A 35 year old HIV positive patient comes with intractagble diarrhea, crampy, abdominal pain and vomiting. Biopsy of small intestine was taken which shows cyst < 10 mm as given below. What is the appropriate diagnosis?

Kinyoun stain positive and clinical features like diarrhea in a immunocompromised individual highly suggestive of organism -Cryptosporidium parvum. Its oocyst is of size 2-6 micron and it is pink coloured. Cryptosporidium, microsporidia, and Isospora belli are the most common oppounistic protozoa that infect the GI tract and cause diarrhoea in HIV-infected patients. Diarrhoea is accompanied by crampy abdominal pain, nausea and/or vomiting. Diagnosis- stool Cryptosporidium examination or biopsy of the small intestine. Diarrhoea is noninflammatory, and the characteristic finding is the presence of oocysts that stain with acid-fast dyes. Treatment: - 2000 mg/d of nitazoxanide (NTZ)