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?

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.