This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Epidemic typhus cause and vector is \nSelect and explain. \nA. R. prowazki and louse, B. R. typhi and mite, C. R. conori and tick, D. R. akari and mite', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Epidemic Typhus Is a type of rickettsial disease of typhus group : Recrudence form of Epidemic typhus : Brill Zinsser Disease Was the \'most formidable rickettsial disease in past\' Causative agent: R.prowazekii Vector : Louse (p.capitis,p.corporis) Mode of Transmission: (Not by Louse bite) Scratching and inoculation with infected louse faeces Crushing infected louse on body Inhalation of infected louse faeces or dust Clinical picture : Prolonged febrile illness, Vasculitis Drug of choice : Tetracycline Under International Health Regulations (IHRs), "Louse borne typhus is a disease under surveillance" Ref: Park 25th edition Pgno : 316', 'role': 'assistant'}]