Q Fever and Coxiella burnetii: Immune Response and Pathogenesis

Coxiella burnetii is the intracellular bacterium responsible for Q fever and is classified as a category B potential biological weapon. Primary infection by C. burnetii is often asymptomatic or mild and is accompanied by spontaneous recovery. In patients with valve lesions or immunosuppressed patients, including pregnant women, the infection may become chronic. C. burnetii survives and replicates within myeloid cells by subverting receptor-mediated phagocytosis and preventing phagosome maturation. Here, we summarize the existing knowledge regarding the host response to C. burnetii; we also discuss the mechanisms used by C. burnetii to survive within macrophages as well as the defective immune response that characterizes chronic Q fever.