This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
True about cryptosporidium parum - 
Select and explain. 
A. Affect only in immunocompromised patient, B. It is one of the common oppounistic infection in AIDS, C. Cyst size 12-15 mm, D. AFB (+)ve cyst
B: It is one of the common oppounistic infection in AIDS
Answer: B: It is one of the common oppounistic infection in AIDS 
Explanation: Cryptosporidium has assumed great impoance as a frequent cause of intractable diarrhoea in AIDS patients. It can lead to acute self-limited diarrhoea in previously healthy persons and chronic life-threatening diarrhoea in immunocompromised subjects.Infection is acquired by ingesting the oocyst in contaminated food or drink.Infection in previously healthy persons may be asymptomatic or cause a sef-limited febrile illness with watery diarrhoea. It can also cause childhood and traveller's diarrhoea, as well as water-borne outbreaks. But in the HIV infected and other immunodeficient persons, infection leads to severe protracted diarrhoea, fever and emaciation. In AIDS, the parasite may invade the bronchial and biliary tracts and can be demonstrated in sputum.Diagnosis is made by demonstration of the oocyst in feces. With Jenner-Giemsa stain, the oocysts in faeces smears appear as blue spherical bodies containing a few eosinophilic granules. By cold Ziehl-Neelsen technique, the internal structures appear acid fast