Q fever is caused by the bacteria Coxiella burnetii, which live in domestic animals such as cattle, sheep, goats, birds, and cats. Some wild animals and ticks also carry the bacteria.
You can get Q fever by drinking raw (unpasteurized) milk, or after breathing in dust or droplets in the air that are contaminated with infected animal feces, blood, or birth products.
Symptoms usually develop 2 to 3 weeks after coming in contact with the bacteria. This time is called the incubation period. Most people have no symptoms. Others may have moderately severe symptoms similar to the flu. If symptoms occur, they may last for several weeks.
People at risk for infection include slaughterhouse workers, veterinarians, researchers, food processors, and sheep and cattle workers. Men are infected more often than women. Most people who get Q fever are between 30 and 70 years old.
This disease is occasionally seen in children, especially those who live on a farm. In infected children younger than 3 years old, Q fever is usually discovered while looking for the cause of pneumonia.