What is the issue?
The Department of Health & Human Services has seen an increase in cases of Legionella infection notified this year. There has been a total of 47 cases of Legionella infection notified from across Victoria in 2017 to date, compared to 28 cases for the same period last year.
The department is investigating notified cases of Legionella infection to identify the possible source of their illness. An outbreak has been identified in the Cranbourne area, where there have been 4 cases since February who have visited the Cranbourne Shopping Centre during their incubation period. Although there are no cooling towers at the shopping centre, a number of cooling towers have been identified in the vicinity and have been sampled and have undergone precautionary disinfection. There have been no positive results for Legionella in the tested towers to date, however some results are still pending.
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.
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 the Infectious Diseases section on Legionnaires’ disease.
For more information please contact the Communicable Disease Prevention and Control section at the Department of Health & Human Services on 1300 651 160 (24 hours).