What is the issue?
The Department of Health has recently identified three cases of Legionnaires' disease involving three individuals who all live or have spent time in the Altona North area. All three required hospital treatment. All had onset dates within a similar timeframe during April and early May.
These three cases are in addition to six cases identified in the western suburbs of Melbourne this year. There have been a total of 15 cases of this type of Legionnaires' disease notified from across Victoria to date, compared to 23 for the same period last year.
The Department is continuing to investigate these cases and identify the possible source of their illness. The cooling towers in the area have been sampled then disinfected as a precaution. They will continue to be monitored, but the test results from all the sampling is not expected for several days.
Who is at risk?
People aged over 50, heavy smokers, heavy drinkers, diabetics, people with chronic lung disease and those with impaired body defences are most at risk.
While those hospitalised spent time in Altona North, their possible exposures have been across greater metropolitan Melbourne, so clinicians should consider testing for Legionella pneumophila in any patient with compatible testing illness.
Symptoms and transmission
Cases typically present with influenza-like symptoms such as headache, fever, rigors, cough or myalgia, and may progress to atypical pneumonia 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.
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 Therapeutic Guidelines) is recommended to cover Legionella bacteria.