This week's case was generously donated by Dr. Richard Bradbury from James Cook University in Australia. The following object was seen in the stool from a patient with advanced HIV infection living in Tanzania. Shown are preparations using differential interference contrast (DIC), darkfield, and fluorescent microscopy (wavelengths unknown). The objects measure approximately 25-30 micrometers in length. What is your identification?
8 comments:
Cystoisospora belli
Oh yes, Cytoisospora belli immature oocyst with only one sporoblast.It appears to me that all three photographs are from the same field. These oocysts autofluoresce under UV light excitation.
Florida Fan
An immature cyst of Cytoisospora belli. An oportunistic apicomplexan highly prevalent in HIV-AIDS patient
Agreed! Immature oocyst of Cystoisospora belli (formerly known as Isospora belli) containing only one sporoblast, which will evolve to two sporoblasts and later on will sporulate to become infective.
I have the impression that the first image is taken using DIC, the second one seems to be dark-field microscopy, and the last one could be autofluorescence at 450-490 nm. All coccidia (including Cystoisospora belli) will demonstrate fluorescence (without prior staining) when placed under UV-light. They will show up as bright blue structures when using an excitation filter of 330-365 nm, or green at 450-490 nm. Of note: Cryptosporidium is not placed among the coccidians anymore (moved to the Gregarines), and does not demonstrate autofluorescence either!
Cystoisospora belli/Patrik
Idzi: Thanks for the new information on Cryptosporidium. It is not very easy to keep the cranial contents up to date in retirement.
Etymologically do Gregarines come from being “gregarious”?
Florida Fan
Haha! Good point Florida Fan!
I suppose the name Gregarines could possibly originate from the word “gregarious”… if you have Cryptosporidium infection, you have a good chance of not being the only one (all your swimming buddies could have it as well)! 😅
Definitely Cystoisospora belli
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