MEDIA RELEASE
FOR IMMEDIATE RELEASE

11 July, 2012

Legionella outbreak is over

Legionella pneumophila (Lp1) notifications in the Auckland region have returned to the normal background rate of 0-2 per month with only two confirmed cases in the last 78 days, indicating that the recent outbreak is now over.

There was a total of 17 confirmed cases between February and July 2012. Regretfully the disease was a contributing factor in the deaths of two people during this time.

Investigation into the spread of the outbreak did not result in defining a source. It is possible that there were multiple sources, given the wide geographic scope of cases. 

Auckland Regional Public Health Service (ARPHS) and Auckland Council worked together to raise awareness and search for the source of the bacteria.

The council made contact with the owners of over 600 buildings containing cooling tower. A large number of these cooling towers are associated with manufacturing processes and as such are excluded from the council’s regulatory oversight.

Building owners were advised to shock-dose their cooling systems and test for the presence of Legionella after three to seven days as a precaution and then register their compliance with the council.

Medical Officer of Health, Dr Simon Baker, says the outbreak increased awareness of risks and the need for improved surveillance of vulnerable water systems.

“Legionella bacteria occur naturally in the environment and can reach levels dangerous to people. The Lp1 sub-species is commonly found in warm water systems. This outbreak indicates that maintaining cooling tower surveillance and treatment is of paramount importance. Any systems that use stored water without heating or cooling sufficient to kill bacteria, need to be carefully monitored for Legionella presence, and treated if necessary,” Dr Baker says.

In addition to shock-dosing, the onset of lower autumn/winter temperatures may have helped reduce the opportunity for Legionella survival and replication.

Auckland Council building control manager Ian McCormick says that vital knowledge and experience was gained during the outbreak. ARPHS has added the locations of all known cooling towers to their GIS database.

“Having more complete knowledge about the locations of cooling towers in the region will allow the public health team to identify and contain specific locations more quickly, if a new case is reported,” says Mr McCormick.

An inter-agency working party has formed to review the handling of the outbreak. It includes the building control and public health teams, as well as a number of other key industry groups such as the Property Council, Department of Labour, Department of Building and Housing and the Manufacturers and Exporters Association.

Mr McCormick says the group is likely to advocate for legislative changes, to make it mandatory for building owners to log their cooling towers on a register, and to require owners to test for the presence of Legionella every month.

ENDS

Auckland Regional Public Health Service
Cathy McIntosh
Cell: 021 243 2421
Email: cathymc@adhb.govt.nz

Auckland Council
Charlotte Haycock
Cell: 027 297 4966
Email: charlotte.haycock@aucklandcouncil.govt.nz