Health Encyclopedia

Ascariasis

Definition

Ascariasis is an infection caused by a parasitic roundworm, Ascaris lumbricoides.

Causes, incidence, and risk factors

Ascariasis is the most common intestinal worm infection. It is found in association with poor personal hygiene, poor sanitation, and in places where human feces are used as fertilizer. Intake of food or drink contaminated with roundworm eggs causes infection.

The eggs hatch and release larvae within the intestine. The larvae then move through the bloodstream to the lungs, exit up through the large airways of the lungs, and are swallowed back into the stomach and intestines.

During movement through the lungs the larvae may produce an uncommon form of pneumonia called eosinophilic pneumonia. Once back in the intestines, they mature into adult roundworms. Adult worms live in the intestine where they lay eggs that are present in feces.

It is estimated that 1 billion people are infected worldwide. Ascariasis occurs in all ages, though children seem to be affected more severely than adults.

Symptoms

Most of the time, there are no symptoms. However, symptoms may include:

Passing worms in stool
Vomiting up worms
Worms exiting through the nose or mouth
Low-grade fever
Cough
Bloody sputum
Wheezing
Shortness of breath
Skin rash
Vomiting
Stomach pain

Signs and tests

The patient may show signs of malnutrition. Tests to diagnose this condition include:

Treatment

Treatment includes medications that paralyze or kill intestinal parasitic worms, such as albendazole or mebendazole. If there is a blockage of the intestine caused by a large number of worms, endoscopy or, rarely, surgery may be needed.

Expectations (prognosis)

Most people recover from the infection, even without treatment. However, complications may be caused by adult worms that move to certain organs or multiply and cause a blockage in the intestine.

Complications

Biliary (liver secretion) tract obstruction
Perforation (hole) in gut
Blockage in the intestine

Calling your health care provider

Call your health care provider if you have symptoms suggestive of this disease, particularly if you have traveled to areas which may be affected. Also call if symptoms worsen, do not improve with treatment or if new symptoms occur.

Prevention

Improved sanitation and hygiene in developing countries will reduce the risk in those areas. In areas where this disorder is common, routine or preventive (prophylactic) treatment with deworming medications may be advised.

Review Date:10/9/2006
Reviewed By:D. Scott Smith, M.D., MSc, DTM&H, Chief of Infectious Disease & Geographic Medicine, Kaiser Redwood City, CA & Adjunct Assistant Professor, Stanford University. Review provided by VeriMed Healthcare Network.

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