Six cases of legionnaires’ disease have been detected in Sydney’s CBD and a health alert has been issued.

Legionnaires’ disease is a severe form of pneumonia that develops when a strain of bacteria named Legionella pneumophila infects the lungs. The bacteria isn’t spread from person-to-person, but through aerosols and can take between two to ten days to develop following exposure.

According to the Australian Bureau of Statistics, more than 500,000 people work in the CBD as the City of Sydney works to investigate cooling towers.

“When we see a cluster of new infections like this, we often find that there’s a cooling tower that’s contaminated with the bacteria,” NSW Health South Eastern Sydney Local Heath District Public Health Unit director Vicky Sheppeard says.

“We’re actively taking steps to identify that tower and have it cleaned so other people don’t become ill.”

Plumbing professionals can prevent the spread of water-borne diseases like legionnaires, dysentery, cholera and Hepatitis A.

Ensure buildings are regularly reviewed, especially if there are cooling towers, and contractors working with hot and cold water systems, including spa fountains and misting systems.