There have now been 90 confirmed cases of Legionnaires' disease in central Harlem, and 15 people are currently hospitalized battling the disease, the city's health department announced.

New York City health officials are continuing to investigate a cluster of Legionnaires’ disease, a serious bacterial lung infection, where the number of cases has risen to 73, including three deaths.

A Legionnaires' disease cluster in the Harlem area of New York City has caused three deaths and over 80 people to be sickened. Here's what it is, symptoms and how it's spread.