Coxiella burnetii infections (Q fever)

Q fever is a zoonosis caused by Coxiella burnetii, an intracellular Gram-negative spore-forming bacterium, the common animal reservoirs of which are cattle, sheep, and goats. Rats and mice have been implicated as reservoirs in some areas. In French Guiana the three-toed sloth is the reservoir. C. burnetti is trophic for the endometrium and mammary glands of female animals, and during pregnancy the organism reaches very high concentrations in the placenta such that at the time of parturition organisms are aerosolized and contamination of the environment occurs. Inhalation of even one microorganism can result in infection. Diagnosis is confirmed by serological testing: in acute disease antibodies to phase II antigen are higher than those to phase I, whereas the reverse is true in chronic disease.