The parasite whose adult resembles a whip and whose eggs have bipolar plugs is which species?

The parasite whose adult resembles a whip and whose eggs have bipolar plugs is which species?

• A. Strongyloides stercoralis
• B. Toxocara canis
• C. Trichuris vulpis
• D. Toxascaris leonina

Answer: (C)

The key idea is recognizing both the adult worm’s shape and the distinctive egg morphology. A whipworm has a body that looks like a whip: a very slender, tapering front end and a thicker rear end. Its eggs are barrel-shaped with clear plugs at both poles, the polar plugs, which is a hallmark feature used to identify Trichuris eggs under the microscope. Putting those clues together points to Trichuris vulpis, the whipworm that commonly infects dogs. Other parasites listed don’t share this exact combo. Strongyloides stercoralis has slender threadlike adults and often produces larvae rather than the characteristic barrel-shaped eggs with polar plugs. Toxocara canis and Toxascaris leonina produce eggs that are more rounded or ovoid and lack the distinctive bipolar plugs, so they don’t match the description of whip-like adults with polar-end plugs.

The key idea is recognizing both the adult worm’s shape and the distinctive egg morphology. A whipworm has a body that looks like a whip: a very slender, tapering front end and a thicker rear end. Its eggs are barrel-shaped with clear plugs at both poles, the polar plugs, which is a hallmark feature used to identify Trichuris eggs under the microscope. Putting those clues together points to Trichuris vulpis, the whipworm that commonly infects dogs.

Other parasites listed don’t share this exact combo. Strongyloides stercoralis has slender threadlike adults and often produces larvae rather than the characteristic barrel-shaped eggs with polar plugs. Toxocara canis and Toxascaris leonina produce eggs that are more rounded or ovoid and lack the distinctive bipolar plugs, so they don’t match the description of whip-like adults with polar-end plugs.