Southern Nevada Health District
Southern Nevada Health Districtâ€™s Innovative Response to Prevent Outbreaks of Legionaireâ€™s Disease
Clark County is Nevada's largest county located in the southern most portion of the state. The incorporated citiies in Clark County include; Las Vegas, Henderson, North Las Vegas, Boulder City and Mesquite. The county's population of over two million residents additionally hosts over 42 million visitors each year. Tourism is the biggest industry of Clark Couty accounting for nearly $36 billion in spending each year by the county's visitors. The public health agency for Clark County is the Sothern Nevada Health Distirct. The District provides services to both the residents and visitors of Clark County. While the marketing slogan What happens in Vegas, stays in Vegasâ€ may be true for some vistors, outbreaks of illness that occur in Clark County garner nationwide attention. Outbreaks can also cost the implicated facilites litigation costs as victims of the outbreak sue the owners for damages. As a result of the national attention of outbreaks in Clark County, SNHD has developed tools to ensure that outbreaks of disease are limited to the greatest extent possible. One such example is the District's response to reports of Legionellosis. Between 2001 and 2011, SNHD investigated seven outbreaks of legionellosis. Two of the outbreaks in 2011 gained the attention of the national media. As a result of this attention, SNHD developed a program in 2012 to conduct environmental investigations for every reported case of ld. The goal was to prevent outbreaks by determining if a property has an issue with Legionella pneumophila contamination and properly addressing the contamination to prevent an outbreak of legionellosis at the facility. Using experience in investigating these previous outbreaks, SNHD staff developed a procedure to investigate every case of legionellosis reported to it that may have had an exposure at a permitted facilty such as a hotel, or pool, or other area accessible by the public. These investigations were completely voluntary for the facilities' and were not compulsory. The investigations included conducting an environmental assessment of the facility and taking water samples from various sources of exposure. These samples were shipped to an ELITE commercial laboratory to be tested for the presence of Legionella bacteria. Based upon the results of these investigations, SNHD staff would make reccomendations to the facilty to ensure that the presence L. pneumophila if found was corrected. Prior to implementation of this aggressive program, SNHD staff conducted a number of trainings to make the stakeholders in the tourism industry aware of the problem Legionellosis poses to Clark County along with the District's change in investigating these reports and outbreaks. The training was well received and has resulted in the industry's full cooperation in allowing SNHD to conduct these investigations. To date, the District has not been allowed to provide assitance to the industry when it recieves a report of legionellosis. In 2016, the program was slightly modified to improve its sustainablity by decreasing the number of samples, and requiring facilites to cover the cost of testing at the commercial laboratory. Also, since the implementation of the investigation program, there has yet to be an outbreak of legionellosis occurign in Las Vegas. Based on SNHD's previous expierince, there would be an expectation of one or two outbreaks to occur in the the four years that the program has been practiced.
Between 2001 and 2011, Clark County suffered seven reported outbreaks of Legionellosis. Legionellosis is one of the most under reported diseases in the nation. The CDC reports that there are 5,000 cases of legionellosis each year, but the number is under reported due to under utilization of diagnostics tests. Since Clark County's biggest industry is tourism, reports of outbreaks of disease can have a significant impact not only on the implicated facility, but also the larger community. Outbreaks investigated by SNHD gain the attention of the media. The larger or more sensational outbreaks gain national attention.
Each year the over two million residents of Clark County host over forty- two million visitors each year. The average age of these visitors is 48 years old. Most of these visitors stay in one of the 150,000 guests rooms found in Clark County. Most of these rooms are located in buildings that have an increased risk of harboring Legionella pneumophila bacteria and are required by the recently published ASHRAE 188 standard to have water management plans that meet the requirements of the ASHRAE standard to manage the risk of legionellosis in building water systems. This program targets SNHD's 450 permitted hotels and motels. These permitted facilities represent the 150,000 rooms available to Clark County visitors. The program also ensures that the nearly 2,000 permitted public spas or other public potential exposure sources do not cause outbreaks of legionellosis.
SNHD analyzed the outbreaks between 2001 and 2011 and found that prior to each of the seven reported outbreaks, there were single cases of legionellosis in the months prior to the identification of the outbreak. In 2010 after suffering two outbreaks in quick succession, SNHD took the aggressive stance to investigate each reported case of legionellosis that had an exposure at a permitted facility such as a hotel, motel or spa, or other non-permitted public place. Prior to implementation of this program, SNHD waited for multiple cases of legionellosis to occur both in time and location. These outbreaks resulted in an aggressive, compulsory investigation of the facility that included not only water sampling and environmental assessments, but also additional case finding. This additional case finding inevitably led to media attention of the outbreak. Because of the media attention, some of the facilities investigated were reluctant to fully assist in the investigation. The investigation of the outbreaks required many hours of work from employees at both SNHD and the implicated facility so that the outbreak was fully investigated and the large scale remediation of the faculty to eliminate the risk of legionellosis occurred in a timely manner. These investigations cost SNHD tens of thousands of dollars, and the facility even more.
The primary purpose of investigating each case reported to SNHD is to give the facility that may pose a potential source of an opportunity to appropriately respond and correct any deficiencies before an outbreak occurs. If a facility uses this opportunity to address the presence of L. pneumophila within their building water systems, then an outbreak may be prevented and a savings of costs of investigation by SNHD and subsequent litigation costs to the facility are avoided.
The tools used by SNHD investigate single cases are the same tools used to conduct environmental investigations of outbreaks. These include the CDC's Environmental Assessment, CDC's recommended sample site identification along with SNHD's past experience in investigating outbreaks. The innovative approach is to use the single case as an early warning signal and respond by conducting a voluntary environmental investigation to determine if there is an opportunity for L. pneumophila to cause an illness. If L. pneumophila is identified in the facility's water system, then the facility's owner has an opportunity to intervene and remove the threat before additional cases occur. In the four years since implementing the practice, SNHD has yet to identify an outbreak of legionellosis, while in the ten years prior to 2011, SNHD identified seven outbreaks of legionellosis. SNHD has continued to improve the program. In the fall of 2016, SNHD conducted an analysis of the data it collected as a result of the investigations. Nearly 300 samples were taken between January 2012 and May 2015 at investigations associated with public accommodations. The review found that the sampling of cold water from the various faucets located in the room could be removed from the investigation without resulting in a change of the finding of the investigation. Since that time, SNHD has only sampled the hot water outlets at these facilities and made recommendations on remediation based on those results alone.
This practice is innovative in that it attempts to intervene in the colonization L. pneumophila before an outbreak can happen. The practice uses the cooperation of the industry to inform them of the potential to be an exposure source for L. pneumophila, by using environmental investigation principles to identify possible sources for exposure to L. pneumophila. SNHD has also been an early adopter of supporting the industry standard of ASHRAE 188 to establish minimum risk management requirements for building water systems by informing the industry of the status of the proposed standards leading up to adoption in June, 2015.
The goal of this practice was twofold. The first goal was to prevent further outbreaks from occurring in Clark County by conducting an environmental investigation of a single case of legionellosis associated with a permitted facility or exposure to aerosols in a public venue. The working hypothesis was simple; by providing an opportunity to apply an intervention before an outbreak was identified, the outbreak could be prevented from occurring.
The second objective was to provide education opportunities to the regulated community on both the complex nature of Legionella pneumophila colonization of various water systems and the ongoing development of industry standards to manage the risk of legionellosis within a building's water systems.
In 2010, after two outbreaks at local hotels gained the attention of the national media, and recognition that both outbreaks had a sentinel case reported to SNHD in the months leading up to the identification of the outbreak, the SNHD's chief health officer asked that two objectives be set to meet the two goals mentioned above. The first was to develop and implement a formal practice to conduct an environmental investigation into every case of legionellosis that had an associated exposure at a permitted facility or other public location. Staff from SNHD Office of Epidemiology and Environmental Health worked together, using their previous experiences of investigating outbreaks of legionellosis. The teamdrafted a procedure to conduct an environmental investigation into each reported case reported of legionellosis that may have had an exposure to an aerosol during the incubation period at a permitted facility such as a hotel, motel or pool or other public location. Since an outbreak was not being investigated, the facility owners and representatives could refuse to provide SNHD access to conduct the investigation. Participation on the facility's part was voluntary.
The practice was developed modeling the environmental investigation of an outbreak. When SNHD receives a report of a case of legionellosis, and if the case stayed at a permitted public accommodation, used a spa or was exposed to an aerosol of water in a public location, SNHD Environmental Health Staff will commence an investigation within two to three weeks of the report. These investigations are conducted in three phases. The first phase is education of the facility representatives on what legionellosis is, the basic ecology and pathogenesis of Legionalla bacteria, the history of legionellosis both nationwide and in Clark County, and industry's current standard on controlling the risk of legionellosis in the building's water systems. The second phase is the administration of an environmental assessment of the water systems using the CDC Legionella Environmental Assessment form. The final phase is the selection of rooms for the sampling of hot water. Two rooms are selected; the room where the case stayed, and a room on the distal end of the hot water supply line. Each fixture supplied with hot water has two samples taken; one from the first draw of water, and one after one minute of flushing. Various water parameters are measured, and environmental swabs of the inside of the fixtures are taken. An additional sample is taken where the hot water returns to the water heating system. All of these samples are then shipped to an ELITE certified commercial laboratory to be tested for the presence of L. pneumophila. When SNHD receives the result of the sampling, the results are forwarded on to the facility with a recommendation. If the results indicate the presence of L. pneumophila of the same serotype that caused the illness in the case, SNHD recommends that the building be remediated. If the sampling indicates that L. pneumophila is present that is not the serotype of the case, SNHD recommends that the facility contact its water management consultant and determine what next steps are necessary. If no L. pneumophila is found in the sampling, SNHD staff advise the facility that L. pneumophila was not found and that the facility should continue following its water management plan or if they do not have one, to develop one. SNHD requests from the facility that it be notified of how any remediation is to occur and when it will occur. SNHD will spot check the remediation to ensure that it is taking place as described. Once remediation has taken place, SNHD will request follow up sampling be implemented to ensure that L. pneumophila does not recolonize the water system. All costs associated with the time SNHD spends in sampling and testing is billed to the facility.
SNHD also developed a training program. The training provided attendees a basic understanding of the history of legionellosis, ecology of L. pneumophila, how L. pneumophila causes legionellosis, past outbreak investigations and the new practice that SNHD would be implementing in investigating each case of legionellosis reported to it and how it would be funded. The training was focused toward building engineers, risk managers and hotel operators. The ongoing costs of the program include the sending of samples and testing of those samples for L. pneumophila, SNHD staff time to conduct the investigation and to provide adequate follow-up.
During SNHD's complete fiscal year from July 1, 2015 to June 30, 2016, SNHD staff conducted twelve investigations. Each of these investigations took a total of 100 staff hours and required the submission of nearly 250 samples to a private ELITE certified laboratory. Each sample cost $95. SNHD staff spent 50 hours conducting these investigations and appropriate follow-up.
While no formal evaluation has been done on this practice, SNHD has found that no outbreaks were identified after implementation of the practice in 2012. Since its implementation, SNHD has conducted 51 investigations at various locations; 45 were at located at permitted public accommodations, 5 at permitted spas and 1 at a public venue.
This practice has built in sustainability. SNHD staffing costs of the program are provided by the permit fees paid by the regulated community. The costs of the samples are now paid for by the affected facility. A master of public health thesis published in 2014 examined the costs and benefit of this practice. While the costs to the local health department and facility increased after implementation, the prevention of a single outbreak the new practice was worth the extra investment. The thesis found that the total annual cost to both the local health department and resort industry was $1.6 million over the study period of 1.5 years far outweighed the cost of single outbreak which was found to be $700 thousand in investigation and remediation costs and hundreds of millions in litigation costs. SNHD has found that the resort industry is very accepting of the practice. Each facility notified of a case has allowed SNHD to conduct its environmental assessment. Since the implementation of the practice in 2012, there has yet to be an outbreak identified while during the time from 2000 and 2011, there were seven identified outbreaks.