William Ton, AAP
Melbournians are being urged to monitor for symptoms after a significant outbreak of legionnaires’ disease left several people critically unwell in intensive care.
At least 22 cases of the bacterial disease have been confirmed and six suspected since Friday stemming from areas across metropolitan Melbourne, especially in the north and west, Victorian Chief Health Officer Clare Looker said.
Most of the cases have occurred in adults aged over 40 and have required hospitalisation resulting from severe community-acquired pneumonia.
“This is a nasty type of pneumonia … so people can become quite sick quite quickly,” Dr Looker told ABC Radio Melbourne on Tuesday.
“Most of our cases at the moment are in hospital, a number in ICU … so they’re critically unwell.”
Those with underlying diseases, particularly people who are immunocompromised, elderly people and smokers are at greater risk of infection.
Typically, there would be three to six cases a week but the high number of reported cases in the past four days has left authorities concerned.
Anyone who has visited or lives in metropolitan Melbourne and develops symptoms including chills, fevers, a cough, or feeling unwell has been urged to seek medical attention.
While the source of the disease remains unknown, investigations are underway to test local cooling towers and other potential sources.
Legionnaires’ disease is caused by the legionella bacteria and tests indicate the outbreak is caused by legionella pneumophilia serogroup 1.
The bacteria is found in natural bodies of water such as rivers, lakes, creeks and hot springs but can also be found in spas, warm water systems and artificial systems that use water for cooling, heating or industrial processes such as cooling towers and potting mix.
“You can’t get person-to-person transmission,” Dr Looker said.
“Typically, people will almost always get it by breathing in fine droplets of water that contain the bacteria.
“Most often we will see most of the big outbreaks are associated with cooling towers so big industrial air conditioners.”
Investigations suggest the outbreak is likely from a single source and Dr Looker expects a wave of cases before it diminishes.
