Legionnaire’s Disease Outbreak at a Long Term Care Facility: Environmental Health Considerations

In summer of 2011, Columbus Public Health (CPH) began investigating an outbreak of legionnaire’s disease that was linked to a long-term care facility. This lecture will describe the environmental assessment performed by Columbus Public Health at the facility and the obstacles that were encountered during the investigation.

Legionnella spp. has been typically associated with stagnant water from point sources such as cooling towers, but can also be cultured from potable water systems. As part of the environmental assessment, all water systems in the facility were evaluated for possibility of contamination. The potable water distribution system consisted of two boilers, mixing valves at each boiler, and essentially two distinct and independent loops. The potable water system was assessed for chlorine, pH, and temperature, and sampling was performed at the distill ends, boiler, mixing valve and selected rooms based on exposure by affected individuals. One hundred (100) mL samples were taken based on guidance from the Environmental Legionella Isolation Techniques Evaluation (ELITE) approved lab that was closest in proximity to the site. The Centers for Disease Control (CDC) was contacted for assistance with epidemiologic case studies and a follow up assessment.

Lab samples of the potable water system were shown to culture legionella at several points in the potable water system, thus implicating the water supply as the outbreak vehicle. Remediation efforts that took place included heating of the water system (according to ASHRAE guidelines), soaking of shower heads in bleach solution and follow up testing of the water system.

In closing, the management of legionnaire’s outbreaks in these types of settings are can stretch the resources of local public health and the long-term care facilities and this presentation is designed to educate attendees as to a local health department’s perspective and lessons learned.