<prompt> 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. What is the drug of choice in this patient?TMP-SMXNitazoxanidePrimaquineNiclosamide  <response>: In the given stool examination there is acid fast oocyst of size 8 to 10 microns most probably of Cyclospora which is a coccidian parasites so the drug of choice of Cyclospora is cotrimazole which is combination of trimethoprim and sulfamethoxazole. CRYPTOSPORIDUM PARVUM Spherical or oval 4-5 micrometer in diameter 4 sporozoites Acid fast Infective when passed in feces Under ultraviolet illumination, unstained oocyst are autoflourescent CYCLOSPORA CYTANENSIS Spherical or oval 8-10 micrometer 2 sporocysts 4-6micrometer , each sporocyst has 2 sporozoites Acid fast Not infective when passed in feces Under ultraviolet illumination, unstained oocysts are autoflourescent. ISOSPORA BELLI Ellipsoid 20-30 x 10-19 micrometer 2 sporocysts 9-14 x 7-12 micrometer , each sporocyst has 4 sporozoites Acid fast Not infective when passed in feces Under ultraviolet illumination, unstained oocyst are autoflourescent. 