Acid fast organism with oocyte of size 5 lam on stool examination, causing diarrhoea in HIV positive patient:

Ans (a) Cryptosporidium Parasite causing diarrhea on AIDS patient Parasite Site Mode of infection Oocyst Cryptosporidia Enterocyte in small intestine Ingestion of oocyst Blue spherical (= 5 mm) bodies in acid fast stain Microsporidia Intestine, Muscle, CNS Spore ingestion Spores are 2-4 pm in size with polar filaments or tubules Isospora belli Epithelial cells of small intestine Ingestion of mature oocyst Oval or flask shaped, 25 pm x 15 pm with two sporocyst and four sporozoites. Also acid fast Remo- Coccidian parasites are Isospora, Toxoplasma and Cryptosporidia Blastocytis hominis is round cell of 6-40 pm containing large membrane bound central body with nuclei in cytoplasm peripherally.