Coxiella burnetii (Q Fever)

Q fever is an almost worldwide zoonosis caused by the intracellular gram-negative coccobacillus Coxiella burnetii. Infection typically occurs after exposure to contaminated aerosols from animal reservoirs, which are most commonly cattle, sheep, goats, and soft ticks. The disease occurs sporadically and has been associated with large outbreaks caused by emerging clones. These outbreaks, including the largest ever recorded in the Netherlands, have led to a better understanding of the disease. Emerging data from the United States and other areas suggest that Q fever is underdiagnosed because it mimics many other common infections. Acute Q fever manifests as a flulike illness with pneumonia, hepatitis, and endocarditis, although acute disease can have a myriad of presentations. Patients may develop a persistent focalized infection including endocarditis or less commonly vascular infections or osteomyelitis. Chronic fatigue occurs in some patients following acute infection and can last for several years. Patients with acute infection require follow-up including echocardiography to ensure a chronic infection does not develop or that it is recognized quickly to prevent morbidity. Guidelines and recommendations for diagnosis, management, and treatment of acute and chronic Q fever have been published, although there is debate surrounding certain aspects. Despite more than 80 years of studying the disease, the name Q fever (“Q” for query) remains appropriate, as many questions still exist regarding the diagnosis and management of the disease.