<prompt> A 35-year-old HIV positive patient comes with intractable diarrhea, crampy, abdominal pain and vomiting. Biopsy of small intestine was taken which shows cyst 10 um as given below. What is the appropriate diagnosis?CMVIsospora belliCryptosporidium parvumGiardia lamblia  <response>: - 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 andor 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 mgd of nitazoxanide NTZ 