Whipworms

• A. Hookworms
• B. Whipworms
• C. Roundworms
• D. Tapeworms

Answer: (B)

This is about recognizing whipworms by their distinctive shape and where they live in the host. Whipworms are long, with a very thin, whip-like anterior end that embeds in the mucosa of the cecum and colon, and a thicker posterior portion that hangs into the lumen. Their eggs are lemon-shaped with two polar plugs, and these eggs are highly resistant in the environment, which helps explain why exposure to contaminated soil is a common route of infection.

This description stands out from other intestinal parasites. Hookworms, while also nematodes, are typically linked to the small intestine and have a different body morphology and egg appearance. Roundworms have larger, rounder eggs and reside in the small intestine as well. Tapeworms are flat, segmented worms that produce proglottids, not the lemon-shaped eggs characteristic of whipworms.