1. The unembryonated eggs are passed in feces.

2. In the soil, the eggs develop into a 2-cell stage.

3. The cells continue to divide (advanced cleavage stage).

4. Then the eggs embryonate and become infective in 15 to 30 days. They may be ingested when hands or food are contaminated with feces or feces-containing soil.

5. The eggs hatch in the small intestine and release larvae.

6. Larvae mature and establish themselves as adults in the cecum and ascending colon.