Q-fever is caused by: March 2005

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.