By Aisha Dow
Cooling towers are being tested in Cheltenham after an outbreak of Legionnaires’ disease was detected in the south-east suburb of Melbourne.
Three people who had recently been in the area were hospitalised with the severe form of pneumonia, and one leading infectious diseases expert said the cluster could be “just the tip of the iceberg”.
“Normally the incubation period is about 10 days, but it can be up to 18 days,” associate professor Sanjaya Senanayake said.
Legionnaires’ disease spreads when people breathe in bacteria-laden particles, for example through mist created by large air-conditioning units or spas.
Senanayake, an infectious diseases physician with the Australian National University, said investigators would be looking at what the three patients had in common to help pinpoint the source.
He said previous outbreaks had been linked to hospitals and potting mix, while in 2000, more than 150 fell ill and four people died after Melbourne Aquarium cooling towers became infected with Legionella pneumophila bacteria.
Senanayake said once officials had established what sort of species of Legionella it was, they would have a clearer idea if the outbreak was soil-based or may have originated from a cooling tower.
Victorian Chief Health Officer Brett Sutton urged people who had been around Cheltenham since early May to be alert for symptoms.
“Legionnaires’ disease often presents with initial flu-like symptoms such as headache, fever, chills, muscle aches and pains, and coughs that may progress to an atypical chest infection, also known as atypical pneumonia,” Sutton said.
“Other symptoms may include confusion and diarrhoea. Some people with Legionnaires’ disease may also develop kidney impairment.”
Those particularly at risk of catching Legionnaires’ disease are smokers aged over 65, people with chronic lung disease and those who drink a lot of alcohol or have other conditions that have weakened their immune system.
Last year, a Sydney woman in her 60s died from Legionnaires’ disease and five other people were hospitalised after a cluster of cases linked to potting mix.
Senanayake said Legionnaires’ disease was similar to COVID-19 in that some people who catch it might have a very mild illness or no symptoms.
The disease was first discovered in the 1970s when dozens of people died following a convention in Philadelphia with war veterans, although it later became apparent there were earlier cases that weren’t recognised.
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