This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Acid fast organism with oocyte of size 5 lam on stool examination, causing diarrhoea in HIV positive patient: \nSelect and explain. \nA. Cryptosporidium, B. Isospora belli, C. Microsoporidia, D. Blastocystis hominii', 'role': 'user'}, {'content': 'Answer: A \nExplanation: 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.', 'role': 'assistant'}]