A patient with AIDS had an acute episodes of diarrhea. The stool examination revealed an oval structure (8 to 9u in diameter) that was acid-fast and fluorescent blue under ultraviolet light. The most likely identification of this organism is?

Acid fast structures that autofluoresce under UV light suggests the coccidian protozoa as the cause of the diarrhea. The size of 8-9 microns helps to arrive at the answer of Cyclospora. =Cyclospora, Cystoisospora and Cryptosporidium are coccidian protozoa that cause oppounistic intestinal infections in HIV patients.