History and prospects of Coxiella burnetii research.

Coxiella burnetii, the causative agent of Q fever, is the only known intracellular pathogenic bacterium that replicates within the acidic, degradative confines of a eukaryotic phagolysosome. It appears that the bacterium nullifies or thwarts the toxic elements of this vacuole and evades both innate and adaptive immune responses. C. burnetii is ubiquitous in its geographic distribution with the disease prevalence more widespread than previously considered. Recent molecular and cell biological advances, along with improved instrumentation, have provided unique insight into the host-parasite interrelationship and revealed previously unknown virulence strategies of C. burnetii. An example is completion of the genome sequences of several strains of C. burnetii that has improved our understanding of pathogenic mechanisms used by the organism to cause disease in mammalian hosts.