Legionnaire's can be caught by inhaling contaminated water

The woman works at the national headquarters of the Royal National Lifeboat Institution in Poole, Dorset.

Emergency checks of air conditioning and water systems are now being carried out at the office, where 480 staff work.

The woman was taken to hospital after suffering breathing difficulties, although it is not yet known how she caught the illness.

Legionnaires' disease, also known as Legionellosis, is a rare form of pneumonia.

It takes its name from the first known outbreak which occurred in a hotel that was hosting a convention of the Pennsylvania Department of the American Legion in 1976.

The disease is fatal in about 5-15% of cases.

It is most often contracted by inhaling mist from water sources such as whirlpool baths, showers and cooling towers which are contaminated with Legionella pnuemophila bacteria.