to Case 116
This was a case of microsporidiosis. The diagnostic morphologic
features observed were:
- the presence of round to oval
spores of microsporidia (black arrows, Figure A). They will stain pinkish red
when using the Chromotrope 2R staining technique. Often, an equatorial
belt-like stripe can be seen in the spores.
within the size range of microsporidia. Spores of Encephalitozoon spp. measure 1.0 to 1.5 by 2.5 to 3.0
micrometers, consistently appearing larger than Enterocytozoon bieneusi
spores (0.8 to 1.4 micrometers). E. bieneusi is the most commonly
recognized species causing diarrhea in immunocompromised patients.
difference in size between the spores allows a tentative genus-level
diagnosis, but definitive confirmation depends on laboratory testing
using one or more of the techniques listed above. Green arrows in
Figure A indicate yeast cells present in the specimen,
and not a causal agent of disease.
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microsporidiosis, please click