Q fever is a disease that spreads from animals to humans (zoonosis). It is caused by a bacterium called Coxiella burnetii. This microorganism can live in its spore form for months and even years in dust or soil. It is found all over the world. 

Animals like goats, sheep and cattle can carry the Q fever bacteria in their flesh and body fluids. The highest levels of these bacteria are found in tissues involved in birth - the uterus, placenta, and birth fluids. People usually get infected by breathing in dust contaminated by these tissues. 

The droppings of insects and spiders infected with Q Fever have high levels of this microorganism. It may also be present in raw or unpasteurized milk from infected animals.  

Most of the time, Q fever is mistaken for an acute viral illness. If someone is infected, symptoms appear in 2 to 3 weeks (range 3 to 30 days). The symptoms include:

• rapid onset of fever
• chills
• headache
• weakness
• malaise (a general sick feeling), and
• severe sweats

People usually get Q fever when they breathe in dust contaminated with coxiellae. It is very infectious, and only a very few microorganisms can cause infection. 

Infection can occur through direct contact with infected animals and contaminated materials. People may also get Q fever by drinking unpasteurized infected milk. It rarely, if ever spreads from person to person.    

Q fever spreads around farming areas, and can affect anyone who works outdoors and is in contact with infected soil or dust. Airborne Q fever bacteria may be carried a long way downwind - one kilometre or more. Q fever also spreads from room to room easily in farm buildings and laboratories housing infected animals.     

Some people at higher risk for Q fever include:

• farmers
• ranchers
• farm workers in contact with goats, sheep and cattle, particularly during the birthing process
• stockyard workers
• livestock truck drivers
• personnel who service the trucks
• visitors to animal auctions
• meat packers
• rendering plant workers
• hide and wool handlers
• hunters and trappers
• animal researchers and support staff
• workers who care for pets and livestock - veterinary personnel, and zoo attendants
• certain medical and health care people who have contact with blood, spit or tissue from infected people

In most cases, the illness lasts less than two weeks, and does not require special medical treatment. Complications of this disease are rare and are more likely to happen with people who have weakened immune systems, including pregnant people. These complications include:

• inflammation of the lungs
• miscarriage
• neurologic problems
• inflammation of the heart

Most people who get Q fever get well without any special medical treatment. The fatality rate for untreated cases is less than one per cent. However, in a very few cases a patient can develop hepatitis or liver disease and jaundice, a yellowing of the skin and darkening of the urine. In these cases, antibiotics are used to treat Q fever.

Diagnosis of Q fever is done in a few different ways:

• detection of antibodies
• detection of Coxiella burnetii in blood or tissue
• detection of C. burnetii DNA in a PCR test

The attending physician will know when to prescribe antibiotics for the treatment of Q fever.