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: Social & Preventive Medicine
[{'content': 'Not true about varicella infection - \nSelect and explain. \nA. Secondary attack rate is 90%, B. Lesions occur on flexor surfaces, C. Only single stage of lesion is present at a time, D. Reactivation occur in 10-30% cases', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The characteristic feature of chicken pox is "Pleomorphism", that is, all stages of the rash (papules, vesicles, and crusts) may be seen simultaneously at one time in the same area.\n\nChickenpox (varicella infection) is highly communicable by droplet infection with a secondary attack rate of approximately 90%.\nRashes of chicken pox are symmetrical and occur mostly on flexor surface.\nLatent infection is established in the cranial nerve, sensory ganglia, and spinal dorsal root ganglia. The virus may reactivate in immuno-suppressive conditions, resulting in herpes zoster in about 10-30% of persons.', 'role': 'assistant'}]