LONDON -- Legionnaire's disease has killed an 89-year-old man and infected at least 18 other people as British health authorities were bracing for an outbreak of the illness.

More than 100 people in Northern England are suspected of having contracted the bacteria, which is often spread through large air conditioning systems and thrives in warm, moist environments.

All of the infections were in Barrow in northwest England. The disease is usually treatable, but can be deadly for the elderly or other people in a weak physical condition.