Doctors on lookout after Legionnaires outbreak

GPs are on the lookout for more cases of Legionnaires' disease after an outbreak of the potentially lethal illness in Christchurch.

One man has died of the disease and another eight men are hospitalised.

Canterbury medical officer of health Mel Brieseman said someone with the disease would be suffering from pneumonia, with a chest condition.

"We have asked all general practitioners who may be treating patients at home with pneumonia to consider the possibility of Legionnaires' disease and have them tested," he said today.

The younger man who died had been one of two cases in June, while the other eight cases had been last month.

"We're uncertain of connections between those two groups, or indeed within the last eight. That's what we're investigating," Mr Brieseman told National Radio.

The cases were "scattered around a bit and this is one of the confusing features".

"It would be nice...if we were able to say they all attended one club, or had been to one hotel or something of that sort of nature. But that's not the situation.

"So we are currently investigating to see whether there are connections between them which would point to a source."

The disease could be spread through anything that sprayed water, including such sources as cooling towers, fountains, road sprays, even home showers, Mr Brieseman said.

"If there is a common source that's continuing there are likely to be more cases and we'd like to get rid of it."

Healthy people were at less risk of catching the disease, and it did not spread from person to person.

Of the eight people still with the illness, all are elderly men with an average age of 80. Mr Brieseman said he understood they were recovering.

Four of the legionellosis cases were diagnosed in a single week.

Normally up to five isolated cases of the lung disease are recorded in Christchurch each year, but clusters are rare.

The city's last outbreak -- and the first recorded in the country -- was in 1990 when it was discovered in the Ministry of Transport's Kilmore St headquarters. An infected air conditioning system caused two confirmed cases of the disease and up to five others.

Legionnaires' disease, first identified in the United States in 1976, is most common in people aged over 50. Males, smokers and heavy drinkers are most at risk.

Up to 80 cases are reported to New Zealand health authorities annually, including a few deaths. Internationally, the death rate is between 5 per cent and 30 per cent of cases.

- NZPA