Case #322 – April, 2012

A 28-year-old man presented to his health care provider with intermittent diarrhea, mild abdominal cramping, and low-grade fever. Travel history included camping in the northwestern United States. Stool specimens were collected in formalin and polyvinyl alcohol (PVA) and sent to a commercial lab for ova-and-parasite (O&P) examination. Figures A and B show what was observed in moderate frequency on a trichrome-stained smear made from the PVA-preserved stool. The objects of interest measured 12-15 micrometers on average in length. The images were captured at 1000x magnification. What is your diagnosis? Based on what criteria?

Figure A

Figure B

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

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