CDC Reports: Recent Legionnaires' Disease Outbreaks Could Have Been Prevented

As if concerns over Legionnaires’ disease in cities across the country weren’t bad enough, a new report from the Centers for Disease Control and Prevention (CDC) suggests that many of the reported outbreaks involving Legionella bacteria since 2000 could have been prevented with better testing protocols and infrastructure management.

With many cities such as Syracuse, New York; Philadelphia, Pennsylvania; Pittsburgh, Pennsylvania; Detroit, Michigan; and Newark, New Jersey now actively engaged in testing initiatives in response to the outbreak of Legionnaires’ disease in Flint, Michigan, the CDC has developed a toolkit for building owners and managers designed to assist them in the identification of an outbreak in their water systems and in the institution of protocols designed to prevent and/or manage one. The outbreak in Flint has been linked to the city’s water supply system.

“Many of the Legionnaires’ disease outbreaks in the United States over the past 15 years could have been prevented,” CDC Director Tom Frieden, MD, MPH, said in a statement released by the agency. “Better water system management is the best way to reduce illness and save lives, and [our] report promotes tools to make that happen.”

According to the CDC, the incidence of Legionnaires’ outbreaks is increasing. In the past 12 months, some 5,000 Americans have been diagnosed with the disease and more than 20 outbreaks have been reported to the agency. In its report, which was released via the agency’s Vital Signs newsletter on June 7,2016, the CDC analyzed 27 building-associated Legionnaires’ disease outbreaks in the United States, Mexico, and Canada, recording the location, source of exposure, and deficiencies in environmental control of Legionella. The agency found that more effective water management could have prevented most of the Legionnaires’ outbreaks it investigated.

Overall, the problems that contributed to the development of the outbreaks investigated included inadequate disinfectant levels, human error, and equipment breakdowns that led to growth of Legionella bacteria in water systems. Indeed, roughly 65% of the outbreaks occurred as a result of process failures (ie, not having a Legionella water management program), while 52% were due to human error. Approximately 35% were traced to faulty disinfecting equipment, and another 35% were the result of changes in water quality due to external factors such as nearby construction. The most common sources of building-associated Legionnaires’ disease outbreaks were drinkable water (56%), cooling towers (22%), and hot tubs (7%).

In an effort to assist building owners and managers in preventing such failures—and, thus, outbreaks—the CDC also released the resource guide called Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards. The guide includes a checklist to help building executives determine if a water management program is needed, tools to help identify where Legionella could grow and spread in a building, and ways to reduce the risk of Legionella contamination.

“Years of outbreak response have taught us where to find Legionella hot spots,” Nancy Messonnier, MD, director of the CDC’s National Center for Immunization and Respiratory Diseases, said in a statement. “The toolkit will help building owners and managers better understand where those hot spots are and put measures in place to reduce the risk of Legionnaires’ disease.”

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.