Life cycle of Ascaris: Adult worms (1) live in the lumen of the small intestine. A female may ...

Life cycle of Ascaris: Adult worms (1) live in the lumen of the small intestine. A female may produce approximately 200,000 eggs per day, which are passed with the feces (2). Fertile eggs become infective after 18 days to several weeks (3), depending on the environmental conditions (optimum: moist, warm, shaded soil). After infective eggs are swallowed (4), the larvae hatch (5), invade the intestinal mucosa, and are carried via circulation to the lungs (6). The larvae mature further in the lungs (10 to 14 days), ascend the bronchial tree to the throat, and are swallowed (7). Upon reaching the small intestine, they develop into adult worms.