(Coxiella burnetii infection)
Q Fever is a worldwide zoonotic disease caused by the bacteria Coxiella burnetii. Although a variety of animals may be infected, cattle, sheep, and goats are the primary reservoirs for C. burnetii. Infected animals can shed the organism in birthing fluids, placenta, milk, urine, and feces. Coxiella is extremely hardy and resistant to heat, drying, and many common disinfectants, which enables it to survive for long periods in a contaminated environment (maternity pen, stall, barnyard). Infection of humans usually occurs by inhalation of C burnetii from air that contains barnyard dust contaminated by dried placental material, birth fluids, and excreta of infected animals. Other less common modes of transmission include ingestion of unpasteurized milk and dairy products, and tick bites.
The majority of infected humans exhibit mild flu-like symptoms or are asymptomatic. Acute and chronic clinical disease forms can occur in patients. Acute illness symptoms range from fever, headache, myalgia, non-productive cough, and gastrointestinal upset to more serious illness such as pneumonia, hepatitis, miscarriage, or myocarditis. Chronic Q Fever is a severe illness occurring in less than 5% of infected patients. Endocarditis is the most common manifestation of the chronic form. Diagnosis of Q Fever can be challenging, but the disease is often successfully treated when identified early.
Q Fever 101
How do people get sick with Q Fever?
People get infected with Q Fever by breathing in dust that has been contaminated by infected animal feces, urine, milk, and birth products that contain Coxiella burnetii. Touching an animal or being licked by an animal is not required to become sick with Q Fever. People may also get sick with Q Fever by eating contaminated, unpasteurized dairy products. Rarely, Q Fever has been spread through blood transfusion, from a pregnant woman to her fetus, or through sex.
Signs and Symptoms
About 5 out of 10 people infected with Coxiella burnetii will get sick. Illness typically develops two to three weeks after being exposed to the bacteria. Signs and symptoms of Q Fever may include:
- Chills or sweats
- Fatigue (tiredness)
- Muscle aches
- Nausea, vomiting, or diarrhea
- Chest pain
- Stomach pain
- Weight loss
- Non-productive cough
Symptoms can be mild or severe. People who develop severe disease may experience infection of the lungs (pneumonia) or liver (hepatitis).
Women who are infected during pregnancy may be at risk for miscarriage, stillbirth, pre-term delivery, or low infant birth weight.
Chronic Q Fever
A very small percentage of people (less than 5 out of 100) who become infected with C. burnetii bacteria develop a more serious infection called chronic Q Fever. Chronic Q Fever develops months or years following initial Q Fever infection. People with chronic Q Fever often develop an infection of one or more heart valves (called endocarditis). People with endocarditis may experience night sweats, fatigue, shortness of breath, weight loss, or swelling of their limbs. A healthcare provider will need to perform a series of tests to diagnose endocarditis.
Most people who are sick with Q Fever will recover without antibiotic treatment.
However, for people who develop Q Fever disease, treatment with two weeks of doxycycline antibiotic is recommended.
Chronic Q Fever
Chronic Q Fever is serious and can be deadly if not treated correctly. Chronic Q Fever infection requires months of antibiotic treatment, including doxycycline and hydroxychloroquine. Chronic Q Fever is more likely to occur in people with heart valve disease, blood vessel abnormalities, or in people with weakened immune systems. Women infected during pregnancy may also be at risk for developing chronic Q Fever.
- Q Fever vaccines are not available in the United States.
- Reduce your risk of getting Q Fever by avoiding contact with animals, especially while animals are giving birth. Animals can be infected with Coxiella burnetii and appear healthy.
- Do not consume raw milk or raw milk products.
- If you have been diagnosed with Q Fever and have a history of heart valve disease, blood vessel abnormalities, a weakened immune system, or are pregnant, talk to your healthcare provider about your risk for developing chronic Q Fever.
- Q Fever fact sheet P-01753 (Multiple languages)
- Center for Food Security and Public Health - Q Fever
This is a Wisconsin disease surveillance category II disease:
Report to the patient's local public health department electronically, through the Wisconsin Electronic Disease Surveillance System (WEDSS), by mail or fax using an Acute and Communicable Disease case report F-44151 (Word) or by other means within 72 hours upon recognition of a case.
Information on communicable disease reporting
Case Reporting and Investigation Protocol (EpiNet) P-01920 Q Fever (PDF)
CDC: Q Fever case report (PDF)
CDC: Q Fever diagnosis and laboratory guidance for clinicians