Humans may become infected with raccoon roundworms by

• A. Contact with raccoon feces
• B. Inhaling eggs
• C. Boiling water
• D. Swallowing something contaminated with roundworm eggs

Answer: (D)

Infection happens when a person swallows embryonated raccoon roundworm eggs from the environment. The eggs are shed in raccoon feces and become infectious after development in soil or on surfaces. Humans are incidental hosts, and ingestion of these eggs allows the larvae to migrate through the body, potentially reaching the nervous system. Therefore, swallowing something contaminated with roundworm eggs directly represents that fecal-oral route by which infection occurs. Simply touching feces doesn't transmit infection unless the eggs are ingested, inhaling the eggs isn’t the typical route for this parasite, and boiling water would kill the eggs rather than transmit them.