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?: (A) Scrub typhus, (B) Rickettsial pox, (C) Brill-Zinsser disease, (D) Q fever
Answer is D. - 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