1. Eggs are passed in the stool, and if they are deposited in a warm, moist place on loose soil, larvae hatch in 1 to 2 days.

2. The eggs release rhabditiform larvae, which grow in the feces or soil.

3. After 5 to 10 days, the larvae become infective.

4. When they come in contact with the human host, they penetrate the skin and are carried through the blood vessels to the heart and then to the lungs. They penetrate into pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed.

5. The larvae reach the small intestine, where they mature into adults. Adult worms live in the lumen of the small intestine. They attach to the intestinal wall, feed on blood (resulting in blood loss by the host), and produce eggs.