Four cases of Legionnaires' disease have been confirmed in Adelaide in the past week, prompting a call by health authorities for checks of air conditioning cooling towers.
SA Health says the source of each case, all involving men aged 37 to 71, has not been identified.
The men are being treated in hospital but have not reported attending a single common location within the incubation period.
The outbreak could be the result of fluctuating temperatures over recent weeks which prompts the growth of Legionella bacteria in air conditioning cooling towers.
Chief Public Health Officer Kevin Buckett said businesses should decontaminate their air conditioning systems.
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"Ongoing maintenance of water and cooling systems significantly reduces the risk of the Legionella bacteria growing," Dr Buckett said.
"This is why it is important that proper preventative maintenance and anti-microbial treatment is carried out, particularly in times of variable weather."
Legionnaires' disease is contracted by breathing in the bacteria but is not passed from person to person.
The resulting respiratory illness can bee particularly dangerous to the elderly, smokers or those with compromised immune systems.
