Q Fever is caused by a bacterium (Coxiella burnetii). Individuals who have frequent direct contact with animals, including veterinarians, meat workers, and sheep and dairy farmers, are at higher risk. Q fever is rarely fatal. Most patients get Q fever by coming in contact with animals infected with the Q fever bacteria, their tissues, or fluids. Transmission may occur through breathing contaminated air or dust from an area with a large concentration of animals. Tissues from animals giving birth pose a particular risk. People can also become infected indirectly from animals through contaminated materials like wool, straw, and fertilizer. Transmission by tick bites can occur, but is rare in the United States. There is a risk of Q fever from consumption of contaminated raw milk. Sheep, cattle, goats, cats, dogs, some wild animals such as bobcats and rodents, birds, and ticks carry the bacteria. Most infected animals do not show signs of illness, but Q fever may sometimes cause abortion. The bacterium can be shed in large numbers when an infected animal gives birth.
Only about one-half of all people infected with C. burnetii show signs of illness. For patients who become ill, the first symptoms of Q fever resemble the flu and may include fever, chills, sweats, headache, and weakness. Q fever may rarely progress to affect the liver, nervous system, or heart valve. Q fever is diagnosed by identifying the bacteria in tissues or through a blood test that detects antibody to the organism.
Patients with mild transient illness usually do not require treatment. Patients with severe Q fever infection may be treated with two to three weeks of antibiotics. Patients with heart valve deformities should see their doctor for treatment to prevent infection of their heart valve. If treatment is delayed until late (i.e., heart) symptoms occur, patients may need to take antibiotics for months or years. If permanent damage to the heart valve occurs, surgery may be necessary.
Placenta, other birth products, and aborted fetuses should be disposed of immediately. Owners should seek veterinary assistance if their animals have reproductive or other health problems.