<prompt> Q-fever is caused by: March 2005Rochaemelia quintanaMycoplasma bovisCoxiella burnettiMycoplasma hominis  <response>: Ans. C: Coxiella burnetti Q fever results from infection by C. burnetii Coxiella burnetii which is a rickettsia. Q fever is a zoonosis zoonosis is a disease which is transmitted from animals to man. The major primary sources of human infection of Q fever are infected with Coxiella burnetii cattle, sheep, and goats. But, cats, rabbits, pigeons, and dogs can also transmit C. burnetii to humans. Coxiella burnetii uses several techniques to escape immune system as well as the harsh environment where it lives. It forms spores to survive in harsh environments and it escapes intracellular killing in macrophages by immune system by inhibiting ceain steps and adapts to the acidic environment of intracellular environment. 