An outbreak of Legionnaires' disease in New York City's Upper East Side neighborhood has reached 60 cases, but health officials reported a slowdown in new diagnoses on Tuesday. Despite progress in inspecting potential sources, the exact origin of the bacteria remains undetermined.
City Health Commissioner Dr. Alister Martin stated that 49 patients required hospitalization, with 34 having been discharged. Recent data indicates only two new cases were diagnosed from samples taken Thursday through Saturday, a significant decrease from earlier daily counts that reached as high as 11. "All of these things together paint an encouraging sign," Martin said during a virtual briefing.
Legionnaires' disease is a severe form of pneumonia caused by Legionella bacteria, which thrive in warm water systems. Transmission typically occurs through inhaling contaminated water droplets, and the disease does not spread from person to person. While treatable, it can be fatal in approximately 10% of cases, according to the U.S. Centers for Disease Control and Prevention.
Last year, an outbreak in Harlem resulted in seven deaths and over 100 illnesses, with sources later identified as cooling towers at a city-run hospital and the public health lab. In the current Upper East Side outbreak, first identified on July 2, health officials have inspected all 183 cooling towers within the affected ZIP codes. Initial tests, which detect both live and dead bacteria, showed 76 towers tested positive.
Buildings with positive test results include the Guggenheim Museum, several apartment complexes, and private schools. The Guggenheim and 56 other buildings have already completed necessary cleanups, involving draining and disinfecting the cooling towers. The remaining 19 buildings are scheduled to complete their cleanups by Thursday. Health officials noted a change in protocol this year, proceeding with cleanups without waiting for second-round tests, which take about two weeks to confirm live bacteria.