The pathogens occur all over the world and can result in a Q fever infection in humans. The transmission of coxiellas to humans occurs primarily through dust and droplets via the respiratory tract. It has already been known for some time that professional groups like shepherds, shearers, slaughter house personnel, farmers and veterinarians are exposed to a higher risk of falling ill with Q fever infection than other persons. It has been established that the permanent dealing with possible infection foci results in higher antibody determination in the persons concerned.
Sources of infection
Coxiella brunetii has a broad host range but is detected primarily in sheep, goats, cattle and wild ruminants. In natural herds the pathogen circulates between wild ruminants, birds and ticks. The latter serve as a reservoir but also as a vector. Ticks remain infected during their entire life and can pass on the pathogen to their progeny. A classical infection path for animals and also for humans is the inhalation of infected tick faeces. The propagation of C. burnetii is, however, not exclusively linked to ticks. Infected animals can excrete the pathogen with all secretions and excrements so that a tick-independent transmission can occur from animal to animal and/or to humans.
Coxiella (C.) burnetii is a pleomorphic (rod-like, coccoid lanceolate) gram-variable bacterium from the family of Rickettsiaceae. The germ with a length of 0.4 to 1.0 mm and a diameter of 0.2 to 0.4 mm can still be detected under a light microscope. It lives obligately on an intracellular basis and cannot multiply outside the host cell.
C. burnetii is characterised by a high resistance to chemical and physical influences. The duration of survival is particularly high in dried materials.