Definition of Q fever:

Q fever is a bacterial infection that can affect the lungs, liver, heart, and other parts of the body.

Causes, incidence, and risk factors:

Q fever is found around the world and is caused by the bacteria Coxiella burnetii. The bacteria affects 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

Chronic Q fever develops in people who have been infected for more than 6 months without effective treatment.

People at highest risk include those with heart valve problems or weakened immune systems.