A cooling tower in Melbourne’s west is the likely source of a legionnaires’ outbreak that has been linked to the deaths of two people, Victoria’s chief health officer says.
Over the weekend, the health department confirmed a man in his 60s died after being diagnosed with legionnaires’ disease during an outbreak in Melbourne’s west and north-west. As of Monday evening, 78 confirmed cases and 10 suspected cases had been reported to the department.
On Monday, the state’s chief health officer, Dr Clare Looker, said the department was confident that a cooling tower in Laverton North, in Melbourne’s west, was the likely source of the outbreak.
She said it was a “big site”, noting cooling towers were typically found in workplaces and shopping centres, but did not provide further details about the tower’s location.
Looker said it was a “preliminary result” and further work would be conducted to determine the amount of legionella in the sample. The department would also undertake whole genome sequencing to compare the sample from the site and samples from human cases.
She also said the department believed the peak of the outbreak had passed, with a significant reduction in daily reported cases compared with early last week. Most of the cases were people aged over 40, and nearly all had been hospitalised.
Looker said the Laverton North site was visited on 30 July and subsequently disinfected within 24 hours. It later returned a positive legionella sample.
“This gives us increased confidence that we have identified and already treated the source of this outbreak,” she said.
Looker said the operator of the site had “very good compliance” with health and safety protocols in the past, including a risk management plan to control legionella growth. She said investigations would continue at the site to understand what caused the outbreak.
Since the outbreak was identified last month, the department had visited and disinfected at least 54 sites.
“These visits continue as we speak. The speed and rigour of this investigation meant we were able to get on top of this outbreak quickly and limit any potential risks to the public,” she said.
Legionella is commonly associated with plumbing fixtures, humidifiers, air scrubbers and air conditioners but can become severe when it begins in a major water source.
The outbreak began on 26 July and marks the state’s worst in more than two decades.
