A Legionnaires' disease outbreak in New York's Central Harlem neighborhood has now sickened 90 people and caused three deaths, health officials said Tuesday.

A Legionnaires' disease cluster in the Harlem area of New York City has caused three deaths and 90 people to be sickened. Here's what it is, symptoms and how it's spread.

Adults who have been in the affected area since late July with flu-like symptoms, fever, cough or difficulty breathing should seek immediate medical attention, health officials say.