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Southern Nevada Health District’s Response to Investigating LegionellosisMark Bergtholdt, MPH, REHS
Why is Las Vegas Different • Clark County has a population of 2 million • 40 million visitors each year • 150,000 hotel rooms • 91% weekend occupancy
More than 20% of cases are associated with travel
Press Coverage • Legionnaires' disease infects 6 at Las Vegas hotel; Aria hotel finds legionella bacteria in rooms (NY Daily News, July 15, 2011) • Las Vegas: Health district says Luxor guest died of Legionnaires‘ (Los Angeles Times, January 31, 2012)
Investigation Trigger • SNHD receives a report from the CDC or local health care provider that an individual contracted Legionellosis with a possible exposure from either a hotel room or exposed to a potential aerosolized source of Legionella • The report includes how the Legionellosis was diagnosed and the exposures. • The Legionella bacteria species and serotype diagnosed are considered the target organism.
Investigation Trigger • As soon as SNHD has enough information such as: • Dates of stay • Names of cases • Room numbers • Contact is made with the facility and an investigation is scheduled within 24 hours.
SAMPLING EQUIPMENT • Sterile plastic 1 L bottles • Sodium Thiosulfate • Chlorine analyzer • Thermometer • Labels • Chain of Custody form • Dacron-tipped swabs • Sterile Plastic screw top tubes
SAMPLING-PROCEDURE • Pre-Flush sampling the Hot and Cold water • Post-1 minute flush sampling the Hot and Cold water • Swab samples of faucets / emitters
Types of rooms tested • Case room • Hot water return • One additional room furthest from the hot water source • Only rooms on the hot water system where the case stayed • Other possible sources
SNHD Sends results to ELITE Certified laboratory (Environmental Legionella Isolation Techniques Evaluation)
SNHD Sends results to ELITE Certified laboratory (Environmental Legionella Isolation Techniques Evaluation) • Results of the testing is shared with the facility
Action will be taken if the results have identified the organism that caused the illness
For example, in the case that had a positive urine antigen test: the target organism will be L. pneumophila, serogroup 1
If the target organism is identified in the results of room fixtures or hot water system, SNHD will require that the water system supplying the room water system be remediated based on the following results: • Target organism in bulk water greater than 10 cfu/ml • Environmental swabs from two different fixtures greater than 10 cfu/ml • Water or environmental swabs from two different fixtures less than 10 cfu/ml Results
Results • If a single water sample or environmental swab returns with results less than 10 cfu/ml, but is the target organism, then the SNHD shall determine what type of remediation is required
Results If the results find other Legionella in the samples, SNHD will make a recommendation based on results
Environmental samples collected from areas that are not guest room fixtures must meet the OSHA guidelines • If the samples do not meet OSHA guidelines, then remediation of the system will be recommended Results
Remediation of Legionella is dependent upon where it is found Additional testing or remediation of the other water systems will be recommended
ASHRAE recommends two methods to remove Legionella:
1: Hot Water Flush (160 - 170˚F)
>70˚C (158˚F) 100% Rapid Kill 60˚C (140˚F) 90% Kill in 2 Minutes
2: System chlorination (min 2 ppm, 2 hours)
Follow-up testing of the water system is performed to ensure the remediation was effective
After remediation, the facility must adhere to a strict monitoring sample schedule
3 Biweekly Monthly Quarterly
Ongoing control is necessary to ensure that the facility does not pose an increased risk to occupants
Control can include raising the temperature of the water or adding secondary disinfection
If secondary disinfection is used as a control, the facility may need to obtain public water system (PWS) permit
Rationale Behind Investigating a Single Case • Between 2000 and 2012 SNHD investigated seven outbreaks related to large hotels. • The data indicated there was one sporadic case, shortly followed by several other cases. • Being proactive by looking at one reported case as a canary in a mine can prevent other cases from occurring later. • Since implementation of investigating single cases there have been no other outbreaks identified by SNHD
SNHD is proactive by responding to and investigating each case + Facility acting proactively by using the best practices and taking the appropriate corrective action = No further action if SNHD receives report of a case associated with the facility prior to the remediation.
If SNHD investigation does not identify the target organism, then the investigation is closed and potential outbreak can be ruled out • Minimizes the need for public notification/media attention
Cost/Benefit Analysis • Prior to conducting investigations of single cases, SNHD spent an estimated $5,611 annually investigating to outbreaks. • Now SNHD spends $82,675 per year. • Costs to the facility has a wide range: • a low of $16,000 • a high of $1,000,000
Cost/Benefit Analysis • Costs of an outbreak • Hospitalization costs range • Low of $13,000 • High of $71,000 • Cost to SNHD of one outbreak in Las Vegas was $21,000 • Liability costs • In 2011, eight guests sought $337,500,000 in damages • Reputation costs • Internet has sped the speed of information
Cost/Benefit Analysis • Summary • Responding to every case may cost SNHD ten times more over a year • Mechanisms are in place to have the costs covered by the resort industry • While costing the resort industry $150,000 per investigation outweighs the costs of hundreds of millions in litigation along with reputation damage.
Reports on the recent investigations can be found at • www.snhd.info • Click ‘Health Topics’ • Then click ‘Statistics, Surveillance and Reports’ • QR Code and website on Handout
SNHD procedures on investigating single cases of Legionellosis can be found at: • http://www.southernnevadahealthdistrict.org/lrl/
Thanks • SNHD Office of Epidemiology • SNHD Environmental Health • Special Programs Office • Safe Drinking Water Program • Public Accommodations Office • Bureau of Safe Drinking Water, Nevada Division of Environmental Protection • UNLV, School of the Community Health Sciences
Contact Information Mark Bergtholdt, MPH, REHS Environmental Health Supervisor Special Programs Division of Environmental Health Southern Nevada Health District Phone: (702) 759-0677 E-mail: email@example.com