Laboratory cultures have confirmed live Legionella bacteria in seven South Bronx cooling towers, the NYC Health Department announced on Sept. 23. It is the first confirmation that bacteria capable of causing illness were growing in towers inside the investigation area. No tower has been identified as the source of anyone's infection.
The department's Legionnaires' disease cluster page, last updated Sept. 24 at 7:10 p.m., counts 23 people with Legionnaires' disease in the Melrose and Morrisania cluster. Three are hospitalized, 15 have been discharged, three did not need hospital care, and two have died. The Sept. 23 announcement cited 22 cases as of Sept. 22, and NY1 reported 23 cases the following day, so the figures reflect different reporting dates rather than conflicting data.
For people who live, work, or shop near the listed buildings, the new list raises an obvious worry about whether they were close to a source. A culture-positive result means live bacteria were present when the water was sampled. It does not show that a tower released the bacteria that made anyone sick.
Seven Addresses Confirmed, Three Results Still Pending
The towers with confirmed live bacteria are at 567 Melrose Ave., 3339 Park Ave., 820 Concourse Village West, 470 E. 161st St., 890 Washington Ave., 1160 Teller Ave., and 1265 Franklin Ave. Culture results are still pending for towers at 234 E. 149th St., 1 E. 161st St., and 1085 Washington Ave. NY1 reported that the pending group includes towers at Yankee Stadium and NYC Health + Hospitals/Lincoln.
Preliminary PCR testing flagged all 10 towers by Sept. 12, and the city ordered the owners to clean and disinfect them by Sept. 14. That means every tower now confirmed by culture had already been treated more than a week before the results arrived. Health Commissioner Dr. Alister F. Martin said each culture-positive tower "was cleaned and disinfected more than a week ago." He said community health workers had spoken with more than 3,200 people, handed out more than 8,800 flyers, and reached out to more than 280 local organizations and businesses.
MedicalDaily previously reported that the cluster had reached 21 cases as outreach widened to ZIP codes 10455 and 10459. At that point, officials knew which towers had Legionella DNA but not which held living bacteria. The new results narrow that question, but the city's guidance for residents has not changed.
PCR Screening Versus Culture Confirmation
PCR testing detects Legionella DNA quickly but cannot tell live bacteria from dead ones, and only live bacteria cause Legionnaires' disease. Culture testing grows samples in a lab for up to two weeks to see whether the bacteria multiply. Because of that delay, the city orders cleaning after any positive screen instead of waiting for confirmation.
The Upper East Side cluster earlier this summer shows why a culture-positive list is not the same as a source. The department tested 183 towers at 160 buildings there and found live bacteria in 59, yet it has not publicly named a single tower as the cause of 94 cases and 11 deaths. Linking a tower to patients generally requires matching bacteria from patient samples to tower samples, and the city has not reported any such match in the Bronx.
Who Should Watch for Symptoms and Seek Care
Risk is highest for people 50 and older, people who smoke or vape, those with chronic heart, lung, kidney, or liver disease or diabetes, and anyone with a weakened immune system. Symptoms include fever, cough, and difficulty breathing, and some people also have chills, muscle aches, headache, fatigue, confusion, or diarrhea. According to the CDC, symptoms usually develop 2 to 14 days after exposure, though it can take longer, so people should tell their provider they are worried about Legionnaires' disease.
The department says, "Legionnaires' disease is deadly but can be effectively treated if diagnosed early." The disease is not contagious, and the city says people cannot get it from drinking water, cooking, or using air conditioning. Residents do not need to turn off their air conditioners.
Anyone who lives in, works in, or recently visited ZIP codes 10451, 10455, 10456, or 10459 and develops flu-like symptoms should contact a provider. Trouble breathing, confusion, or a high fever that is getting worse needs urgent care. People can call 311 or 844-NYC-4NYC (844-692-4692) for help finding a provider.
The department says it will update the tower list daily as the three pending cultures come back. Officials have not said when they will declare the exposure period over or whether any building owner will face enforcement.
Developing Story Timeline
Sept. 24, 7:10 p.m.: The Health Department cluster page reports 23 cases, three hospitalized, and two deaths.
Sept. 23: The department confirms live Legionella in seven cooling towers through culture testing.
Sept. 19 to 20: Outreach expands to ZIP codes 10455 and 10459, and the case count reaches 21 by Sept. 20.
Sept. 12 to 14: PCR screening flags 10 towers, and owners are ordered to clean and disinfect them by Sept. 14.
Sept. 10: The city announces a likely community cluster in Melrose and Morrisania with five cases and one death.
Live bacteria were growing in seven towers; all of them have been cleaned, and 23 people have been diagnosed. The source remains unconfirmed, so for nearby households, watching for symptoms and seeking early care is still the most useful step.
Key Questions Answered
What is new in the South Bronx investigation?
Culture testing confirmed live Legionella in seven of the 10 towers that screened positive. The case count has also risen to 23, including two deaths.
Does a culture-positive tower mean it caused the outbreak?
No. It confirms live bacteria were present when the water was sampled, but it does not link that tower to any patient.
Are the towers still dangerous?
All seven were cleaned and disinfected more than a week before the results came back, according to the Health Department. The three towers with pending results were also ordered cleaned.
Who should see a doctor?
Anyone who lives in, works in, or recently visited ZIP codes 10451, 10455, 10456, or 10459 and develops fever, cough, or trouble breathing. People 50 and older and those with chronic illness should seek care promptly.
Can I get Legionnaires' disease from tap water or air conditioning?
The city says no. The disease usually spreads when people breathe in mist containing the bacteria, and it does not spread from person to person.
Published by Medicaldaily.com
