What is the issue?
The Department of Health and Human Services has recently identified five cases of Legionnaires’ disease involving individuals who have spent time in the eastern half of Melbourne’s CBD and/or Southbank. All five required treatment in hospital. All had onset of symptoms within a similar timeframe between late March and early April 2017.
There have been a total of 26 cases of this type of Legionnaires' disease notified from across Victoria in 2017 to date, compared to 21 cases for the same period last year.
The department is investigating notified cases of Legionella infection to identify the possible source of their illness. A number of cooling towers in the CBD and Southbank have been sampled and disinfected. There have been no positive results for Legionella in the tested towers to date, however some results are still pending. Precautionary disinfection is being conducted at a large number of cooling towers in the eastern half of the CBD.
Who is at risk?
People aged over 50, smokers, heavy drinkers, people with diabetes or chronic lung disease and those with an impaired immune system are most at risk.
While those hospitalised spent time in the CBD and/or Southbank, their possible exposures have been across greater metropolitan Melbourne, so clinicians should consider testing for Legionella pneumophila in any patient with a compatible illness.
Symptoms and transmission
Legionnaires’ disease often presents with initial influenza-like symptoms such as myalgia, headache, fever and cough, and may progress to atypical pneumonia, sometimes with confusion. Rapid confirmation of the diagnosis of Legionella pneumophila serogroup 1, which makes up the majority of Victorian cases, can be obtained by urinary antigen testing. Sputum for culture should be sought in all cases if possible. A four-fold rise in titre between acute and convalescent sera is also diagnostic, however, this may take two to four weeks to develop.
Prevention and treatment
Early diagnosis and treatment with appropriate antibiotics is important in reducing the severity of illness and the risk of severe complications. Referral to hospital is often required for confirmed cases. Empirical treatment of moderate or severe community-acquired pneumonia (as per the current edition of the Therapeutic Guidelines) is recommended to cover Legionella bacteria.
- Legionnaires’ disease is a Group A notifiable condition which requires immediate notification to the department by telephone on initial diagnosis (presumptive or confirmed) with written notification to follow within five days.
- For further information or to notify a case please contact the Communicable Disease Prevention and Control Unit at the Department of Health and Human Services on 1300 651 160 or visit Legionellosis - Disease Information and Advice on the department's health website.
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health and Human Services on 1300 651 160 (24 hours).