About Legionnaires' Disease

Legionnaires' Disease was first detected internationally in 1976 and in Victoria in 1979.  Victoria currently averages around 150 cases per year.  Legionnaires' Disease is mainly contracted by breathing in water droplets that are contaminated with the bacteria Legionella.  Legionella bacteria occurs naturally in the environment in water and soils.

Man-made systems such as cooling towers and warm water systems can provide the perfect environment for Legionella to multiply.  In particular, cooling towers maintain a water temperature of the water of approximately 250C, which is optimum for Legionella growth.

Cooling towers operate by passing air through water.  During this process, aerosols can form that can be transmitted through the air to humans.  If the cooling tower water (and hence the aerosols) contain Legionella, people can become infected.  Those most at risk include smokers, the elderly, heavy drinkers and those with chronic diseases.

Symptoms of Legionnaires' Disease include shortness of breath, fever, headaches and general aches and pains.  Approximately 5% of cases are fatal.  Legionnaires' Disease takes between 2 and 10 days to develop and is usually detected by a urine test.