Number of Legionnaires’ disease cases rises to 30; investigation into cooling towers continues

Highbridge, pedestrian bridge
The number of Legionnaires’ cases in the Highbridge outbreak rose to 30 on Friday, but according to the health department, no one has started to get sick since the cooling towers in question were remediated.
Photo Adrian Childress

As the number of reported Legionnaires’ cases in the Highbridge outbreak has risen to 30, the number of cooling towers being investigated has decreased to three.

Among the 30 confirmed cases, 28 patients were hospitalized at some point during the cluster. Four people are currently hospitalized with the disease and two people have died, as of noontime Friday.

All the individuals infected began to see symptoms before the May 23-25 thorough remediation of the cooling towers being investigated as the source of the outbreak, city health department spokesperson Michael Lanza told the Bronx Times. But the number of cases has been rising this week, with two just reported today.

On Thursday, the most recent onset date (when symptoms began) was May 16, but that was pushed to May 20 on Friday — still before remediation.

Beginning May 3, the Highbridge section of the Bronx has seen a cluster outbreak of Legionnaires’ disease, a type of pneumonia that can be spread through water vapor emanating from improperly maintained cooling towers — which can be part of large air conditioning systems — that can be inhaled by outside passersby, regardless of if they live in a building with a cooling tower.

After testing several towers in the area to determine the potential source of the outbreak as cases started popping up, the health department initially found four towers in the Highbridge area with the presence of Legionella pneumophila bacteria. These towers were identified by a rapid screening method that brings results in about 24 hours, allowing the department to act quickly, Lanza said. The department had all four towers disinfected in response.

The rapid method, however, does not differentiate between living or dead bacteria. The bacteria, which causes the disease, is harmless unless it gets a foothold in a warm damp environment, city health officials said.

To narrow down the potential source among the initial four towers, samples were tested by culture to determine if the bacteria could be grown from them, a two-week process that can be definitive for identifying the presence of live Legionella pneumophila bacteria in the cooling tower, Lanza said.

This process found that just three of the four towers were positive,  and the three towers underwent additional remediation, cleaning and disinfection, Lanza said. The three towers are the subject of further investigation to see if the department can connect a culture to patient specimens to target which of the three towers spread the illness.

The health department would not provide the specific location of the cooling towers at this time, and the department’s investigation is ongoing; Highbridge is still considered an investigative zone.

Legionnaires’ disease typically has a two-week incubation period from when the bacteria enters the body to when the individual gets sick, and the department monitors the number of cases for two incubation periods from the last onset date — now May 20 — he said.

While the risk is believed to be lower now, people who have been in the Highbridge area over the past month who have flu-like symptoms, fever, cough or difficulty breathing should seek immediate medical attention from urgent care or a primary care provider, according to the health department.

People ages 50 and older, cigarette smokers and people with chronic lung disease or compromised immune systems are at higher risk, for whom the disease can be severe or even fatal, according to the health department.

The disease is not contagious, and when caught early, it can be treated with antibiotics, according to health officials.

The attorney general’s office recently came to an agreement with Verizon following an investigation that alleged the company violated cooling tower laws from 2017-2019 in the Bronx and across the state. The laws were created to prevent the spread of Legionnaires’ disease following a 2015 outbreak in the Bronx.

Reach Aliya Schneider at [email protected] or (718) 260-4597. For more coverage, follow us on Twitter, Facebook and Instagram @bronxtimes

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