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': 'A 9-month-old child is brought to the Health Depament to receive the second dose of oral polio vaccine, 2 weeks after the first vaccination. The child has mild diarrhea, so the decision is made to defer fuher immunizations. Bacteriologic examination of a stool culture is unremarkable; however, a small, single-stranded, positive RNA virus is isolated from the specimen. The viral isolate was not inactivated by ether. Which of the following viruses was most likely isolated? \nSelect and explain. \nA. Adenovirus, B. Hepatitis C, C. Parvovirus B19, D. Poliovirus', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Poliovirus, which is a single-stranded +RNA virus, is naked (i.e., non-enveloped) and hence will not be inactivated by lipid solvents such as ether. The live virus vaccine had colonized the intestinal tract of the infant and was still being shed 2 weeks after the earlier oral dose. This same virus, the vaccine strain, is likely to be found in sewage, as all vaccinated infants will shed virus for a period of time after immunization with OPV. Adenoviruses and parvovirus B19 also may cause diarrheal disease and both are non-enveloped; however, they both have a DNA genome. Hepatitis C is an enveloped, single-stranded +RNA virus; its major target organ is the liver, not the intestinal tract. It is a fragile agent that does not survive well outside the body and would not be isolated from raw sewage effluent.', 'role': 'assistant'}]