This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology Pa-2 (RNA Virus Pa-1,2 & Miscellaneous Viruses), Subject name: Microbiology
[{'content': 'Rabies vaccine is prepared from: \nSelect and explain. \nA. Liver virus, B. Street virus, C. Fixed virus, D. None of the above.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 1. The Fixed virus is defined as a virus which is isolated after several serial intracerebral passages in rabbits and can be used for vaccine production. 2. Differences between street and fixed rabies viruses: Street virus Fixed virus Freshly isolated After serial intracerebral passages in rabbits Produce negri body Does not produce negri body Affect salivary gland Does not affect salivary gland Can cause fatal encephalitis Neurotropic but much less infective Incubation period - 1-2 weak Incubation period - 5-6 days Cannot be used for vaccine production Used for vaccine production', 'role': 'assistant'}]