Q fever is a disease caused by the bacteria known as Coxiella burnetii. Cattle, sheep, and goats are known as the primary reservoirs. These microbes are excreted in milk, birth fluids, urine, and feces of infected animals and can survive for long periods in the environment.
Infection of humans usually occurs by inhalation of these organisms from air. Other modes of transmission include tick bites, ingestion of unpasteurized milk or dairy products.
In less than 5% of cases, the affected people with acute Q fever infection develop a chronic Q fever.