What you can do

Before your appointment, you may want to write down the answers to the following questions:

What to expect from your doctor

During the physical exam, your doctor may press on certain areas of the abdomen to check for pain or tenderness. He or she may also want a sample of stool for testing.

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