“An outbreak of Legionnaires’ disease has sickened 11 people in Upper Manhattan, 10 of whom have been hospitalized, according to city health officials.
Eight people remained in the hospital on Thursday.
“This disease is very treatable with antibiotics,” Dr. Mary Bassett, the city’s health commissioner, said in a statement. “I encourage anyone with symptoms of Legionnaires’ disease to seek care early.”
The city’s Department of Health said it was “actively investigating” the cases, but had not yet determined the source of the bacteria. A spokesman for Mark Levine, a City Council member who represents the area and who was briefed on the outbreak, said inspectors took water samples from buildings between 145th and 155th Streets. While the city waits for the test results from the 20 cooling-tower systems that were sampled, it has already treated the towers’ water, said Dr. Demetre Daskalakis, the deputy commissioner of disease control.
The cluster of people infected all live in Upper Manhattan and are older than 50, health officials said.
Three of the 11 cases were identified on Thursday, and that number could rise.
“We may continue to see additional cases,” Dr. Bassett said Thursday night at a community meeting at Saint Luke’s African Methodist Episcopal Church on Amsterdam Avenue that was held to discuss the outbreak and answer questions.
Legionnaires’ disease is a serious type of pneumonia commonly caused by breathing in water vapor that contains Legionella bacteria. The disease is most common in the summer because the bacteria thrives in warm water, said Dr. Waleed Javaid, the director of infection prevention and control at Mount Sinai Downtown Network.
Some of the most common culprits in the spread of the disease are cooling towers, humidifiers, hot water tanks and condensers in large air-conditioning units. Whirlpool spas and hot tubs are also sometimes sources of the disease.
In 2015, contaminated cooling towers were the source of a Legionnaires’ outbreak that killed 12 people and sickened more than 120. Legionnaires’ can sometimes contaminate smaller water supplies, as well. In April, three people were diagnosed with Legionnaires’ after the water supply at the Co-Op City complex in the Bronx was contaminated, and one person died.
City health officials said this is the year’s first “cluster” outbreak, in which people across different buildings have fallen ill. Every year, between 200 and 500 people are diagnosed with the disease in the city.
“During a cluster, we’re way, way, way more aggressive than when there’s no evidence of disease transmission from that tower,” Dr. Daskalakis said.
He added that individuals did not need to change their behavior.
“People should drink the water, take showers, bathe as usual, cook as usual, but just be vigilant and persistent and don’t wait,” if flu-like symptoms occur, he said.
“If a person is asymptomatic, they don’t have to worry or panic,” Dr. Javaid said. “Panic is not helpful in this situation if you’re not ill.”
By Thursday, fliers in English and Spanish hung throughout Upper Manhattan. They included a list of frequently asked questions about Legionnaires and a notice to residents: “The risk to most people is low, but if you have flu-like symptoms, please see your medical provider right away.”
Diana Dondrue, 32, said she saw city workers handing out fliers, but she was not overly worried.
Joarty Román, 37, said she was unaware of the outbreak, and was concerned for her elderly parents.
“They should make it more public,” Ms. Román said. “My parents are elderly and I take care of them, so this is something that I should be aware of.”