NSW Health has announced 'in principle' support for new measures to strengthen current cooling tower regulations to reduce future outbreaks of Legionnaires’ disease.
The new measures include the introduction of risk management plans for the operation of cooling towers. 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 early 2017.
The announcement follows the release of an investigative report into two Legionnaires’ disease outbreaks in Sydney’s CBD earlier this year which 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.
“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," Dr Chant said.
“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 also included the establishment of an Expert Panel to advise the Ministry on whether 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," Dr Chant said.
“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."
The City of Sydney Council has some 1200 registered cooling towers in the CBD. Systems regulated under the Public Health Act include air handling systems, hot water systems, humidifying systems, warm water systems and water cooling systems.
Earlier this month Hydrochem hosted a series of technical briefings on how to manage Legionella with the keynote address presented by water hygiene expert, Clive Broadbent.
Broadbent is the chair of AS/NZS 3666 (Air-handling and water systems of buildings - Microbial control) and is one of the world's foremost authorities on the control of Legionella bacteria.
Broadbent supports the introduction of risk management plans but said its important for them to be performance-based.
"The current one-size-fits-all approach doesn't suit everyone," Broadbent said. He outlined a multi-barrier approach to risk covering five categories - stagnant water, nutrient availability, poor water quality, system deficiencies, location and access.
A special report into the findings presented by NSW Health will be published in the next edition of CCN Magazine.
A summary of the public health investigation into both outbreaks can be found at:
http://www.health.nsw.gov.au/Infectious/Publications/legionella-cbd-report.pdf