1. Disease caused by infection with Ascaris or related ascarid nematodes or worms.
2. Infestation with or disease caused by a parasitic roundworm Ascaris lumbricoides.

The most common worm infection in people

Infection with the intestinal roundworm is considered the most common worm infection which occurs in humans.

• Ascaris eggs are found in the soil.
• Infection occurs when someone accidentally ingests (swallows) infective ascaris eggs.
• Once in the stomach, larvae (immature worms) hatch from the eggs.
• The larvae are carried through the lungs then to the throat where they are swallowed.
• Once swallowed, they reach the intestines and develop into adult worms.
• Adult female worms can grow over twelve inches (4.8 cm) in length.
• Adult male worms are smaller.
• Adult female worms lay eggs that are then passed in the feces; this cycle takes between two and three months.
• Adult worms can live one to two years.

Infection occurs worldwide

It is most common in tropical and subtropical areas where sanitation and hygiene are poor. Children are infected more often than adults. In the United States, infection is not common and occurs more often in the rural areas of the southeast.

Pigs can be infected with ascaris. Occasionally, a pig infection can be spread to humans; this occurs when infective eggs, found in the soil and manure, are ingested.

Infection is more likely if pig feces is used as fertilizer in the garden; crops then become contaminated with ascaris eggs.

When people are seriously infected, they may have abdominal pain. While the immature worms migrate through the lungs, those who are infected may cough and have difficulty breathing.

If anyone has a very heavy worm infection, the intestines may become blocked. Chronic ascaris infection can stunt the growth of children.

Diagnosis is most commonly made by finding the worm eggs in the stool. Larvae can be identified during the lung migration phase in sputum or gastric aspirate (stomach juice). Adult worms are occasionally passed in the stool or through the mouth or nose.

The way to prevent infection with ascaris

• Always avoid coming in contact with soil that may be contaminated with human feces.
• Do not defecate outdoors.
• Dispose of diapers properly.
• Wash your hands with soap and water before handling food.
• When traveling to countries where sanitation and hygiene are poor, avoid water or food that may be contaminated.
• Wash, peel, or cook all raw vegetables and fruits before eating.