A Legionnaires' disease cluster in the Harlem area of New York City has caused four deaths and sickened over 100 people. Here's what it is, symptoms and how it's spread.

Health officials in New York City say a cluster of Legionnaires’ disease in Central Harlem has grown to 99 cases, including four deaths.

The last of 12 cooling towers that tested positive for the bacteria currently spawning a Legionnaires’ outbreak in Harlem is being remediated Friday, with officials hoping containment efforts will help prevent another death.