Legionnaires’ disease, also known as Legion fever, is a severe form of pneumonia caused by the Legionella bacteria, which is found in damp or wet environments with warm, stagnant water.

Legionnaires’ disease was first named in America in 1976 after 182 people fell ill, 29 of whom later died, while attending a convention of the American Legion in Philadelphia. The cause was later identified as a previously unknown strain of bacteria found in an air conditioning unit.

Along with cooling towers, pools, spas and fountains, air condition units are amongst the more common breeding ground for the Legionella bacteria.

Tens of thousands of people are estimated to get infected every year, and although most cases are not severe, up to ten per cent of cases can be fatal.

Most people who are exposed to the bacteria do not become infected, but the risk of disease increases with age. Smokers also run a greater risk of being infected, as do people with medical conditions that weaken the body’s immune system. It is rare for young people and children to become infected.

Here’s our Legionella Outbreaks Around the World interactive map for timely updates on outbreaks in Australia and abroad.