What Riverdale residents should know about the South Bronx Legionnaires’ disease outbreak

A second person died in connection with the Legionnaires’ disease outbreak in the South Bronx, as announced by the city Sept. 17. The outbreak has sparked discussion throughout the borough, and while there is currently little threat to the northwest Bronx, it is important for residents to understand the disease.

There is currently no indication that there is a community cluster in Bronx Community District 8 — which includes Riverdale, Spuyten Duyvil, Kingsbridge, Marble Hill, Van Cortlandt Village and part of Kingsbridge Heights — a spokesperson from the city’s department of health and mental hygiene told The Press. There are also no open building investigations, according to the spokesperson.

Legionnaires’ disease is a type of pneumonia, or lung infection, caused by Legionella bacteria that grow in warm water, according to the health department. It is important to note that it is not contagious between individuals. It is also not spread by drinking water, cooking or using air conditioning.

As of Sept. 28 at 4:45 p.m., 23 people tested positive for Legionnaires’ disease in the South Bronx, the health department said. Sixteen have been discharged from the hospital, two were still hospitalized, three were not hospitalized and two had died, according to the health department.

The Upper East Side outbreak earlier this year led to 82 cases and five deaths, according to a July 21 report from the department, bringing the 2026 total to 105 cases and seven deaths.

People who breathe in mist that contains the bacteria can get sick, but most people exposed to the bacteria do not develop Legionnaires’, the health department said. Illness usually occurs after high or repeated exposure.

Common sources of exposure are cooling towers, hot tubs and spray fountains, according to the health department.

The illness causes flu-like symptoms such as fever, chills, muscle aches and cough, according to the health department. Some may also experience headaches, fatigue, loss of appetite, confusion or diarrhea, the department said.

People who are at an increased risk include people aged 50 and older, smokers or vapers, those with diabetes or chronic heart, lung, kidney or liver disease, and those with medical conditions that weaken their immune systems, the department said. 

The health department also said there is no vaccine or medicine to prevent Legionnaires’, but it can be treated with antibiotics. Maintaining water systems where Legionella might grow is the best way to prevent the disease, according to the department.

A week before the second South Bronx death, the health department announced it was launching an investigation into a likely community cluster of Legionnaires’ disease in parts of Melrose and Morrisania, citing 10 cooling towers in the area that were found to have traces of living or dead Legionella bacteria, including at Yankee Stadium.

The state department of health’s Cooling Tower Registry Weekly Extract Map — which provides the location, Legionella sampling results and operational status of cooling towers — previously showed five sites with cooling towers in the northwest Bronx. However,  the department said some city cooling towers were erroneously included in the database and were being removed. The New York City portion of the map remained largely blank by press time, and the department did not respond to clarify how many towers were in the area by press time. 

The Press confirmed several cooling tower sites in the area, including The Conservative Synagogue Adath Israel of Riverdale, Lehman College and apartment building River Terrace.

Zef Redzaj, a handyman at River Terrace, explained that sites are required to test monthly, and that third-party chemical companies come in to take a sample. River Terrace was last tested Sept. 8, he said.

Lehman College’s communication team said the school’s tower is in full compliance with rules and regulations for maintenance, testing and cleaning.

A spokesperson for the city’s department of health and mental hygiene told The Press aside from the monthly testing, the department does unannounced, routine inspections for cooling tower systems citywide.

Legionella bacteria is naturally occurring in our environment, the spokesperson said, and grows in stagnant, warm water. The city sees between 200 to 600 cases of Legionnaires’ each year.

Last year, a Central Harlem cluster led to 114 cases and seven deaths, according to an Aug. 9, 2025 release from the department. The year before that, there were 258 cases, according to department data.

“At the health department, we do everything we can to prevent Legionnaires’ disease clusters from happening in the first place — and to respond urgently when they do,” the spokesperson said in a statement to The Press.

Dr. Gregory Weston, an associate hospital epidemiologist at Montefiore Medical Center, told The Press that since the symptoms for Legionnaires’ disease are similar to a lot of other diseases, it can be difficult to pinpoint if an illness is Legionnaires’.

Any person with symptoms that are affecting their daily living — shortness of breath, chest pain, weakness, diarrhea — or who is simply concerned, should seek care, Weston said. This could mean calling their physician for advice, or visiting urgent care if symptoms are severe.

Considering how many people live on a city block, Weston said, the number of those who are a part of the South Bronx outbreak is relatively small. Still, awareness is crucial.

“It’s not that there’s a huge risk for everybody, but there is a risk that is important to know about,” Weston said. “If they start to feel sick, it’s important to see a doctor.”