A second person has died from legionnaires’ disease in Melbourne, as the outbreak grows to 77 cases over the weekend.

According to the Victorian chief health officer, Dr Clare Looker, a man in his 60s and a woman in her 90s are the two people who have died.

Dr Looker said on Sunday morning that the speed of the outbreak may be slowing down.

“We’ve definitely seen a decrease in the speed with which notifications are coming in and definitely a clustering of those symptoms and onsets from those earlier dates,” she said.

Victorian health authorities have narrowed down the cause of the outbreak to cooling towers in the Western suburbs of Laverton North and Derrimut. Dr Looker says that cooling towers are the most common source of legionnaires’ outbreaks.

“The information we have to date suggests the source of the outbreak is likely linked to one cooling tower in the area,” she said.

Health authorities have carried out tests on 54 of a hundred cooling towers in the area and are requesting test results from others across Melbourne.

Of the remaining 75 cases, all have been hospitalised.

The Department of Health is urging anyone who displays symptoms to seek medical care.

Legionnaires’ disease is caused by the bacteria Legionella, which is commonly found in natural water bodies and warm water systems, such as spas and cooling units. The disease spreads through breathing in fine droplets of water and is not usually spread from person-to-person. Symptoms usually present similarly to a chest infection, with fever, chills, cough, headache and muscle pains.

The Department of Health says adults over 40, smokers, and those with weakened immune systems and underlying medical conditions are at the highest risk of infection.

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