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DIRECT FROM CDC ENVIRONMENTAL HEALTH SERVICES
Tools From the Centers for Disease Control and Prevention Can Help Prevent and Control Legionella Growth and Spread
LCDR Nakia S. Clemmons, MPH, REHS, CIC
drops that can dislodge biofilm contain- ing Legionella ) • Human error (e.g., a person forgetting to change a water filter [Clopper et al., 2021; Garrison et al., 2016]) Legionella Assessment Tools Can Help Support Environmental Health Investigators Environmental health knowledge is criti- cal in preventing and controlling Legionella outbreaks, but many jurisdictions lack envi- ronmental health capacity. The Centers for Disease Control and Prevention (CDC) devel- oped the Legionella Environmental Assess- ment Form (LEAF) to help environmental health practitioners and public health ocials assess and understand facility water systems and aerosolizing devices. LEAF was originally developed as a printable PDF, but in 2022, CDC converted it to an electronic, fillable PDF. These options allow investigators to use LEAF in either digital or print formats. LEAF assists facility water management teams with minimizing the risk of LD by identifying areas at risk for Legionella growth and spread. There are three main sections of LEAF that address facility characteristics, water supply sources, and premise plumb- ing systems. There are also five setting- or device-specific appendices: • Healthcare, Assisted Living, and Senior Living Facilities • Cooling Towers and Evaporative Condens- ers (Photo 2) • Hot Tubs, Whirlpool Spas, and Hydrother- apy Spas • Other Water Devices • Recent or Ongoing Major Construction
Editor’s Note: The National Environmental Health Association strives to provide up-to-date and relevant information on environmental health and to build partnerships in the profession. In pursuit of these goals, we feature this column on environmental health services from the Centers for Disease Control and Prevention (CDC) in every issue of the Journal . In these columns, authors from CDC’s Water, Food, and Environmental Health Services Branch, as well as guest authors, will share tools, resources, and guidance for environmental health practitioners. The conclusions in these columns are those of the author(s) and do not necessarily represent the ocial position of CDC. LCDR Nakia Clemmons is an environmental health ocer in the Water, Food, and Environmental Health Services Branch (WFEHSB) of the National Center for Environmental Health. She manages WFEHSB’s involvement in the Epidemiology and Laboratory Capacity for Prevention and Control of Emerging Infectious Diseases Program.
A ssessing and Controlling Legionella in Complex Water Systems Is an Important Way to Prevent Illness Legionella bacteria are naturally found in freshwater. In the right environment, these bacteria can cause illness when people inhale or aspirate aerosolized droplets of water containing Legionella . Legionnaires’ disease (LD) is a lower respiratory illness characterized by severe pneumonia from these bacteria. This infection often causes hospitalization and is fatal in 1 out of 10 cases (Dooling et al., 2015). The incidence rate of LD is increasing in the U.S. due to a variety of factors, including aging infra- structure and population, increased aware- ness and testing, and urinary antigen test availability (Barskey et al., 2022). Pontiac
fever is a milder illness caused by Legionella bacteria that does not cause pneumonia and usually does not require hospitalization. Legionella bacteria are known to grow in large, complex water systems that are not adequately maintained. Internal and exter- nal factors contribute to Legionella growth in building water systems. Studies show that approximately 90% of LD outbreaks associ- ated with buildings are due to a preventable environmental deficiency, including: • Process failure (e.g., permissive tempera- tures in the favorable range for Legionella growth) • Needed equipment repair (e.g., an auto- matic feeder no longer supplying disinfec- tant in a hot tub; Photo 1) • Unmanaged external change (e.g., nearby construction that results in pressure
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Volume 86 • Number 4
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