92 Confirmed Cases of Legionnaires’ Disease in New York Cluster

Three individuals have died from the infections.

Legionella pneumophila bacteria, which are responsible for causing the pneumonic disease Legionnaires' disease, in a 1978 electron microscope image. Francis Chandler/CDC via AP

A community cluster of Legionnaires’ disease has been identified in the New York City neighborhood of Harlem, with 92 confirmed cases of infection as of Aug. 13, the New York City Health Department said in a statement.

The infections were detected in ZIP codes 10027, 10030, 10035, 10037, and 10039, the city said, adding that “the risk to most people in these ZIP codes is low.”

“If you live or work in the area and have flu-like symptoms, see a health care provider right away. Symptoms include cough, fever, chills, muscle aches, and shortness of breath,” the statement said.

Fifteen people are currently hospitalized, and three individuals have died in this outbreak, the statement added.

Legionnaires’ disease is a type of pneumonia caused by the Legionella pneumophila bacterium, which grows in warm water, the health department said in an earlier update. People get infected when they breathe in water vapor containing the bacteria.

The disease can be caused by plumbing systems where favorable conditions exist for the bacteria to grow, such as evaporative condensers of large air conditioning systems, humidifiers, hot tubs, and cooling towers.

The department identified 11 cooling towers in Central Harlem showing the presence of Legionella.

In its latest statement, the health department said that “any cooling towers with initial positive results for Legionella bacteria have completed the treatment required by the Health Department.”

“We are continuing to monitor and let buildings know if additional treatment is needed,” it said.

The statement clarified that a building’s plumbing system is separate from its cooling tower system.

“This community outbreak is not related to a building’s hot or cold water supply,“ it said. ”Residents in these ZIP codes can continue to drink water, bathe, shower, cook, and use their air conditioner.”

Mayor Eric Adams announced on Aug. 14 that a 12th tower had been identified and that it would undergo remediation by the end of the week.

Only people who inhale the mist are at risk of contracting the disease, which is not contagious.

People who are at increased risk for Legionnaires’ disease include those who smoke, have a chronic lung disease, are aged 50 years or older, take medicines weakening the immune system, or have a weakened immune system. Complications arising from the disease can be fatal, according to the statement.

According to a September 2022 post by the World Health Organization, the Legionella pneumophila bacterium was first identified in 1977, traced to an outbreak of the disease at a convention center in the United States in 1976.

The bacteria are estimated to infect about 10 to 15 people per million annually in the United States, Australia, and Europe.

Out of the reported cases, men account for a majority of cases at 60 percent to 70 percent, with individuals above age 50 making up 75 percent to 80 percent of the total infections.

Tackling the Infection

According to the Centers for Disease Control and Prevention (CDC), symptoms of Legionnaires’ disease typically develop two to 14 days after exposure to the bacteria. In some cases, symptoms may take longer to appear.

In addition to fever, headaches, and muscle aches, people with the infection can also experience confusion, nausea, and diarrhea.

The key to preventing the infection is to control the growth and spread of the bacteria, according to the CDC.

“Buildings and devices at increased risk for Legionella growth and spread should have a water management program based on industry standards,” the agency said.

Owners of cooling towers, hot tubs, decorative fountains, and centrally installed atomizers, misters, humidifiers, and air washers “should follow the manufacturer’s instructions regarding cleaning, disinfecting, and maintenance,” it added.

Other nations have also seen cases of Legionnaires’ disease over the past few months.

On July 8, the Middlesex-London Health Unit declared an outbreak of the infection in London, Canada. At the time, it advised property managers and business owners to “ensure that all cooling equipment is regularly maintained and sanitized as per the manufacturer’s instructions.”

On Aug. 5, the health unit announced the end of the outbreak, identifying 70 Legionella cases in total, out of which 64 were hospitalized and three individuals died.

In June, New South Wales Health in Australia issued an urgent Legionella warning for residents in Sydney after three individuals were diagnosed with the infection in the Sydney suburb of Potts Point.

As of Aug. 11, seven cases have been identified in Potts Point, with the infected in the age range of 45–95 years.