The Victoria Department of Health and Human Services has recently identified five cases of Legionnaires’ disease (Legionella pneumophila, serogroup 1) involving individuals who have spent time in the eastern half of Melbourne’s Central Business District (CBD) and/or Southbank.

Legionella pneumophila bacteria/CDC
Legionella pneumophila bacteria/CDC

All five required treatment in hospital. All had onset of symptoms within a similar timeframe between late March and early April 2017.

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.

Legionnaires’ disease is caused by Legionella bacteria and can cause severe pneumonia. Individuals with underlying health problems such as chronic lung disease (like chronic obstructive pulmonary disease or COPD, or emphysema) and people with weak immune systems from diseases like cancer, diabetes, or kidney failure are more likely to develop severe disease.

Symptoms of Legionnaires’ disease include cough, fever, difficulty breathing, muscle aches and headaches. Sometimes patients will have diarrhea, nausea and confusion.

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 bacteria that causes Legionnaires’ disease was first identified in 1976 when people attending an American Legion convention in Philadelphia developed pneumonia. The source of that outbreak was determined to be the contaminated air cooling system in the hotel where the convention was being held.