Published Date: 2012-05-25 12:11:59
Subject: PRO/EDR> Legionellosis - New Zealand (04): (AU) fatal
Archive Number: 20120525.1144719
LEGIONELLOSIS - NEW ZEALAND (04): (AUCKLAND) FATAL
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Thu 24 May 2012
Source: stuff.co.nz [edited]
An outbreak of legionnaires' disease in Auckland has claimed a 2nd life and infected 16 people. Legionnaires' is a form of pneumonia that can be life threatening for people with weakened immune systems.
In February  the Auckland Regional Public Health Service warned of an outbreak and began working with Auckland Council to encourage shock-dosing of all cooling towers and industrial water-cooling systems, in a region-wide effort to stop the disease spreading.
To 1 Apr 2012, 12 people had been infected and in March it claimed its 1st victim, an elderly woman who was already ill. Figures released under the Official Information Act yesterday [23 May 2012] show a further 4 people have been infected and another person has died. That person was also believed to be suffering from underlying health issues. The health service couldn't say where the deaths occurred because they don't record that information. A further 2 people contracted legionnaires' [disease] between January and February 2012 but their cases occurred before the outbreak. Typically one or 2 cases are identified in a 6-week period.
Those infected contracted the disease from a water source, which may include air conditioning systems in buildings, the health service said. It was believed more than 600 buildings shock-dosed their water-cooling systems following the health scare. However, the health service has been unable to establish a definite link between the cooling systems and the outbreak.
The health service believes the "warm, damp summer" period may have provided a breeding ground for the bacteria. "We thought of any situation where there would be old water droplets in the air and had to think outside the square," said spokeswoman Cathy McIntosh. In the past 27 days only one person had contracted the disease so if there are no further cases in the next fortnight health authorities will rule the outbreak is over.
The health service is trying to safeguard against future outbreaks, including working alongside the Department of Labour to test workplaces as potential sources of infection. "[The outbreak] has put a reminder in places to help people understand that they have a responsibility," McIntosh said.
Symptoms of legionnaires' can include headache, diarrhoea, dry cough, drowsiness, and delirium. It is treated with antibiotics, however, most people who contract the disease are hospitalised with pneumonia.
[When ProMED-mail last reported on this outbreak of legionellosis in Auckland, NZ (Legionellosis - New Zealand (03): (AU) fatal 20120425.1113122), there were a total of 15 cases, including one fatality; all were caused by _Legionella pneumophila_ serogroup 1. Now there are a total of 16 cases, including 2 deaths. Because there has been only one additional case in the past 27 days, if there are no further cases in the next fortnight health authorities will rule the outbreak is over.
Contaminated water has been hypothesized as the source rather than contaminated potting mix, because _Legionella pneumophila_ serogroup 1, a waterborne pathogen, was incriminated in all cases rather than _Legionella longbeachae_, a species that is commonly found in potting mix, compost, and soil and cultured from the respiratory specimens in patients with community-acquired pneumonia associated with gardening and exposure to potting mix and compost, especially in Australia and New Zealand.
We still do not have information concerning genotyping of _L. pneumophila_ isolated from patients in the current outbreak. A single genotype would suggest a common source, and could be matched to any environmental isolates. Frequently, however, if the diagnosis of legionnaires' disease is made only on the basis of urinary _L. pneumophila_ serogroup 1 antigen testing or serology, rather than isolation of the organism from cultures of respiratory tract specimens, genotyping of clinical isolates would be not, of course, possible.
The Auckland region is on the North Island; it is one of the 16 regions of New Zealand, with a population of almost 1.5 million (one third of the nation's residents) in 2011, and is the country's largest urban area, which encompasses the Auckland metropolitan area, smaller towns, rural areas, and the islands of the Hauraki Gulf (http://en.wikipedia.org/wiki/Auckland_Region). The Auckland Central Business District is densely built-up, with high-rise buildings mainly used for commercial and retail uses, although there are residential high-density buildings and a population of about 40 000 residents (http://en.wikipedia.org/wiki/Auckland_CBD).
The HealthMap/ProMED-mail interactive map of New Zealand can be accessed at http://healthmap.org/r/1VY-. - Mod.ML]