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 five zip codes where the cluster of cases are located are 10027, 10030, 10035, 10037 and 10039. Additionally, 12 cooling towers have tested positive for live bacteria in 10 buildings. Eleven of these towers have been sanitized and treated, and the last will be completed on Aug. 15.

NEW YORK -- A fourth person has died in connection with a Legionnaires’ disease outbreak in New York City, health officials disclosed Thursday as they revealed that some cooling towers that tested positive for the bacteria are in city-run buildings.

Announcement of the latest death comes just hours after city officials identified 12 cooling towers in 10 Harlem buildings that tested positive for Legionnaires' disease.

Health officials in New York City say an outbreak of Legionnaires’ disease in Central Harlem has grown to 90 cases, including three deaths.

Fifty-eight people have been infected—and two have died—in a New York City outbreak of Legionnaires’ disease—a severe type of pneumonia caused by a bacterium commonly associated with air-conditioning

Here’s what to know about water-cooling towers amid a cluster of Legionnaires’ disease cases in Central Harlem.