Investigation of a Legionella Cluster

Somu Chatterjee, MD, MPH.

Regional Epidemiologist,

Wheeling-Ohio County Health Department

Email: somu.k.chatterjee@wv.gov

Ph: 304-234-3682

Cell: 304-830-3710

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Investigation of a Legionella Cluster

Disclaimer:Few slides in this presentation have content similar to, or same as, the report presented by Epidemiology–Aid Team of Center of Disease Control and Prevention, on this particular event.

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Objectives of Presentation

• Epidemiology of Legionellosis

• Field Investigation in Legionella Outbreak/Cluster

• Environmental Assessment

• Importance of Multidisciplinary approach

• Importance of Multi-state Cooperation

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Outline

• Background of Event

• Epidemiology of Legionellosis

• Objectives of Investigation

• Investigation

• Findings

• Summary

• Recommendations

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Additional inputs by OEHS*Additional inputs by OEHS**Office of Environmental Health and Prevention Services

Background

• What happened?– CDC observed a common factor

– State & LHD notified

– Help of OEHS enlisted

• Where did it take place?– Northern Panhandle WV

– Facility “A”

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Background cont…

• Who & When?– CDC

• July 19/2011- case reported with travel to

Facility A

• Aug 24/2011- 2nd case reported with travel to Facility A

• Aug 31/2011- 3rd case reported with travel to Facility A

– LHD reported Legionellosis Death on

• Aug 28/2011

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Background cont…

• Why did it happen?

• How did it happen?

• The Epidemiological Triad– Characteristic of Host

– Characteristic of Agent

– Characteristic of Environment

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Epidemiological Triad

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Source: Snieszko (1974), Blackwell Publishing Ltd. Copyright 1974

Epidemiology - Legionellosis

• Agent: Legionella pneumophila– 80-90% of human infections

– Atypical gram – negative bacillus

– Symbiotic organisms• Algae

• Amoeba

• Ciliated protozoa - invades

• Bacteria

– Habitat : Aquatic bodies

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Epidemiology -Legionellosis

• Causes 2 clinical syndromes:– Legionnaires Disease (pneumonia)

– Pontiac fever (flu like illness)

• Incidence of Legionnaire’s Disease depends on:– Degree of contamination of aquatic reservoir

– Immune status of persons exposed

– Intensity of exposure

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Epidemiology -Legionellosis

• CDC estimates only 3% of sporadic community acquired Legionnaire’s disease in US are correctly diagnosed

• Host risk factors:– Cigarette smoking– Chronic lung disease– Advanced age– Discharge from hospital within 10 days– Immunosuppressive conditions

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Epidemiology -Legionellosis

• Environment:– Natural bodies – small number– Survive for years in refrigerated water– Proliferate in:

• Warm temperatures (250 – 420 C)• Scale• Sediment

• Modes of transmission: – Aerosolisation – Aspiration

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Epidemiology -Legionellosis

13West Virginia Department of Health and Human Resources

Epidemiology -Legionellosis

14West Virginia Department of Health and Human Resources

Epidemiology -Legionellosis

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2008 2009 2010

Hancock 1 0 1

Brooke 1 0 1

Ohio 0 0 0

Marshall 1 0 1

Tyler 1 0 0

West Virginia Department of Health and Human Resources

Objectives of Investigation

1. To conduct case finding to identify possible common exposures among cases

2. To conduct environmental sampling of potential common sources

3. To recommend environmental remediation strategies to prevent additional cases of Legionellosis

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Investigation

• Sept 2/2011– Conference call with local, regional, state (WV,

OH) Public health and CDC. Epi-Aid initiated

• Investigation team:– CDC (Lab, EIS officers)

– LHD, Regional Epi

– OEPS/Infectious Disease Epidemiology

– OEHS/District engineers/District Sanitarians

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Investigation – Case Finding

• Case Definition– Facility Associated

• Signs and symptoms of pneumonia • AND lab confirmed with: culture positive OR urine antigen

positive OR fourfold rise in titers• AND visit to Facility A during incubation period, and onset

of symptoms between June 15 and September 7– Community Associated

• Signs and symptoms of pneumonia• AND lab confirmed with: culture positive OR urine antigen

positive OR fourfold rise in titers• AND present in the WV Northern Panhandle or adjacent

counties during the incubation period, and onset of symptoms between June 15 and September 7

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Investigation – Case finding

• Nationally Notifiable Disease Surveillance System / Travel Associated LD

• Epi-X posting by West Virginia on Aug 25th

• Health advisories in OH and WV• For Laboratory Confirmed cases:

– Contacted hospitals in catchment areas of WV Northern Panhandle/OH adjacent counties to search for LD discharge dx, or lab dx.

• For Non Lab confirmed:– Obtained Resort A staff absences ≥ 4d

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Findings

• Northern Panhandle Legionnaire’s Cluster– 9 cases- (3 Resort Associated , 6 Community

Associated)– Median age = 60 years– 5/9 male– 9/9 hospitalized– 1 died– 5/9 with known travel through Hancock Co.

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Investigation – Distribution of Cases

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1

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CDC Epi-Aid team

Investigation

• Map of the facility

• All cases Interviewed extensively

• DIDE surveillance questionnaire– Patient’s residence (LTCF, Nursing home)

– Travel or stay overnight other than usual residence

– Dental work

– Hospital visit

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Investigation

• Inspected exposures potential in: – Drinking water

– Spa

– Pools

– Hot water tubs

– Race track

– Showers/baths

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Findings - Facility associated cases

• 3 cases visited Facility A (1-2 days)– 3/3 visited the Facility

– Potential sources of exposure near entrance (fountain), parking lot and other places noted.

• 3/3 entered via that particular entrance (5-60min)

• 2/3 report 5-20 min in parking lot, 1/3 reported >20min

– No exposure to other fountains

• No common exposures found.

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Environmental Assessment

• District, State Engineers and Environmental Health professionals– Inspection of water sources in Facility A– Room to Room– All aquatic bodies

• Meteorological considerations– Cooling towers– Data on wind direction, velocity and humidity

from nearest airport

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Map of Cases, Facility A & Cooling Towers in Area

Judith Vallandingham and J.D. Doughlas, OEHS, DHHR, WV, 2011.

Environmental Assessment

• Over to:– Judy Vallandingham,

– Chief, Public Health Sanitation

– Office of Environmental Health Services, WV

• For description of environmental assessment and final recommendations

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ACKNOWLEDGEMENT: CDC - Epidemiology Team - Lab Team

Hancock Co HD - Jackie Huff, Jolene Zuros, Michelle Truax, Carolyne Baker

WV State/ Regional/District - Dee Bixler- Sherif Ibrahim, Jonah Long - Mark Uraco- JD Douglas, Judy Vallandingham, Bob Smith, Brad Hess EIS Officer WV OEPS: Tegwin Taylor Ohio HD Pennsylvania HD

Facility A Staff 

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