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
Embryonated Ascaris eggs are ingested by humans Larvae form in the small intestine and enter the liver via the enterohepatic circulation. From the liver they travel to the heart and lungs, out the alveolar spaces, up the trachea, and then are swallowed. Mature adult worms form in the small intestine, and they pass unembryonated eggs into the environment via the feces. Embryonation occurs in the soil within 2 to 4 weeks. Ingestion of the eggs completes the life cycle.
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.