Hymenolepis nana: the dwarf tape worm.

This article focuses on a clinical case of Hymenolepis nana infection in a 27-year-old woman presenting with abdominal pain, bloating, and alternating constipation and diarrhea over 12 months. Diagnosis was confirmed by stool microscopy showing H. nana eggs and colonoscopy revealing mobile flatworms in the terminal ileum, with biopsy indicating mucosal inflammation and presence of a cestode larva. H. nana, a dwarf tapeworm transmissible directly between humans, commonly affects institutionalized, immunocompromised, or malnourished individuals and can mimic irritable bowel syndrome symptoms. Treatment with oral praziquantel led to symptom remission and clearance of infection on follow-up stool examination.