Dientamoeba fragilis infection

Dientamoeba fragilis infection is associated with mild diarrheal illness. D. fragilis was present in 4% of stool samples in a survey of 40,000 Canadians. It causes diarrhea in returned travelers. It is easy to miss by routine procedures in the parasitology laboratory because it lacks a cyst stage.

CASES/YEAR
16,000 (US); 300,000 (Global)
CATEGORY
Gastroenteritis--Noninflammatory
AGENT TYPE
Protozoa
OTHER NAMES
ACUITY
Subacute/Chronic
INCUBATION
INITIAL SYMPTOMS
Asymptomatic or diarrhea;
PRECAUTIONS
COMMENTS
The pathogenesis of Dientamoeba fragilis is not well understood, but it has been associated with a mild diarrheal illness. D. fragilis was present in 4% of stool samples in a survey of 40,000 people in Canada and has been documented as a cause of diarrhea in returned travelers. Because it has a trophozoite stage but not a cyst stage, it is easy to miss by routine procedures in the parasitology laboratory. "There is an unexplained association with eosinophilia." [Guerrant, p. 631]
DIAGNOSTIC
Detection of trophozoites in stool sample after fixing and permanent staining; [Guerrant, p. 631] Yield is increased by examining several samples on alternate days; [Harrison ID, p. 1123]
SCOPE
Global
SIGNS & SYMPTOMS
  • >fatigue, weakness
  • G abdominal pain
  • G diarrhea
  • G nausea, vomiting
  • H eosinophilia
  • *weight loss
ANTIMICROBIC

Yes

VACCINE

No

ENTRY
Ingestion
SOURCE
Person-to-Person, Human Fecal-Oral
RESERVOIR
Human
RISK FACTORS
  • Ingest infectious agents in food/water
DRUG LINK
CDC - Dientamoeba fragilis
REFERENCES FOR CASES/YEAR
1. (US) No data found; Assume same cases/yr as Cyclospora;
2. (Global) No data found; Assume same rate as Cyclospora;