Coxiella burnettii (Q-Fever)

Q-Fever is a disease that results from infection with small, polymorph and gram-negative bacteria called Coxiella burnetii. After an outbreak in Brisbane, Australia, the responsible organism was isolated and named Coxiella burnetii in honour of Dr. Herald Rae Cox and Sir Frank Burnet. New molecular research demonstrated a close relationship to Legionella. The zoonosis Q-Fever is found everywhere except New Zealand (no data available). There is an extensive reservoir (mainly ticks) of C. burnetii. Ticks are an important vector of the pathogen in the transmission between domestic and wildlife animals. But the ticks are unimportant in the direct infection of humans. Cattles, sheep and goats are usually the source of transmission of this microorganism to humans. However cats, dogs and rabbits are also important in this regard. In most instances humans become infected with Coxiella burnetii following inhalation of contaminated aerosols (respiratory tract). The incubation period for Q-Fever in humans is about 2 weeks. The resulting illness can be divided into acute and chronic varieties. During the acute phase of illness antibodies to the phase II-antigen are formed. Anti phase-I antibodies in high titers are typical for a chronic disease. In areas where Q-Fever is endemic, 12% or more of the population have antibodies to C. burnetii. Most of the infections are subclinical or undiagnosed. The acute infection shows symptoms of high fever, shivers, muscle pain and headache. Later on more severe diseases such as pneumonia or hepatitis can occur. Infections during pregnancy can lead to an abort or premature birth. Approximately 1% of all infections become chronic. The most frequent organ manifestation in Q-Fever is endocarditis.