Four people in New York City's Harlem neighbourhood have died from an outbreak of Legionnaires' disease, an aggressive and potentially deadly form of pneumonia. The city has seen 99 confirmed cases with 17 people in hospital with the infection, according to the New York City Department of Health.

The Legionnaires' disease outbreak in Central Harlem has been traced to 12 cooling towers, including several at city-run buildings, officials said.