Diagnostic Findings [Last Modified: ]
Dientamoeba fragilis infection
[Dientamoeba fragilis]
Causal Agent Life Cycle Geographic Distribution Clinical Features Laboratory Diagnosis Treatment

Microscopy

Dientamoeba fragilis trophozoite line drawing Dientamoeba fragilis trophozoite, trichrome stain Dientamoeba fragilis trophozoite, trichrome stain
A B C

Dientamoeba fragilis trophozoite, trichrome stain Dientamoeba fragilis trophozoite, trichrome stain
D E

A, B, C, D, E: Dientamoeba fragilis trophozoites (A, line drawing; B-E, trichrome stain).  Dientamoeba fragilis is a flagellate that must be morphologically differentiated from the amebas, especially Endolimax nana and Entamoeba hartmanni.  Dientamoeba fragilis has no cyst stage, and its trophozoites usually measure 9 to 12 µm (range 5 to 15 µm).  While most trophozoites are typically binucleate, some have only one nucleus (E).

Dientamoeba fragilis trophozoite Dientamoeba fragilis trophozoite
F G

F: Dientamoeba fragilis binucleated trophozoites, trichrome stain.
G-I: D. fragilis binucleated trophozoites, iron-hematoxylin stain.

Dientamoeba fragilis trophozoite Dientamoeba fragilis trophozoite
H I

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