Australia: Legionnaires' disease cluster in Sydney
7 people infected after visiting the Sydney CBD
As of January 3, health officials in New South Wales state (NSW Health) in southeastern Australia are advising people who have been in the Sydney Central Business District (CBD) area in the past 10 days to be on alert for symptoms of Legionnaires’ disease after seven people who have developed the disease spent time in the area in the last three weeks.
According to officials, the seven people, three women and four men, ranging in age from their 20s to 70s, independently visited locations in the CBD between Bathurst Street, Sussex Street, Elizabeth Street and Circular Quay in the 10 days prior to their symptoms. All have been admitted to hospital for treatment of pneumonia.
All seven people have been identified with the Legionella bacteria that causes Legionnaire’s disease, which is often associated with contaminated cooling towers of large buildings.
NSW Health environmental health officers are working closely with the City of Sydney Council to inspect cooling towers. Review of maintenance records of cooling towers in the CBD area will also help determine further towers to be inspected and sampled.
Managers of buildings with cooling towers are being contacted and informed of the cluster. Building owners should ensure that their cooling towers are operated and maintained in compliance with the NSW Public Health Regulation 2022.
Dr. Marc Edwards and Sarah Ferrari—Legionnaires’ disease and Legionella, Part One
According to the World Health Organization (WHO), legionellosis is an infection caused by Legionella bacteria. The Legionella bacteria can cause a mild illness, Pontiac fever, non-pneumonic form of the disease, and Legionnaires’ disease, a severe pneumonia form of illness that can be fatal. Most people catch Legionnaires' disease by inhaling the bacteria from water or soil.
Legionnaires’ disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days have been recorded in some outbreaks). It is an important cause of community- and hospital-acquired pneumonia, and although uncommon, Legionnaires’ disease may cause outbreaks of public health significance. Initially, symptoms are fever, mild cough, loss of appetite, headache, malaise and lethargy, with some patients also experiencing muscle pain, diarrhea and confusion. The severity of Legionnaires’ disease ranges from a mild cough to rapidly fatal pneumonia. Untreated Legionnaires’ disease usually worsens during the first week.
Mortality from Legionnaires’ disease depends on the severity of the disease, the use of antibiotic treatment, the setting where Legionella was acquired, and whether the patient has underlying conditions, including immunosuppression. The death rate may be as high as 40–80% in untreated immunosuppressed patients and can be reduced to 5–30% through appropriate case management, depending on the severity of the clinical signs and symptoms. Overall, the death rate is usually between 5–10%.
