Q Fever
A zoonotic infection caused by Coxiella burnetii, usually acquired by breathing contaminated particles from infected livestock or their birth products.
What causes Q Fever?
Q fever is caused by Coxiella burnetii bacteria. People are usually infected by inhaling contaminated dust from sheep, goats, cattle, or their birth products; raw milk is another potential exposure.
Symptoms and what to notice
Many infections are asymptomatic. Acute illness can cause high fever, severe headache, fatigue, chills, muscle aches, cough, nausea, vomiting, diarrhea, chest pain, hepatitis, or pneumonia.
How long can it last?
Symptoms typically begin 2 to 3 weeks after exposure. Acute illness may last several weeks. A small minority develop chronic Q fever months or years later, often involving heart valves or blood vessels.
How serious is Q Fever?
Chronic Q fever can cause life-threatening endocarditis or vascular infection. Risk is higher with heart-valve disease, vascular grafts or aneurysms, pregnancy, or weakened immunity.
Treatment and management
Doxycycline is first-line treatment for symptomatic acute Q fever, typically for 14 days, and works best when started early. Chronic Q fever usually requires prolonged doxycycline plus hydroxychloroquine under specialist care.
Vaccine: who and when?
No Q fever vaccine is licensed or commercially available in the United States. Q-Vax is used in Australia after screening but is not a U.S. option. Prevention relies on occupational controls, avoiding animal birth products, and not consuming raw milk.
Cost note: Patient cost varies by product, provider, insurance, location, and eligibility. Many recommended vaccines are covered in network without cost sharing, and qualifying children may use the Vaccines for Children program.
Trusted source
Patient cost varies by insurance, provider, location, and eligibility. Coverage and public-health access differ, so listed prices are examples rather than guaranteed patient prices. This page is for general education and does not replace individualized medical advice, diagnosis, vaccination assessment, or treatment.
Q Fever: Symptoms, Causes, Treatment, Prevention, and Vaccine Information
Q fever is an occupational and environmental zoonosis. Coxiella burnetii survives well in dust, and animal placentas and birth fluids can contain very high concentrations. Infection ranges from no symptoms to pneumonia or hepatitis. The uncommon chronic form is disproportionately dangerous and requires long follow-up and specialist treatment.
Important: This page is for general education. It does not replace diagnosis, treatment, vaccination advice, or emergency care from a qualified healthcare professional.
Quick Facts
| Topic | Current information |
|---|---|
| Cause | Q fever is caused by Coxiella burnetii bacteria. People are usually infected by inhaling contaminated dust from sheep, goats, cattle, or their birth products; raw milk is another potential exposure. |
| Main symptoms | Many infections are asymptomatic. Acute illness can cause high fever, severe headache, fatigue, chills, muscle aches, cough, nausea, vomiting, diarrhea, chest pain, hepatitis, or pneumonia. |
| Typical course | Symptoms typically begin 2 to 3 weeks after exposure. Acute illness may last several weeks. A small minority develop chronic Q fever months or years later, often involving heart valves or blood vessels. |
| Treatment | Doxycycline is first-line treatment for symptomatic acute Q fever, typically for 14 days, and works best when started early. Chronic Q fever usually requires prolonged doxycycline plus hydroxychloroquine under specialist care. |
| Vaccine status | No Q fever vaccine is licensed or commercially available in the United States. Q-Vax is used in Australia after screening but is not a U.S. option. Prevention relies on occupational controls, avoiding animal birth products, and not consuming raw milk. |
History and Public-Health Importance
The disease was first described among Australian abattoir workers in the 1930s; the letter Q reflected its initially unknown cause. It is now recognized worldwide. U.S. cases occur among ranchers, dairy and meat-processing workers, veterinarians, laboratory staff, and people living near infected animals. National surveillance and occupational precautions help identify outbreaks.
What Causes Q Fever?
Q fever is caused by Coxiella burnetii bacteria. People are usually infected by inhaling contaminated dust from sheep, goats, cattle, or their birth products; raw milk is another potential exposure.
People usually inhale contaminated aerosols generated during animal birthing, manure handling, transport, or environmental disturbance. Direct animal contact is not always remembered because bacteria can travel in dust. Person-to-person transmission is rare. Pasteurization prevents milkborne exposure.
Symptoms and Typical Course
Many infections are asymptomatic. Acute illness can cause high fever, severe headache, fatigue, chills, muscle aches, cough, nausea, vomiting, diarrhea, chest pain, hepatitis, or pneumonia.
About half of infected people may develop illness after two to three weeks. Fever, intense headache, fatigue, and muscle pain can accompany pneumonia or hepatitis. Fever often improves within about three days of effective doxycycline. Fatigue may persist. Chronic disease can appear long after apparently mild or asymptomatic infection.
Complications and Who Is at Higher Risk
Chronic Q fever can cause life-threatening endocarditis or vascular infection. Risk is higher with heart-valve disease, vascular grafts or aneurysms, pregnancy, or weakened immunity.
Chronic endocarditis or vascular infection can damage valves, grafts, aneurysms, and organs and can be fatal. Pregnancy infection may lead to obstetric complications. Hepatitis, pneumonia, neurologic disease, and prolonged post-Q-fever fatigue can occur. High-risk patients require serologic monitoring after acute illness.
How It Is Diagnosed
Diagnosis uses paired serology for phase I and phase II antibodies and sometimes PCR early in illness. Antibodies may be negative during the first week, so clinicians should not delay treatment when exposure and symptoms strongly suggest Q fever. Chronic disease assessment includes antibody patterns and imaging of heart valves or blood vessels.
Treatment and Recovery
Doxycycline is first-line treatment for symptomatic acute Q fever, typically for 14 days, and works best when started early. Chronic Q fever usually requires prolonged doxycycline plus hydroxychloroquine under specialist care.
Adults with acute symptomatic disease usually receive doxycycline 100 mg twice daily for 14 days. CDC provides separate guidance for pregnancy and young children. Chronic Q fever often requires doxycycline and hydroxychloroquine for 18 months or longer with drug-level, eye, heart, vascular, and serologic monitoring. Treatment decisions require specialist oversight.
Vaccine Information
No Q fever vaccine is licensed or commercially available in the United States. Q-Vax is used in Australia after screening but is not a U.S. option. Prevention relies on occupational controls, avoiding animal birth products, and not consuming raw milk.
No FDA-approved Q fever vaccine is available. Australia uses Q-Vax for selected occupationally exposed adults only after skin and blood testing because vaccinating someone with prior immunity can cause severe local reactions. U.S. workers must rely on engineering controls, personal protective equipment, training, animal-health practices, and surveillance.
Prevention
Avoid contact with placentas and birth fluids, use appropriate respiratory and barrier protection in high-risk work, handle manure and contaminated materials safely, ensure good ventilation, and consume only pasteurized milk products. Facilities should maintain occupational health plans for exposed workers.
When to Seek Medical Care
Contact a clinician for fever or severe headache after livestock, birthing, abattoir, or laboratory exposure. Seek urgent care for breathing trouble, chest pain, confusion, pregnancy with illness, or symptoms in someone with valve or vascular disease.
Frequently Asked Questions
Can Q fever spread from person to person?
It is rare. Most infections come from inhaling contaminated particles from infected animals or environments.
Why can tests be negative early?
Antibodies take time to develop. Treatment may begin from clinical suspicion before confirmatory serology becomes positive.
Is chronic Q fever common?
No, but it is serious and occurs more often in people with valve disease, vascular abnormalities, pregnancy, or immune compromise.
Is there a U.S. vaccine?
No. A vaccine used in Australia is not licensed or commercially available in the United States.
Key Takeaway
Q fever often follows inhalation near infected livestock. Early doxycycline treats acute disease, while high-risk patients need long follow-up for potentially fatal chronic infection.
Medical, treatment, and vaccine information was reviewed against official U.S. public-health guidance available through September 2026.