A patient with AIDS returned from Haiti with acute diarrhea. The stool revealed an oval organism (8 to 9 um in diameter) that was acid-fast and fluoresced blue under ultraviolet light. The most likely identification of this organism is

Coccidian-like bodies have been identified in stools of some patients with diarrhea. These organisms appear to be similar to blue-green algae and were referred to as Cyanobacterium-like until they were recently reclassified as Cyclospora. They are larger than the microsporidia and resemble neither Giardia nor Prototheca nor other algae-like organisms. Unlike Cryptosporidium, these organisms fluoresce under ultraviolet light Reference: Ananthanarayan and Paniker&;s Textbook of Microbiology Tenth edition