Q fever is a bacterial zoonosis (disease capable of being transmitted from animals to people) caused by Coxiella burnetii, a rickettsial organism. Anyone can get the disease if they are infected with C. burnetii bacteria.
C. burnetii may be found in sheep, cattle, goats, cats, dogs, some wild animals (including many wild rodents), birds, and ticks. Animals shed the organism in their urine, feces, milk, and especially in their birth products.
Transmission
Most infected animals do not show signs of illness. Q fever is spread to people primarily through airborne dissemination of contaminated dust. Dust becomes contaminated from the tissues or bodily fluids of animals infected with C. burnetii bacteria.
Direct contact with infected animals or materials that they have contaminated (such as straw or other bedding materials) may also cause an infection. Raw or unpasteurized milk from infected cows or goats may be capable of spreading C. burnetii. Direct person-to-person spread is not likely.
Symptoms
Q fever in humans is usually either asymptomatic or mistaken for an acute viral illness due to the symptoms of fever, chills, headache, weakness, malaise (a general sick feeling), and severe sweats.
The incubation period is variable, although 2-3 weeks is considered common. In most cases, the illness is of short duration, lasting less than two weeks, even without treatment.
Rare complications include pneumonitis (inflammation of the lungs), neurologic problems, and among people with abnormal or prosthetic heart valves, endocarditis (inflammation of the heart). Complications are more likely to occur among people who have weakened immune systems.
Risk Factors
People at highest risk for Q fever are those who work with infected animals, including veterinarians, researchers, meat workers, sheep workers and farmers.
Testing and Treatment
Blood tests can be used to diagnose Q fever.
Q fever can be successfully treated with antibiotics, especially when treatment is initiated early in the course of the disease.
Prevention
Prevention is based on the control of this disease in domestic animals. People who work with animals that may be infected need to know the signs and symptoms of Q fever and seek treatment if they feel they could be infected.
Data and Statistics
A documented cluster of Q fever in Florida occurred during 1999 in Alachua County among researchers exposed to an infected sheep. In response to this outbreak, Q fever was listed as a reportable disease.
As of September 2005, 13 confirmed and probable cases of Q fever have been reported in Florida.