[Dientamoeba fragilis--an old parasite sparks new interest]

Dientamoeba fragilis is a protozoan parasite of the human colon with only the trophozoite stage identified. The exact mode of transmission is still unknown. Formerly considered to be apathogenic, several studies have suggested that D. fragilis has pathogenic properties. Common symptoms of the infection include diarrhea and abdominal pain. After reviewing the literature we suggest that treatment can be considered for patients with prolonged symptoms, provided no other causative agent has been found.