The outbreak of Legionnaires’ disease in Central Harlem has worsened, the New York City Health Department said in an update Tuesday, with three people dead out of 67 diagnosed.There was no information immediately available about the three people who have died.

A Legionnaires’ disease outbreak in Harlem has killed two and sickened 58. Cooling towers tested positive. Health officials urge at-risk residents to watch for symptoms.

Legionnaires' disease is caused by Legionella, a bacteria that can travel through water systems and devices. Although most healthy people don't contract it, it can be deadly for those who do.