Which statement about parasites and chronic diarrhea is true?

• A. Tapeworms rarely cause diarrhea.
• B. Roundworms, hookworms, and whipworms are common causes of diarrhea.
• C. Protozoa never cause diarrhea.
• D. Only tapeworms cause chronic diarrhea.

Answer: (B)

Chronic diarrhea from parasites is most commonly linked to intestinal nematodes. Roundworms, hookworms, and whipworms frequently cause persistent diarrhea because they irritate the intestinal lining and disrupt absorption, especially when worm burden is high or exposure continues. Protozoa, such as Giardia and Entamoeba, can also cause chronic diarrhea, so it isn’t accurate to say protozoa never cause it. Tapeworms tend to produce few GI symptoms, so they are not a typical or exclusive cause of chronic diarrhea. Therefore, the statement that roundworms, hookworms, and whipworms are common causes best reflects the common parasitic contributors to chronic diarrhea.