MELANIE GRAYCE WEST
Updated January 4th, 2021
New York City health officials are tracking an outbreak of Legionnaires’ disease that has killed two people and sickened dozens of others in the South Bronx, Mayor Bill de Blasio’s administration said Wednesday.
The Department of Health and Mental Hygiene said 31 cases have been reported since July 10.
Most of the cases have been reported from the South Bronx neighborhoods of Highbridge, Morrisania, Hunts Point and Mott Haven, officials said.
“We are conducting a swift investigation to determine the source of the outbreak and prevent future cases,” said Mary Bassett, the health commissioner.
Dr. Bassett said officials are “concerned about this unusual increase” in cases in the South Bronx. She described the outbreak as an “evolving situation in which the numbers may change.”
The department is testing water from water heaters, cooling towers and other sources, such as humidifiers and large air-conditioning systems, to determine the source of the outbreak. The disease is caused by the bacteria Legionella and can’t be transmitted from person to person.
Legionnaires’ disease presents with pneumonia-like symptoms: fever, chills, headache, fatigue and confusion. People with lung diseases, compromised immune systems and smokers, as well as older people, are most at risk.
The disease is common and readily treatable, Dr. Bassett said.
Amar Safdar, an expert in infectious disease and an associate professor at NYU Langone Medical Center, said people can become sick within two days and up to two weeks from exposure.
Large air-conditioning units are a common source of Legionella bacterium and water heaters and or cooling towers “are breeding grounds,” he said.
Pockets of outbreaks typically happen when people come together for a gathering, such as a wedding or luncheon, and the venue is cooled with a centralized air-conditioning unit, Dr. Safdar said.
“If the cooling tower is contaminated, that bacteria can get into the air-conditioning vents and then people inhale the bacteria and come down with infection,” he said.
Nationwide, an estimated 8,000 to 18,000 people with the disease are hospitalized every year, according to the federal Centers for Disease Control and Prevention.
In New York City, 1,449 people were diagnosed with Legionnaires’ disease from January 2002 through December 2011, according to a report published last November by the CDC’s Emerging Infectious Disease journal. Of those, 185 died before health officials finished investigating, according to the report.
Last year, there were 225 cases of the disease in the city, compared with 301 the previous year, according to the city.
The outbreak in the South Bronx follows several others this year.
In January, preliminary test results indicated the cooling towers at Co-Op City, a high-rise complex in the Bronx, were contaminated with Legionella bacterium. Twelve Bronx residents were diagnosed with Legionnaires’ disease; eight were Co-Op City residents.
The cooling tower was decontaminated through physical cleaning and chlorine. Water from the cooling towers was used to chill Co-Op City’s heating and electrical systems, according to the city.
In April and May, 13 people were sickened by Legionnaires’ disease at the Bland House, a New York City Housing Authority building in Queens. Three lived at the Bland House, according to the city. Early tests led investigators to a building senior center, and city officials recommended that no one drink tap water from the senior center.
At a news conference Wednesday, Mr. de Blasio said, “Thank God this is a disease that can be treated, and the important thing is early detection.”
—Josh Dawsey contributed to this article.