This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Haemophilus, Yersinia, Spirochaetes, Ricketssia, Chlamydia, Mycoplasma and Miscellaneous Bacteria), Subject name: Microbiology
[{'content': 'A patient presented with interstitial pneumonia,denied being bitten by insects.Of the following rickettsial diseases, which could have been caused without an insect bite? \nSelect and explain. \nA. Scrub typhus, B. Rickettsial pox, C. Brill-Zinsser disease, D. Q fever', 'role': 'user'}, {'content': "Answer: D \nExplanation: - Since the patient denied of being bitten by insects, the most likely rickettsial disease is Q fever. - Since out of 4 option only Q fever has no ahropod transmission . - It is transmitted by aerosol. - It is caused by Coxiella burnetti. - No rash occur in Q fever In scrub typhus vector is trombiculid mite In rickettsial pox the vector is mite. Caused by Rickettsia akari Brill Zinsser's disease / recrudescent typhus is reactivation of epidemic typhus in the human body", 'role': 'assistant'}]