Q fever is a zoonosis caused by Coxiella burnetii. Infection with Coxiella burnetii can be acute or chronic, and exhibits a wide spectrum of clinical manifestations. The most common are pneumonia, hepatitis, and fever. The main clinical manifestation of chronic Q fever is endocarditis. Primary infection in pregnant women, whether or not symptomatic, may be followed by abortion, prematurity, or low birth weight. Humans usually acquire infection after contact with infected animals or exposure to contaminated environments.