Q fever.

Q fever is an acute febrile illness first described in 1935 and now seen in many parts of the world. Human infection follows exposure to animals, especially domestic livestock. Recent outbreaks in metropolitan areas have implicated cats as the carrier of disease to humans. The etiologic agent, Coxiella burnetti, belongs to the family Rickettsiaceae, although it has distinct genetic characteristics and modes of transmission. Most recent attention has been focused on a number of large outbreaks of Q fever associated with medical research involving pregnant sheep. Although most infections are self-limited, some patients require prolonged treatment. Recent vaccines have had encouraging success in the prevention of disease in individuals at high risk of exposure.