July 2017 Hot Topic: The 2015 New York City Legionaires’ Disease Outbreak: A Case Study on a History-Making Outbreak

Fiery image, Hot TopicThe July-August 2017 issue of the Journal of Public Health Management and Practice (JPHMP) includes “The 2015 New York City Legionaires’ Disease Outbreak: A Case Study on a History-Making Outbreak” authored by Allison Chamberlain, Jonathan Lehnert, and Ruth Berkelman of Emory University School of Public Health. In July of 2015, the Bureau of Communicable Disease of the New York City Department of Health and Mental Hygeine (NYC DOHMH) detected an abnormal number of cases of Legionaires Disease (LD) in the South Bronx. Legionaire’s disease is a pneumonia caused by inhalation of aerosolized water containing L. pneumophila bacteria. This cluster of cases increased to become the largest outbreak of this disease in New York City history. New York City became the first large municipality to implement a regulatory approach to cooling towers to prevent Legionella contamination.

The response to this outbreak began as a standard epidemiological investigation. Case patients and contacts were interviewed in 7 affected zip codes. Eventually 55 cooling towers in the South Bronx were sampled and tested for Legionella. On July 28, 2015, the DOHMH activated its incident command system (ICS) to bring necessary resources to address this threat.

This case is one of 21 that have been developed and will be published in a book in early 2018 by Lippincott, Williams and Wilkins. Each issue of JPHMP in 2017 will feature one of these cases.

The Legionaires’ study is notable in several respects. Although the situation described is an infectious disease outbreak triggering an elegant epidemiological investigation, the case, similar to others in the series, focuses on policy and administrative decisions and actions. New York City DOHMH public health officials allowed the case authors access to themselves and their records to document the history of events, which included controversy and high media attention. Chamberlain and Lehnert travelled to New York City in the summer of 2016, spending several days at the DOHMH including the public health laboratory. Department of Health staff did not want to participate as case authors. They recognized the advantages of outside experts who could do an objective recounting of this public health problem, its resolution, and the pioneering regulations that were put in place.

Indeed, during the cooling tower investigation, disagreements between elected officials resulted in negative media attention. Despite the public disagreements between the mayor and governor, the state and city health departments continued to work closely with each other throughout the outbreak. The lasting impact of the July 2015 LD outbreak included the adoption of Local Law 77, which requires cooling tower registration and certification and also imposes maintenance, inspection, and Legionella testing for New York City towers.


Lloyd F. Novick, MD, MPH is the Founding Editor and Editor-in-Chief of the Journal of Public Health Management and Practice and Professor Emeritus of the Department of Public Health at the Brody School of Medicine, East Carolina University. Follow him on Twitter. [Full Bio]

Recent Case Studies in the Journal of Public Health Management & Practice:*

*Articles may require a subscription to JPHMP or purchase.

Leave a Reply