Case #251 – May, 2009

A 45-year-old pig farmer from rural Georgia presented to his health care provider with abdominal pain, cramps and diarrhea. Stool specimens were collected in polyvinyl alcohol (PVA) and 10% formalin for ova and parasite (O&P) examination. The objects in Figures A and B, which measured on average 90 micrometers in length, were observed in low numbers in formalin-concentrated wet mounts of the stool. The objects in Figures C and D, which measured on average 12 micrometers in diameter, were seen in moderate numbers on trichrome-stained slides prepared from the PVA-preserved stool. What is your diagnosis? Based on what criteria?

Figure A

Figure B

Figure C

Figure D

This was a case of balantidiasis, caused by Balantidium coli (Figures A and B); also observed were cysts of Entamoeba polecki (Figures C and D). Diagnostic features included:

ciliated trophozoites of B. coli (Figures A and B) containing a cytosome and macronucleus, and within the size range (40-200 micrometers) of the species.
uninucleate cysts of E. polecki (Figures D and E) containing a nucleus with a pleomorphic karyosome and evenly-distributed peripheral chromatin, and many irregularly-shaped chromatoid bodies, as well as being within the size range (11-15 micrometers) of the species.

More on: Balantidiasis: Entamoeba polecki

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.