COMMUNICATIONS

Media Release - 01/09/2005

Clear Lessons to be Learnt from Outbreak of Legionella in Christchurch

The Canterbury District Health Board has today completed its checks on more than 80% of the cooling towers in Christchurch. The results show that the public risk following the recent outbreak of Legionnaires Disease has now been effectively dealt with.

Medical Officer of Health Dr Alistair Humphrey said 139 cooling towers had been tested with 115 confirmed results.

‘The results show that there are now no towers with results above 100 colony infecting units (cfu) which is well below the 1000 cfu considered to be dangerous.

Dr Humphrey said that when the Health Board started its checking regime shortly after the outbreak earlier this year, four companies volunteered positive results. Only one of the four had a result that showed the same strain of legionella that had been discovered in the people who had been diagnosed in this outbreak. This was a cooling tower located close to the centre of the disease cluster.

‘The company contacted us as soon as they had their results and were very quick to advise their staff and immediately take the remedial action we recommended.’

‘In doing so, they acted very responsibly and we commend them for being so prompt even though the high readings they had did not correspond with the outbreak of the disease.’

Dr Humphrey said there were clearly lessons to be learnt from the outbreak in Christchurch, which had seen 19 people diagnosed with Legionnaires Disease and resulted in three deaths.

‘Our concern has always been for public safety, and we have been working with the cooling tower testing companies, the laboratories who test for results, the City Council and other members of the industry sector to look at what protocols can be introduced to prevent the spread of Legionnaires Disease from cooling towers. This is important not only for Christchurch but for any other city in New Zealand.’

Dr Humphrey said it had taken several weeks to get the test results and during that time the Health Board had conducted a scientific study interviewing the people diagnosed with Legionnaires Disease and the families of those who died, as well as others of similar age and gender to get a more informed opinion of what had happened.

‘The study demonstrated a probable spatial relationship between the main cluster of people with the disease and the location of a single high result last April. Unfortunately, many companies did not test their cooling towers around the time of the outbreak including the one that had the high result.’

Dr Humphrey said that the DHB would get the results back from all the 139 cooling towers in Christchurch and he and his team would continue to work closely with the City Council to get these as soon as possible.

‘The last case of Legionnaires Disease was notified on 16 August and as times goes by we are increasingly confident that this outbreak is over.’

Ends.

Please note there is no further comment at this time.

Vivienne Allan
Communications Manager
0275-314-796