Q fever is a potentially severe bacterial disease caused by Coxiella burnetii. It most commonly affects goats, sheep, and cattle, although other animals can also carry the bacteria. Most animals have no symptoms, but infection may cause abortion in some cases. People can become infected through breathing in dust contaminated with infected animal products, such as feces, urine, milk, and birth products. Infection through direct contact or ingestion of infected animal products is also possible. The disease in people ranges from asymptomatic to severe or chronic illness. Women who are infected during pregnancy are at risk for pregnancy complications, including miscarriage.
The bacteria that cause Q fever are found worldwide, commonly in goats, sheep, and cattle, but also other animals. It can survive for a long time in dry, hot, or otherwise harsh environmental conditions. Because of this, it can be carried by wind over long distances from infected livestock.
In the United States, cases are most frequently reported from western and plains states where ranching and rearing of livestock are common. In Washington, 1 to 5 cases are typically reported each year. Most Washington cases do not have direct contact with animals, but instead likely become infected through inhalation of contaminated dust. The majority of cases exposed in Washington originate from Eastern WA, especially from areas where ranching is common, such as Grant and Yakima counties. However, cases of Q fever have been reported across the state.
People are most commonly infected by breathing in dust contaminated with infected animal products. The bacteria may be stirred up in dust and carried for long distances by wind, which can lead to infections miles from affected animals. People can also get Q fever through direct contact with placental material or other birthing products, urine, feces, or unpasteurized dairy products from infected animals, or by handling other contaminated materials, such as wool, straw, fertilizer, and laundry.
Very rarely, people also become infected through bites from infected ticks, receiving contaminated bone or marrow transplants, or handling C. burnetii cultures in the laboratory. In other rare cases, C. burnetii can be transmitted through sex or from a pregnant woman to her fetus.
People in certain professions are at increased risk for exposure to C. burnetii, including veterinarians, meat processing plant workers, dairy workers, livestock farmers, and researchers, and may need to practice additional precautions.
About half of people infected with Q fever actually experience symptoms associated with the infection. Acute symptoms of Q fever usually appear 2 to 3 weeks after exposure to the bacteria. Typical symptoms include sudden fever, chills, headache, fatigue, muscle aches, nausea, vomiting, diarrhea, and sometimes non-productive cough and severe sweats. Pneumonia and liver inflammation (hepatitis) can occur in severe cases. Rarely, Q fever can cause inflammation of the brain, heart, or gall bladder. Women infected during pregnancy may be at increased risk for miscarriage, stillbirth, pre-term delivery, or low infant birth weight.
Less than 5% of people who are infected with C. burnetii develop chronic disease during the months to years after their initial infection. Chronic Q fever often involves inflammation of the heart valves (endocarditis) but may also manifest as chronic inflammation in the liver, veins and arteries, joints, bones, or lungs. People with pre-existing heart valve disease, blood vessel abnormalities, or who are immunosuppressed, including pregnant women, are at greatest risk for developing chronic Q fever.
If you or your family member develop symptoms of Q fever after being exposed to livestock or consuming unpasteurized dairy products, visit your healthcare provider or contact your local health department.
There is no vaccine for Q fever in the United States. The main way to avoid Q fever is by avoiding contact with livestock, especially when they are giving birth. Consume only pasteurized milk or milk products. Animals infected with Q fever may not exhibit symptoms.
Where can I get more information?
For more information, contact your local health department.
Department of Health
- Q Fever for Healthcare Providers - Notifiable Conditions
- Guideline for Local Health Jurisdictions
- WA State Incidence Rate (PDF)
- Reporting Form (PDF)
Updated October 23, 2020