Q fever is a worldwide disease caused by the bacteria
Coxiella burnetii.
Although a variety of animal species may be infected, cattle,
sheep, and goats are the primary reservoirs. Milk, urine, and
feces of infected animals secrete the bacterial organisms.
This particular organism is very hardy and resistant to heat,
drying, and many disinfectants. This resistance allows the
bacteria to survive for long periods in the environment.
Infection of humans usually occurs by inhalation of these
organisms from air that contains airborne barnyard dust
contaminated by dried placental material, birth fluids, and
excreta of infected animals.
Other modes of transmission to humans, including tick bites,
ingestion of unpasteurized milk or dairy products, and human to
human transmission, are rare. Humans are often very susceptible
to the disease, and very few organisms may be required to cause
infection.
