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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 these 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.

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.

In rare cases, the disease affects children, especially those who live on a farm. In infected children younger than 3 years old, Q fever is usually noticed while looking for the cause of pneumonia.


Q fever is an infectious disease that is spread by domestic and wild animals and ticks.

Exams and Tests

A physical examination may reveal abnormal sounds (crackles) in the lungs or an enlarged liver and spleen. In the late stages of the disease, a heart murmur may be heard.

Tests that may be done include:

Outlook (Prognosis)

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.

Possible Complications

In rare cases, Q fever causes a heart infection that can lead to severe symptoms or even death if untreated. Other complications can include:


Pasteurization of milk destroys the bacteria that cause early Q fever. Domestic animals should be inspected for signs of Q fever if people exposed to them have developed symptoms of the disease.


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 have moderate symptoms similar to the flu. If symptoms occur, they may last for several weeks.

Common symptoms may include:

Other symptoms that may develop include:


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.

When to Contact a Medical Professional

Call your health care provider if you develop symptoms of Q fever. Also call if you have been treated for Q fever and symptoms return or new symptoms develop.

Review Date: 7/31/2016
Reviewed By: 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.

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