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Q fever
Definition
Q fever is a bacterial infection that can affect the lungs, liver, heart, and other parts of the body.
Alternative Names
Query fever
Causes
Q fever is found around the world and is caused by the bacteria Coxiella burnetii. The bacteria infects sheep, goats, cattle, dogs, cats, birds, rodents, and ticks, as well as some other animals. Infected animals shed this bacteria in:
- Birth products
- Feces
- Milk
- Urine
Humans usually get Q fever by breathing in contaminated droplets released by infected animals. Drinking raw milk has also caused infection in rare cases. People at highest risk for this infection are:
- Farmers
- Laboratory workers who work with Coxiella burnetii
- Sheep and dairy workers
- Veterinarians
People at highest risk include those with heart valve problems or weakened immune systems.
Symptoms
It usually takes about 20 days after exposure to the bacteria for symptoms to occur. Most cases are mild, yet some severe cases have been reported.
Common symptoms of acute Q fever may include:
- Dry cough
- Fever
- Headache
- Joint pain
- Muscle pains
Other symptoms may include:
- Abdominal pain
- Chest pain
- Rash
- Yellow skin (jaundice)
Symptoms of chronic Q fever may include:
- Chills
- Fatigue
- Night sweats
- Prolonged fever
- Shortness of breath
Exams and Tests
The health care provider will suspect Q fever in people who have been exposed to the Coxiella burnetii bacteria who develop:
- Endocarditis
- Flu-like symptoms
- Hepatitis
- Pneumonia
Q fever is diagnosed with a blood antibody test (serology).
Treatment
The main treatment for Q fever is with antibiotics. For early-stage (acute) Q fever, doxycycline is the recommended antibiotic.
If you have the infection for more than 6 months, it is called chronic Q fever. Your doctor may prescribe both doxycycline and hydroxychloroquine. You may need to take antibiotics for several months or years.
Outlook (Prognosis)
The outlook for people who get treated in the early stages of Q fever is generally good.
Chronic Q fever requires long-term treatment with antibiotics. Your health care provider should check you often to make sure the disease has not returned.
Possible Complications
- Bone infection (osteomyelitis)
- Encephalitis (brain infection)
- Infection of the heart valves (endocarditis)
- Inflammation of the heart lining (pericarditis)
- Inflammation of the heart muscle (myocarditis)
- Liver infection (hepatitis)
- Lung scarring (interstitial pulmonary fibrosis)
- Meningitis
- Pneumonia
When to Contact a Medical Professional
Notify your medical provider if you have symptoms of Q fever, especially if you believe you have been exposed to the bacteria. Although many different illnesses can cause similar symptoms, you may need to be evaluated for Q fever.
Prevention
People at risk (for example, farmers and veterinarians) should always:
- Carefully dispose of animal products that may be infected
- Disinfect any contaminated areas
- Thoroughly wash your hands
Pasteurizing milk can also help prevent Q fever.
Prompt treatment can prevent early Q fever from becoming chronic.
References
Marrie TJ, Raoult D. Coxiella burnetii (Q fever). In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 189.
Raoult D. Rickettsial infections. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap335.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. 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. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
