Recommendations after fatal legionella outbreak

An outbreak of legionella that killed three Christchurch people in the winter of 2005 has prompted a raft of recommendations from a coroner.

During an inquest held in Christchurch last year, Southland-Central Otago Coroner Trevor Savage heard evidence from health officials, scientists, building experts, local body officers and company executives.

Ross Hern, 56, Peter Jones, 48, and Valmai Finlayson, 87, died of legionnaires' disease in Christchurch Hospital in June, July and August 2005.

Their deaths followed an outbreak of 19 legionella cases clustered in southwest Christchurch, an outbreak compared by experts giving evidence at the inquest to some of the worst worldwide in the past few decades.

Attention focused on a water cooling tower at the Ravensdown fertiliser plant in suburban Hornby as a possible source of the disease -- a serious and sometimes fatal form of pneumonia.

However, in the inquest findings just released Mr Savage accepted it was impossible to pinpoint the source of the infection which each of the three deceased contracted.

"I further hold that the evidence does not support a conclusion that the Ravensdown tower was the probable source of the infections contracted by any of the 19 persons who were infected and that it is impossible on the evidence to conclude what was the source of the infections of any of those 19 persons," Mr Savage said.

Echoing a statement given at the inquest by Roderick Dickson, a senior Labour Department occupational health scientist, Mr Savage said the hazard of legionella was "so significant and potentially far-reaching" that comprehensive protection should be offered to the public.

Widely distributed in lakes, rivers, groundwater and soil, legionella species are generally benign until aerosolised. They are associated with outbreaks linked to poorly maintained hot water systems, water cooling towers or evaporative condensers and water spraying devices such as fountains and water sprinklers, demisters and spa pools.

Canterbury Medical Officer of Health Alistair Humphrey told the inquest that current building regulations were "inadequate" in detecting legionella and protecting the public.

Building owners, he told the coroner, were legally required to test for legionella in their air conditioning systems, but did not have to tell health authorities if the tests revealed high levels of disease-causing bacteria.

Dr Humphrey gave evidence that the lack of a mandatory system seriously impeded health authorities searching for the source of the 2005 outbreak.

Mr Savage said he found the current regulatory regime governing water cooling towers was "clearly unsatisfactory" and could be improved by a "few simple steps that would not be costly".

He acknowledged that further consultation with affected parties, such as employer and employee organisations, territorial authorities, district health boards, commercial building owners and relevant government departments and ministries, may be desirable.

Mr Savage also noted that a wider cost-benefit analysis might also be warranted and that the application of any proposed regulatory changes to other warm water systems, such as public swimming and spa pools, should be considered.

In recommendations addressed to the Ministry of Health and district health boards, he urged that:

* The legionellosis case definition for New Zealand be reviewed in light of testing methods now available.

* Appropriate samples be collected for legionella culture and testing from suspected legionellosis cases and forwarded to the Legionella Reference Laboratory for national surveillance of the disease.

* District health boards, if they have not already done so, consider including the urinary antigen test in the ranges of tests for legionellosis.

Mr Savage also recommended the Government consider legislation or regulatory amendments so that:

* Cooling tower owners or operators are required to register their towers with local authorities.

* Territorial authorities create and maintain a single database of all cooling towers for hating and ventilating systems.

* All cooling towers are brought into the compliance schedule or building warrant of fitness regime administered by local authorities.

* Cooling towers are classified as a separate class of specified system in the building warrant of fitness regime.

* It is mandatory for all new and existing cooling towers to comply with Australian and New Zealand standards.

* Testing for legionella is done at least monthly.

* Laboratories are required to notify high legionella test results.

* Local authorities and medical officers of health are given powers to audit testing and ensure corrective action is taken.

NZPA