Dientamoeba fragilis infection has been associated with diarrhea and other
gastrointestinal complaints but not any life-threatening disease. It is
not uncommon in children, especially in day-care settings, and can be
treated with a variety of drugs. Its transmission remains a mystery as
the organism does not appear to have a resistant stage. Current thinking
is that it may be co-transmitted with pinworm infections as there is a
statistical correlation between the two. If not pinworms then direct
transmission via ingestion of fecally contaminated food or on
contaminated fingers is the most likely route.
Dientamoeba does not last long in stool (hence the name fragilis)
and so must be diagnosed in fresh material (not old or refrigerated)
and not all laboratories are good at diagnosing it. Not many people
actually work on it so surprisingly little is known about its basic
biology other than through microscopy.
Dientamoeba, although ameboid, is actually related to the trichomonad
Hope this helps!
C. Graham Clark, Ph.D.
Laboratory of Parasitic Diseases,
National Institutes of Health,
Bethesda, MD 20892-0425, USA
e-mail: gclark at nih.gov