Legionnaires’ Disease Outbreak Hits Harlem, Killing One

Legionnaires’ disease, a severe form of pneumonia named after the Legionella bacteria, has struck Manhattan. An outbreak affecting five ZIP codes in Harlem–10027, 10030, 10035, 10037, and 10039–began on July 25, and has infected 22 people as of July 31. One unidentified person has died.

The disease has a mortality rate of 10 percent. However, many healthy people exposed to Legionella do not become sick, making it difficult for city health experts to keep tabs on the true extent of the disease.

“Anyone with flu-like symptoms should contact a healthcare provider as soon as possible,” Deputy Chief Medical Officer Dr. Toni Eyssallenne said in a statement. “Legionnaires’ disease can be effectively treated if diagnosed early, but New Yorkers at higher risk—like adults aged 50 and older, those who smoke or have chronic lung conditions—should be especially mindful of their symptoms and seek care as soon as symptoms begin.”

Legionella bacteria can grow in water systems, usually warm ones. According to the Health Department, these may be: cooling towers, whirlpool spas, humidifiers, hot-water tanks, and evaporative condensers of large air-conditioning systems. People with “recent exposure to hot tubs” may also be at elevated risk of contracting the disease. It is not spread by window-unit air-conditioners, the Health Department says.

Patients contract the disease via infected water vapor; it is not contagious. The “flu-like symptoms” referred to by the Health Department may include chest pain, fever, and a cough. It is treated with antibiotics, with earlier treatment producing better outcomes; the CDC advises that hospitals treat patients with azithromycin or levofloxacin.

The current outbreak reportedly began in local cooling towers, with city officials telling building owners responsible for said towers to “remediate” them within 24 hours.

One outbreak of Legionnaires’ disease struck NYC particularly hard in the summer of 2015. A study published in Emerging Infectious Diseases described it as “one of the largest and deadliest outbreaks of Legionnaires’ disease in the history of the United States,” with “a total of 138 cases and 16 deaths . . . linked to a single cooling tower in the South Bronx.”

That study also provided some important history on the disease: “LD was initially detected in 1976, when an outbreak of illness occurred during a meeting of the American Legion in Philadelphia, Pennsylvania; 221 cases were identified, and 34 infected persons died. The outbreak, which remains the largest community-associated outbreak of LD in the United States, was later linked to the cooling system of the hosting hotel.”

Ronald J. Katter, a NYC-based injury attorney who has represented victims of Legionnaires’, told Straus News that Legionella best thrives in cooling-tower water that is set to sit at around 94 degrees Fahrenheit. In other words, the water that the tower has not yet cooled and circulated.

“If [landlords] treat the water regularly with bleach, or some bactericide, it gets the Legionella levels down to a safe amount,” Katter said. If not, “anybody in the neighborhood just walking by could be exposed to Legionella. You don’t even need to live in that building.”

According to the CDC, outbreaks of Legionnaires’ disease have mostly been on the rise nationwide. “In general, reported cases have been increasing since the early 2000s, with a peak in 2018. While reported cases dropped during the first year of the COVID-19 pandemic, they rebounded in 2021,” the federal public health agency notes.

According to the National Library of Medicine, six “community-associated” Legionnaires’ disease outbreaks have occurred in New York City since 2006, resulting in 213 cases and 18 deaths. They have yet to calculate the effects of the most recent outbreak, given that it is ongoing.

Three outbreaks were linked to cooling towers by molecular comparison of human and environmental Legionella isolates, and the sources for the other three outbreaks were undetermined, according to data from the National Library of Medicine.

The city’s health agency adds that reported incidents are high among Black people, men, and older adults. Incident rates are also generally highest in the Northeast (encompassing New York) and Midwest, especially during summer and fall months.