The disease is a type of pneumonia caused by the bacteria Legionella, which grow in warm water and can spread in building water systems such as showerheads.

A Legionnaires' disease outbreak in Harlem is blamed for at least three deaths, and NYC officials are warning to watch out for the symptoms.

At least 24 people remained hospitalized nearly two weeks after the cluster of Legionnaires’ disease was first detected in Harlem, with five zip codes affected, city health officials said.