Adult worms live in the lumen of the small intestine. A female may produce up to 240,000 eggs per day, which are passed with the feces .
Fertile eggs embryonate and become infective after 18 days to several weeks , depending on the environmental conditions (optimum: moist, warm, shaded soil).
After infective eggs are swallowed , the larvae hatch , invade the intestinal mucosa, and are carried via the portal, then systemic circulation to the lungs .
The larvae mature further in the lungs (10 to 14 days), penetrate the alveolar walls, ascend the bronchial tree to the throat, and are swallowed .
Upon reaching the small intestine, they develop into adult worms .
Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female.
Adult worms can live 1 to 2 years
The fertilized egg measures 45 to 75 mm Ч 35 to 50 mm. Mature female worms are estimated to produce an average of 200, 000 eggs daily. Fertilized eggs become infective within approximately 2 weeks in a moist, warm soil, where they can then survive for months to years.