Ascariasis

Causes and Risks:
This is the most common intestinal worm infection. It is found in association with poor personal hygiene, poor sanitation, or where human feces are used as fertilizer. Infection occurs when food or drink contaminated with roundworm eggs is ingested. The eggs hatch releasing larvae within the intestine. The larvae then migrate through the blood stream to the lungs, exit through the bronchial tree and are swallowed. (During migration through the lungs the larvae may produce an eosinophilic pneumonia .) Once back in the gut they mature into adult roundworms. Adult worms live in the intestine where they lay eggs that are expelled with the feces.

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

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 anthelmintic ("deworming") medications may be advised.

Symptoms:

Note: There may be no symptoms.

Signs and Tests:



Treatment:
The objective of treatment is to eliminate the worms with anthelmintic medications (medicatons that destroy intestinal parasitic worms).

Prognosis:
The probable outcome is usually good even without treatment. However, complications may be caused by migratory adult worms.

Complications:
In heavy infestation, the adult worms may migrate to the biliary (liver secretion) tract and cause an obstruction, a perforation (hole), or abscesses .

Call Your Healthcare Provider:
Call your health care provider if symptoms worsen or do not improve with treatment or new symptoms occur.


Roundworms are the most common type of worm infection. It is estimated that there are 4,000,000 cases in the United States at any time. Infection is more common in warm climates. Eggs are passed in the stool of infected animals and contaminate the soil. Ingestion of contaminated soil then leads to roundworm infection. (Courtesy of the Centers for Disease Control.)