Ascariasis

Infestation with the roundworm, which lives in the small intestine of its human host. Ascariasis is common worldwide, especially in the tropics. The disease is spread by ingestion of worm eggs, usually from food grown in soil that has been contaminated by human faeces. Light infestation may cause no symptoms, but mild nausea, abdominal pain, and irregular bowel movements may occur. A worm may be passed via the rectum or vomited. A large number of worms may compete with the host for food, leading to malnutrition and anaemia, which in children can retard growth. Treatment is with anthelmintic drugs, such as levamisole, which usually produce complete recovery.