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Case #327 - July, 2012

A three-year-old boy with no known international travel history was taken to his pediatrician with diarrhea and abdominal cramping. The patient was one of several children in his day care presenting with diarrhea. Stool specimens were collected in polyvinyl alcohol (PVA) and 10% formalin and sent to the State Health Lab for ova-and-parasite (O&P) examination. Figures A-D show what was observed in high numbers on a slide stained with trichrome made from the PVA-preserved stool. The objects of interest measured on average 10-13 micrometers long at their greatest length. What is your diagnosis? Based on what criteria?


Figure A


Figure B


Figure C


Figure D

Case Answer

This was a case of Dientamoeba fragilis infection. Figures A, C, and D showed binucleate forms of the trophozoite. Figure B showed a uninucleate form. The organisms in Figures A, B, and D also had ingested yeast.

More on: Dientamoeba fragilis

Images presented in the monthly case studies are from specimens submitted for diagnosis or archiving. On rare occasions, clinical histories given may be partly fictitious.

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  • Page last reviewed: August 24, 2016
  • Page last updated: August 24, 2016
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