Q fever is an infectious disease that is spread by domestic and wild animals and ticks.
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.
Blood tests to check for antibodies to Coxiella burnetti
Liver function test
Complete blood count (CBC)
Tissue staining of infected tissues to identify the bacteria
Electrocardiogram or echocardiogram to look at the heart
Treatment with antibiotics can shorten the length of the illness. Antibiotics that are commonly used include tetracycline and doxycycline. Pregnant women or children who still have any baby teeth should not take tetracycline by mouth because it can permanently discolor growing teeth.
Most people get better with treatment. However, complications can be very serious and sometimes even life threatening. Q fever should always be treated if it caused the symptoms.
Rarely, Q fever causes a heart infection that can lead to severe symptoms or even death if untreated. Other complications can include:
Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.