What is Q fever?

Q fever is a widespread disease caused by the intracellular bacterium Coxiella burnetii, which is able to infect mammals, birds, reptiles and arthropods. It causes a mild disease in ruminants, but can cause abortions and still births in cattle, sheep and goats. Clinical cases seem to be most significant in sheep and goats, with sporadic losses and occasional outbreaks that may affect up to 50-90% of the herd.

Any infected animal has the potential to transmit the pathogen via bacterial shedding in their body secretions. Human outbreaks and cases have been epidemiologically linked to exposure to multiple species including pigeons, dogs, and rabbits. Human cases and outbreaks linked to exposure to infected parturient cats also have been reported.

Aerosolized organisms from these animals are sometimes spread by the wind, occasionally travelling long distances. Windborne outbreaks can affect dozens to hundreds of people who have no direct exposure to animals.

First identified in Australia in 1935, Q fever has since been found throughout the world with the exception of New Zealand. Symptoms of Q fever include fever, chills, night sweats, headache, fatigue and chest pains. Pneumonia (lung infection) and hepatitis (inflammation of the liver) can occur in serious cases.

In pregnant women, infections can cause premature delivery, abortion and infection of the placenta. In people with pre-existing heart valve disease, endocarditis (inflammation of the heart valves) may occur.
What is Q fever?