Q fever is a disease caused by the bacteria Coxiella burnetii. Cattle, sheep, and goats are most likely to get the disease, but they can also pass it to humans. The bacteria is found in the milk, urine, and feces of infected animals, and it can also be passed during birth. The organisms are very resistant to heat, drying, and disinfectants, which means the bacteria can live for long periods of time.
How is Q fever transmitted to humans?
Human get infected if they breathe in the organisms from barnyard dust, dried placental materials, birth fluids, or excreta from infected animals. Although rare, humans can also get it from consuming unpasteurized dairy products, through tick bites, or from other humans.
How common is Q fever?
It only takes a few organisms for humans to become infected, and humans are fairly susceptible to the disease. There were approximately 160 cases reported in the U.S. in 2007, but the rate decreased to 131 cases in 2010.
What is the difference between acute Q fever and chronic Q fever?
Acute Q fever usually develops within 2-3 weeks of infection, and people usually recover completely, although some people may suffer from complications due to the disease. Chronic Q fever is a severe form of Q fever occurring in less than 5% of acutely infected patients. It can present itself within 6 weeks of infection or years after infection occurs.
What are the symptoms of Q fever?
Symptoms of acute fever usually develop within 2-3 weeks of infection. Approximately 50% of patients will not experience symptoms, and not everybody will experience the same symptoms. Symptoms include:
- Very high fever (up to 104°-105° F)
- Severe headache
- Malaise (generally feeling unwell)
- Chills and/or sweats
- Dry cough
- Nausea and/or vomiting
- Abdominal pain
- Chest pain
What complications are associated with Q fever?
Although most people will recover completely, complications can occur. Less than 2% of people with acute fever will die. Complications associated with acute Q fever include:
- Granulomatous hepatitis (inflammation of the liver)
- Myocarditis (inflammation of the heart tissue)
- Central nervous system complications
- Pre-term delivery or miscarriage in pregnant women
Complications associated with chronic Q fever include:
- Endocarditis in about 60%-70% of reported cases with a fatality rate of approximately 25%-60%
- Aortic aneurysms
- Infections of the bones, liver, and reproductive organs
Coxiella burnetii can persist in humans long after infection occurs. A post-Q fever fatigue can occur in between 10%-25% of humans with acute Q fever. Symptoms of post-Q fever fatigue include:
- Constant or recurring fatigue
- Night sweats
- Severe headaches
- Eye sensitivity to light
- Muscle or joint pain
- Mood changes
- Difficulty sleeping
How is Q fever diagnosed?
Diagnoses can be difficult, because symptoms of Q fever will vary from person-to-person. Antibodies may not show in body fluid tests for 7-10 days after infection. Oftentimes, doctors may need to use their best judgement and patient history to determine if a patient has Q fever. Symptoms, and patient history regarding travel and work can help a doctor diagnose Q fever. Diagnoses can later be confirmed using specialized blood tests.
How is Q fever treated?
If Q fever is suspected, antibiotic treatment should begin immediately, preferably within 3 days of symptoms showing. If treatment begins within 3 days of symptoms, fever will usually subside within 72 hours. Patients with more severe Q fever may have a longer waiting period. Doxycycline is the most effective at preventing sever Q fever. Other antibiotics are available for pregnant women or those allergic to Doxycycline.
How is at risk for Q fever?
Acute Q fever:
- Those who work with animals, such as ranchers, veterinarians, or animal researchers
- Those who live on or near farms
- People that visit or live on farms in the spring
Chronic Q fever:
- Pregnant women
- Immunosuppressed persons
- People with heart valve defects
How can I prevent Q fever?