page_title: Q fever
section_title: Diagnosis
hierarchical_section_title: Q fever / Diagnosis
caption_attribution_description: Q fever management diagram, from Morbidity and Mortality Weekly Report (MMWR),
context_page_description: Q fever or query fever is a disease caused by infection with Coxiella burnetii, a bacterium that affects humans and other animals. This organism is uncommon, but may be found in cattle, sheep, goats, and other domestic mammals, including cats and dogs. The infection results from inhalation of a spore-like small-cell variant, and from contact with the milk, urine, feces, vaginal mucus, or semen of infected animals. Rarely, the disease is tick-borne. The incubation period is 9–40 days. Humans are vulnerable to Q fever, and infection can result from even a few organisms. The bacterium is an obligate intracellular pathogenic parasite.
context_section_description: Diagnosis is usually based on serology (looking for an antibody response) rather than looking for the organism itself. Serology allows the detection of chronic infection by the appearance of high levels of the antibody against the virulent form of the bacterium. Molecular detection of bacterial DNA is increasingly used. Culture is technically difficult and not routinely available in most microbiology laboratories.
  Q fever can cause endocarditis (infection of the heart valves) which may require transoesophageal echocardiography to diagnose.  Q fever hepatitis manifests as an elevation of alanine transaminase and aspartate transaminase, but a definitive diagnosis is only possible on liver biopsy, which shows the characteristic fibrin ring granulomas.
caption: Q fever management algorithm from the Centers for Disease Control and Prevention