Q fever is an infectious disease caused by the bacterium Coxiella burnetii. It is primarily transmitted to humans from animals, particularly cattle, sheep, and goats. People can become infected by inhaling contaminated dust or aerosols from animal products, such as urine, feces, or birth fluids. Symptoms of Q fever can range from mild flu-like signs to severe pneumonia. Some individuals may also experience chronic complications, such as endocarditis, which affects the heart. Diagnosis is typically made through blood tests, and treatment usually involves antibiotics, especially in more severe cases.