Southern Nevada Health District’s Response to Investigating Legionellosis

Mark 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 casesare 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.

EnvironmentalInvestigation

InvestigationEnvironmental Assessment

INTERVIEW

Building Schematics

Water systems

Water management

plans

Recent sample results

Water System Consultants

HVAC system

Bodies of water and/or water systems

Environmental AssessmentONSITE SURVEY

Tour of water system

All buildings

Collection of chorine residuals

and water temperatures

Guest rooms

Bodies of water

Collection of water and biofilm

samples

Guest Rooms

Bodies of water

Investigation

SAMPLING EQUIPMENTSterile plastic 1 L bottlesSodium ThiosulfateChlorine analyzerThermometerLabelsChain of Custody formDacron-tipped swabsSterile Plastic screw top tubes

SAMPLING-PROCEDUREPre-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:

For example, in the case that had a positive urine antigen test:

the target organism will be L. pneumophila, serogroup 1

ResultsIf 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

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

ResultsEnvironmental 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

Remediation of Legionella is dependent upon where it is found

Additional testing or remediation of the other water systems will be recommended

Remediation

ASHRAE recommends twomethods to remove Legionella:

1: Hot Water Flush(160 - 170˚F)

60˚C (140˚F)90% Kill in 2 Minutes

>70˚C (158˚F)100% Rapid Kill

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

3BiweeklyMonthlyQuarterly

Ongoing control is necessary to ensurethat the facility does not pose an

increased risk to occupants

Active Control Measures

currently in use

Control can include raising the temperature of the water or

adding secondary disinfection

If secondary disinfection is used as acontrol, 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, REHSEnvironmental Health SupervisorSpecial ProgramsDivision of Environmental HealthSouthern Nevada Health District

Phone: (702) 759-0677E-mail: bergtholdt@snhd.mail.org