A recent outbreak of Legionnaires’ disease in Harlem has now resulted in 70 confirmed cases and three deaths, according to city health officials.

The outbreak has sparked growing concern, especially as the Department of Health reports that two cases were confirmed in the Parkchester section of the Bronx in the past year.

Officials say that 10 buildings within the Parkchester condominium complex are currently being tested for Legionella, the bacteria that causes the disease, after two residents at 1576 Unionport Road tested positive.

Residents say they are alarmed.

“Scary — very scary. I knew it was in Harlem but never here,” said Patricia Murray, of Parkchester.

“I live here. I use the water every day, so it’s like, it can affect me and anyone that is living here,” said Lorraine McMaster, of Parkchester.

To address public concern, Dr. Alexander LaFortune, director of the infectious disease program at Lincoln Hospital, shared how the illness spreads and who is most at risk.

“They get it by inhaling droplets that have been aerosolized from different kinds of things in our environment that use water like cooling towers in buildings that run air conditioners, fountains, other things where water is kind of misting around,” LaFortune said.

Legionnaires’ disease, a type of pneumonia, typically develops two to 10 days after exposure. Symptoms often resemble the flu and can include cough, fever, chills and shortness of breath.

“If a person starts to feel like that and starts to feel really badly, they should get checked out by a doctor, because Legionnaires', if untreated, can be pretty dangerous,” LaFortune said. “If treated with effective antibiotics, it’s something we can definitely deal with.”

LaFortune added that unlike a common cold, symptoms of Legionnaires’ disease tend to worsen over time. Those most at risk include older adults, cigarette smokers and individuals with underlying health conditions such as diabetes, heart disease, kidney disease or HIV/AIDS.

The Health Department is urging those with pre-existing conditions to take precautions, including bathing instead of showering to reduce exposure to mist, filling sinks slowly and continuing regular hand washing. Officials say it is safe to drink cold water from the tap.