Dientamoeba fragilis, a protozoan parasite in adult members of a semicommunal group.

Dientamoeba fragilis is an intestinal protozoan parasite associated with gastrointestinal symptoms. This study was undertaken in a semicommunal group reported to have a high prevalence of this parasite. Stools were collected from 81 adult group members. Intestinal parasites were observed in stool specimens of 45 (56%) of the 81 adults; D. fragilis was found in 33 (41%) subjects. This paper describes the clinical findings and treatment of 26 adults with D. fragilis alone or with a commensal. Gastrointestinal symptoms were observed in 22 (85%) of infected subjects; abdominal pain and excessive flatus were significantly more common in this group. diiohydroxyquin 650 mg three times a day for 20 days eliminated the parasite in 10 (83%) of the 12 treated, although three subjects required a second course of therapy. Parasitic infection should be considered in patients with vague gastrointestinal symptoms, especially those living in endemic areas, in close proximity, or with a history of foreign travel.