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Incorporating Novel Methods Into a Standard Environmental Legionnaires’ Disease Investigation and Identifying the Exposure Source of an Outbreak in New York b:;r*,; A total of 17 Legionnaires’ disease cases were identified in an outbreak in a western town in New York. The cases had symptom onset dates ranging from August 1, 2019, to July 1, 2021. Sta from the New York State Department of Health and Chemung County Health Department employed numerous environmental investigation techniques. Environmental health program sta collected 74 environmental samples, including samples from cooling towers, residences, and a wastewater treatment plant. Wind direction was analyzed to determine the potential for the dispersion of aerosolized Legionella . In total, five cases were found to be genetically related by whole genome sequencing. Further testing revealed that isolates recovered from a cooling tower at an industrial facility were genetically related to four of the 2019 cases. Excessive iron was found in the tower and might have suppressed the oxidizing biocide residual and interfered with the evaluation of routine culture and other testing methods. In 2021, clinical and environmental samples from a private hot tub were found to be genetically related to the four matching cases and cooling tower samples recovered in 2019. Keywords: Legionnaires’ disease, Legionella , cooling tower, outbreak, investigation
Matthew Morse, MPH Bureau of Water Supply Protection, New York State Department of Health Braden Savage Bureau of Water Supply Protection, New York State Department of Health Ursula Lauper, MPH, MA Bureau of Water Supply Protection, New York State Department of Health State University of New York (SUNY) Albany School of Public Health David Dziewulski, PhD Bureau of Water Supply Protection, New York State Department of Health State University of New York (SUNY) Albany School of Public Health Gordon & Rosenblatt LLC Lisa Mingle, PhD Wadsworth Center Bacteriology Laboratory Pauline Wanjugi, PhD Bureau of Water Supply Protection, New York State Department of Health State University of New York (SUNY) Albany School of Public Health Seth Blumerman, PhD Division of Environmental Health Sciences, New York State Bureau of Water Supply Protection, New York State Department of Health Danielle Wroblewski, MS Wadsworth Center Bacteriology Laboratory Department of Health Martin Zartarian, MA a broader range of contributing factors are called for. On August 21, 2019, NYSDOH was noti- fied of four urine antigen test-positive (UAT+) patient cases of LD residing within 1 mi of each other in a western town in New York. Following standard NYSDOH protocol, the ensuing investigation was a coordinated eort of a) NYSDOH environmental program sta within the Bureau of Water Supply Pro- tection, b) epidemiological partners from the Bureau of Communicable Disease Control, c) the Wadsworth Center Bacteriology Labora- tory (WC-BL) and Environmental Biology Laboratory (WC-EBL), and d) the Chemung County Health Department (CCHD). The WC-BL was responsible for the analysis and
Introduction Infections from Legionella are a leading cause of waterborne disease outbreaks in the U.S. (Weiss et al., 2017). Legionnaires’ disease (LD) is a type of pneumonia caused by inhaling or aspirating water droplets containing Legionella , a genus of Gram- negative bacteria (Centers for Disease Control and Prevention, 2021). Almost all reported LD patients require hospitaliza- tion and the case fatality rate for LD is 9% (Cooley et al., 2020). After an outbreak of LD in the South Bronx area of New York City in 2015, New York enacted regulations requiring the registra- tion, inspection, maintenance, and annual certification of cooling towers (Weiss et al.,
2017). The Bureau of Water Supply Protec- tion within the New York State Department of Health (NYSDOH, 2023) is charged with enforcing, evaluating, and ensuring compli- ance with state rules and regulations for pro- tection against Legionella . The epidemiological component of an LD investigation seeks to identify associations of cases with locations, whereas the envi- ronmental component focuses on revealing potential sources of exposure. Field inves- tigations of LD outbreaks and clusters often involve sampling a wide array of sources from the built environment. The steady national increase in LD incidence is likely multifactorial; therefore, both novel investi- gative approaches and the consideration of
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Volume 86 • Number 9
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