Case of the Week 447

This week's case is in honor of Memorial Day and was generously donated by Florida Fan. I've actually revived this from a previous case, since the colors (red, white and blue) are so beautiful with Florida Fan's rendition of the modified safranin stain. The red objects seen below were found in stool and measure approximately 10 micrometers in diameter.

Identification?

Answer to Case 447

Answer: Cyclospora cayetanensis oocysts

The beautiful red staining of these round oocysts is characteristic, whether using the standard modified acid fast stain or the modified safranin stain.

Answer to Case 597

Answer: Cyclospora cayetanensis oocysts, unsporulated

I figured this was a very timely posting, as we are currently experiencing an outbreak of cyclosporiasis in the Midwestern United States. It's a good reminder to keep an eye out for these round refractile structures in routine stool preparations and follow-up with confirmatory testing (e.g., modified acid fast, modified safranin, examination for autofluorescence, molecular amplification).

I also figured this was a timely case for my United States readers as the confirmatory modified acid fast and safranin stains provide beautiful red, white and blue images for the 4th of July celebrations (American Independence day; my apologies to my British friends)

Here is a gorgeous image from a modified safranin stain of C. cayetanensis oocysts from Florida Fan:
(from Case of the Week 447):