Species differentiation within Taenia is traditionally achieved by examining which parasite structures?

• A. Eggs in stool
• B. Proglottids and the scolex
• C. Larval forms
• D. Adult worm length

Answer: (B)

Differentiating Taenia species relies on features of the adult worm that are actually distinct between species. The scolex and the gravid proglottids provide the clearest, observable differences. The scolex can be armed with a rostellum bearing hooks in some species, while others have an unarmed scolex. The gravid proglottids show a characteristic pattern of uterine branches: some species have relatively few branches, while others have many. These structural details are stable and directly observable in the worm specimens, making them the most reliable way to tell Taenia species apart. In contrast, eggs recovered from stool look the same across Taenia species and are not useful for speciation, and larval forms or overall worm length are less dependable for accurate differentiation.