Legionnaires’ Disease Risks Can Be Reduced By New Water Management Guidelines: CDC

A new report by federal health officials suggests that Legionnaire’s disease outbreaks may be prevented by improving water management systems throughout the United States, to prevent the growth of the bacterium in all forms and uses of public water. 

On June 7, the U.S. Centers for Disease Control and Prevention (CDC) introduced guidelines on how to prevent Legionnaire’s disease outbreaks by improving water management systems through increasing disinfectant levels, removing human error possibilities, and prevention of equipment breakdowns that commonly lead to the growth of Legionella bacteria.

According to the CDC’s Vital Signs report, Legionnaire’s disease is steadily on the rise nationwide, with nearly 5,000 new diagnoses annually. The CDC reports the number of individuals diagnosed with the disease has grown four times the rate from 2000 through 2014 and typically causes at least one fatality out of every ten sickened.

Legionnaire’s disease is a respiratory disease that is caused by breathing in water droplets contaminated with the bacterium Legionella. Legionella is a pathogenic group of Gram-negative bacteria that may cause those sickened to suffer pneumonia or flu-like symptoms and can be fatal to those with weakened immune systems. Most healthy individuals exposed to Legionella do not get the disease. However those over the age of 50 with certain risk factors such as smokers or those with chronic lung disease are more susceptible.

The CDC investigated 27 buildings associated with outbreaks of Legionnaire’s disease across 24 states, U.S. territories, Mexico and Canada from 2000 through 2014 and found approximately 80% of the outbreaks occurred in hotels, long-term care facilities, and hospitals. For each outbreak reviewed, the researchers recorded the type of location, source of exposure, and environmental control deficiencies allowing Legionella to be present.

The study found the most common source of building-associated Legionnaire’s outbreaks stemmed from the facilities’ drinking water that was also used for showering. The researchers held the drinking water accountable for 56% of exposures, followed by 22% of exposures coming from cooling towers, seven percent from hot tubs, and four percent from industrial equipment.

Twenty-three of the investigations indicated a failure was a major contributor to the outbreaks, including failures such as not having a Legionella water management program. Over half of the outbreaks resulted from human error, such as failing to clean or change filters recommended by the manufacturers. Thirty-five percent of outbreaks involved equipment failures such as disinfection systems not working properly.

After analyzing the most prone areas and causes Legionnaire’s disease outbreaks, the CDC released a new outline for building owners and managers to follow called Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards. The program will serve as a guide and check list for building engineers to help identify where Legionella could grow and spread within a building.

Specifically laid out in the guidelines is for engineers to establish a water management program team, describe the building water system using text and flow diagrams, identify area where Legionella could grow and spread, decipher the effectiveness of control measures and how to monitor them, establish ways to intervene when control limits are not met, ensure the program is running as designed and to document and communicate all activities.

Director of CDC’s National Center for Immunization and Respiratory Diseases, Nancy Messonnier, M.D., stated in the press release that the new guidelines will help fight the increase of Legionnaire’s disease and help others identify likely contamination sources.