Hookworms

Hookworms are a parasite passed through feces, and picked up through the feet. They can crawl up to 4 feet (1.2 m) through sandy soil, and die after around 7 days.

This is an excellent reason for:

• Proper sanitation, including adequate storage times and separation from areas used by humans. The principle of outhouses keeping human waste 6 feet (1.8 m) below the surface is based on the abilities on the hookworm.
• Wearing footwear in areas where fecal contamination might be present.