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?: (A) Cryptosporidium, (B) Cyclospora, (C) Enterocytozoon, (D) Giardia
Answer is B. 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.