Major Legionnaires' outbreak in Cumbria

Cases of the disease have been confirmed

Dozens of people may have potentially lethal Legionnaires' disease, a Cumbrian hospital has confirmed.

And the search is on to find the source of the infection before dozens more fall ill.

At present, 19 cases have been confirmed and another 11 are suspected in Barrow-in-Furness.

However, the incubation period of the disease means that experts estimate as many as another 100 cases could arise over the next two to three weeks.

The infection is fatal in up to 15% of cases.

The source of the infection has not yet been determined. All the patients come from Barrow.

A major incident team has been set up in Barrow to handle the outbreak, with Morecambe Bay NHS Trust on alert to deal with more cases.

Air conditioning

The disease is caused by the Legionella bacterium, and is often spread through colonised air conditioning units.

This is why outbreaks often happen in the summer months.

There is an incubation period of several days between infection and the onset of symptoms.

At first, these are flu-like, followed by fever and chills, then a dry cough develops.

The worst-affected patients often have great difficulty in breathing, and hospitalisation is always required.

Antibiotics are used to treat it, and this can take several weeks.

Major outbreaks

The disease was first identified following an outbreak at a hotel hosting a conference of the American Legion organisation in 1976 - this gave the illness its name.

The first cases of Legionnaires' in this country were spotted in 1977 - but this was followed by a series of major outbreaks in the UK linked to infected water cooling systems.

An outbreak in Stafford in 1985 affected 68 people - of whom 23 died.

Two outbreaks in central London in 1988 - centred on the BBC - affected 79 people, with three deaths.

To date, the world's largest outbreak was in Murcia, Spain, with over 500 confirmed cases.

Increased vigilance and safety checks on water cooling and air conditioning systems has cut the number of cases in recent years.

However, scientists warn that climate change could lead to a higher rate of outbreaks in future.