Answer to Case 761

Answer to the Parasite Case of the Week 761: Diphyllobothrium/Dibothriocephalus/Adenocephalus (diphyllobothriid) species. These worms are commonly referred to as the broad fish tapeworm based on the fact that their proglottids are broader than they are tall and they are acquired through eating undercooked fish. The diphyllobothriid tapeworms have a very characteristic 'rosette-shaped' central uterus which we can see here:

This picture also nicely shows the craspedote nature of the proglottids, characteristic of the diphyllobothriid tapeworms. The term craspedote refers to the overlapping arrangement of the proglottids - like shingles or tiles. This feature, along with the uterine structure, is helpful in differentiated the diphyllobothriid tapeworms from Taenia species.

Thanks again to Dr. Taylor Williams and Karl Kirby for donating this highly educational case.