Cooling tower is suspected as source of legionella outbreak

BMJ 2012; 344 doi: (Published 07 June 2012) Cite this as: BMJ 2012;344:e3985
  1. Bryan Christie
  1. 1Edinburgh

An industrial cooling tower is thought to be the source of an outbreak of Legionnaires’ disease in Edinburgh that has killed one man and left another 15 people critically ill.

There are an additional 15 suspected cases and more are expected to be identified over the coming days.

Four towers have been chemically treated in an attempt to kill the bacteria since the first case was detected on 28 May. Symptoms can take between two days and two weeks to appear after exposure to the legionella bacterium.

Although the source of the infection has not been traced, suspicion has centred on cooling towers in the south west of the city, where most of the confirmed cases are concentrated.

Duncan McCormick, a public health consultant who is chairing the incident management team, said: “Investigations into the possible source of this outbreak are on-going. Meanwhile, medical staff have been actively identifying possible cases to allow us to ascertain the full extent of this outbreak.”

Samples from the cooling towers are being tested to see if they are the source, but results are not expected for several more days. This might also prove inconclusive as investigations often do not find the source.

The man who has died was in his 50s and had underlying health problems. The other confirmed cases are in two women and 13 men, aged between 33 and 74, who are all being treated in hospital. One man, having recovered, has been sent home.

McCormick said: “Older people, particularly men, heavy smokers, and those with other health conditions, are at greater risk of contracting the disease.”

The biggest legionella outbreak in the UK happened in 2002 in Barrow-in-Furness, Cumbria. A contaminated cooling tower at an arts centre was the source of that outbreak. A total of 172 people were affected, and seven died as a result of the illness.


Cite this as: BMJ 2012;344:e3985