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Case #338 - December, 2012

A 42-year-old pig farmer presented to his local medical facility with intermittent diarrhea and abdominal cramping. A stool specimen was collected in 10% formalin for laboratory testing. Figures A and C were captured at 200x magnification and show what was found in high numbers. Figures B, D, and E show a higher magnification (400x) of the same objects. What is your diagnosis? Based on what criteria?


Figure A


Figure B


Figure C


Figure D


Figure E

Case Answer

This was a mixed infection with Ascaris lumbricoides and Balantidium coli. Morphologic features shown in the figures included:

  • unembryonated, fertile eggs of A. lumbricoides demonstrating a thick wall (Figures A-D) and with a mammillated layer (Figures C and D).
  • large smooth-walled cyst of Balantidium coli (Figures A and B).
  • trophozoite of B. coli demonstrating cilia, a large macronucleus, and a cytostome (Figures C and E).

More on: Ascariasis; Balantidiasis

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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