Yukako Hirayama, Hiroko Sato, Keita Kamiyama, Suguru Hiramoto, Akihito Kimura, Ayumi Ito, Kuniko Yoshida, Norio Horiguchi, Keiko Kawai-Kowase
We describe a case of a man in his late 20s who presented with symptoms of diarrhea, abdominal pain, and passage of string-like materials following the consumption of raw whitebait. Stool analysis was negative for eggs and parasites. However, a worm segment corroborated by subsequent genetic sequencing confirmed infection with Diplogonoporus balaenopterae. Treatment with praziquantel led to complete resolution of symptoms without recurrence. This case demonstrates that marine tapeworm infections can occur even in non-coastal regions. This is likely due to the widespread availability of fresh seafood. This emphasizes the importance of obtaining a dietary history when diagnosing parasitic infections.