The small size of these spherical structures (4-6 micrometers in diameter) and bright red staining using the Modified Safranin stain (which is similar to a modified acid fast stain) is characteristic for this species. Arthur Morris mentions that the differential would be the similar-appearing oocysts of Cyclospora, but that these can be excluded because they would be larger and also typically have a 'broken glass' internal appearance.
One reader commented that this could be C. parvum or C. hominis, the 2 most common species found in humans. However, there are a number of other species that may be less commonly found in humans, and it is not possible to tell the different species apart by morphology alone.
Thanks again to Florida Fan for this case!
Also, Blaine wanted to let us know that he hasn't forgotten about us, and created the following poem during his 'free time' between the numerous workshops that the CDC DPDx group is putting on:
No poems from Blaine, where did he go?
He’s just been too darn busy don’t you know.
As soon as we’re caught up
And our workshops are done
You’ll be treated to some parasitological poetry fun.