NSW Health today released the findings of its investigation into two Legionnaires’ disease outbreaks in Sydney’s CBD earlier this year that resulted in 13 confirmed infections, including one death.

Two other patients diagnosed around the same time, including one patient who died, were found to have different strains and appear unrelated to the outbreaks.

NSW’s Chief Health Officer Dr Kerry Chant said the investigation for outbreaks in March and May 2016 used cutting-edge genome sequencing technology to link bacterial samples from patients with potential environmental sources of the infections.

“Legionnaires’ disease is a bacterial infection of the lungs that causes pneumonia. It can develop after breathing in contaminated water droplets or dust. Outbreaks of the disease are most frequently linked to contaminated water cooling systems of air-conditioning plants in large buildings,” Dr Chant said.

“While we cannot pinpoint the ultimate source of the outbreak, we were able to confine the origin of the bacteria to buildings in downtown Sydney west of Hyde Park between Park and Margaret Streets.

“Proving the exact source of the outbreak is often difficult as cooling towers may be cleaned even before they can be examined.

“The aim of a public health response is to stop the outbreak as soon as possible by ensuring that cooling towers and other possible sources of infection in a location suspected to be the cause of the outbreak are controlled as quickly as possible.

“As soon as each outbreak was reported, NSW health worked closely with City of Sydney Council staff to enforce remedial action in the likely source areas".

“This included precautionary cleaning of air-conditioning cooling towers in the immediate vicinity to successfully control the outbreaks.”

Dr Chant said the outbreak investigation involved collaboration between epidemiological, environmental, clinical and scientific experts from multiple agencies.

“It included careful interviews with patients or family members about their possible exposures, and a door-to-door search for potential sources of infection".

“NSW Health established a Legionella Expert Panel to advise the Ministry on whether any new measures are required to strengthen current prevention and control activities".

“While recognising that NSW already has a strong regulatory system for preventing Legionnaire’s disease, the Expert Panel recommended strengthening it by further developing risk management plans for the operation of cooling towers".

“This would include owners developing an individual monitoring and control plan for each cooling tower system with regular testing, inspection and auditing".

“NSW Health supports the recommendations in principle, but needs to conduct further consultation on the proposed changes,” Dr Chant said.

NSW Health will issue a consultation paper on the proposed changes in the coming weeks. Following a consultation period, it is expected that regulatory changes would be made in the first part of 2017.

A summary of the public health investigation into both outbreaks can be found at Summary - Public Health Investigation onto the Legionella Outbreaks in Sydney CBD.

For further information on Legionnaires’ disease visit Legionnaires' disease.