Dientamoeba fragilis. An unusual intestinal pathogen.

This is a case report of a gastrointestinal infection caused by Dientamoeba fragilis. It is a flagellate protozoan that is an uncommon etiology of gastrointestinal disease. Primarily characterized by diarrhea and abdominal pain, other symptoms such as flatulence, nausea, vomiting, fatigue, malaise, and weight loss occur. Diagnosis is made using multiple fresh stool samples that are preserved and permanently stained looking for the typical binucleate trophozoite. Since there is a distinct association with Enterobius vermicularis (possibly the mode of protozoan transmission), the human pinworm is also sought. Treatment of choice consists of diiodohydroxyquin in adults and metronidazole in children.