Chesterfield Legionnaires'

Investigation Overview and Update

Alexander Samuel, MD, MPH, District Health Director

Chesterfield Health District

Lilian Peake, MD, MPH, State Epidemiologist

Virginia Department of Health

October 7, 2019

Legionella bacteria

Common in soil and fresh water

• Approx. 60 species

Uncommon cause of disease in

people

• Most cases caused by Legionella

pneumophila serogroup 1 (Lp1)

Most likely sources of exposure

• Hot tubs

• Decorative fountains

• Cooling towers

• Water used for showering

2

Image source:

www.cdc.gov/legionella/resources/

materials.html

Evolving science of Legionellosis

Legionnaires’ disease - 1976

American Legion convention

Engineered water systems

• Water management plans

2017 - 3 NYC outbreaks

• Cooling towers – linked

environmental and human

isolates

Lack data to quantify relative

risk in homes

Distinct seasonal pattern

2017–2019 studies: Legionella

species and Lp1 detected

through routine sampling

• 2017 CDC convenience study

of U.S. cooling towers

• 2017 U.K. study and 2019

Australia study samples from

household showers

Studies did not correlate

presence of bacteria with

illness

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Legionnaires’ disease Serious type of pneumonia

• Infection caused by breathing in

small droplets of water containing

Legionella

• Most healthy people not affected

• Risk Factors: Age >50, smoking, lung

disease, weakened immune system

• Outbreaks associated with large

or complex water systems

• Leading cause of death from U.S.

waterborne outbreaks

4

Image source:

www.cdc.gov/legionella/resources/

materials.html

Surveillance and investigation of

reportable conditions in Virginia

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Systematic, ongoing

collection, analysis,

interpretation and

dissemination of health

outcome data

Link to public health action

• Investigation

• Control

• Prevention

Investigating Legionellosis cases – Identify outbreaks to reduce ongoing risk

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Legionellosis Case

Travel-Associated

1 case

2 cases within 12 months

>2 cases within 12 months

Healthcare-Associated

1 possible case

1 definite case or ≥2 possible cases within 12 months

More cases within 12 months

Community-Associated

Sporadic case(s) or below baseline

Cases above baseline

Legionellosis U.S., South Atlantic Region and Virginia, 2000-2018

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Legionellosis Cases in Virginia January – September, 2019

Geographic Area # Cases

Outbreak or

Cluster-Related

Cases, #(%)

Age Range

(Years)

Virginia 135 13 (9.6%) 24-97

Central 34 13 (38.2%) 35-87

Eastern 24 0 (0.0%) 34-87

Northern 24 0 (0.0%) 25-97

Northwest 32 0 (0.0%) 35-87

Southwest 21 0 (0.0%) 24-93

Chesterfield County 13 10 (76.9%) 52-81

LEGIONNAIRES’ DISEASE

INVESTIGATION

Chesterfield County

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June activities and findings

May 28

Identified a

possible increase

in cases

June

Additional cases

reported

Public Health Actions Findings

Completed detailed case

investigations

Ruled out

travel-

associated or

health care

facility outbreak

Created line list to

summarize case information

Initial mapping of cases to

identify any geographic

clustering

Public Health Actions Findings

Contacted CDC Legionella experts for

technical assistance

No risk with water

supply identified;

Accuracy of lab

results confirmed

Identified 3

geographic areas

of risk (greatest

overlap of

residences, travel

and locations

visited)

CDC advised

pattern most

consistent with

cooling tower

exposure

Used advanced techniques to map

cases’ residences and travel

Met with Office of Drinking Water to

determine any risks with water supply

Contacted clinical lab to ensure

accuracy of cases’ lab results

CDC led environmental sample

collection (12 sites) • Some field testing was performed

July 2

Notified local health

care partners about

testing and reporting of

cases

July 19

Requested CDC Epi Aid

Alerted clinicians about

increase in respiratory

illness

July 25

Issued press release

about cluster and

geography area at risk

July activities and findings

Test results CDC tested all environmental samples for Legionella

Facility Type Facility Result LP1

Public Greenfield Elementary Legionella + Yes

Midlothian Middle Legionella + Yes

Falling Creek Middle Legionella + Yes

Meadowbrook High Legionella -

Hopkins Road Elementary Legionella +

Private Johnston-Willis Hospital Legionella + Yes

Aleris Legionella -

Kaiser Aluminum Legionella + Yes

Reynolds Legionella + Yes

Marine Corps Services Center Legionella +

Richmond Ice Zone Legionella + Yes

US Defense Supply Legionella + Yes

Results posted on VDH Website

August activities and findings

Public Health Actions Findings

Communicated public health

recommendations (next slide)

Could not

identify

source of the

cluster based

on molecular

testing of

samples from

the patient

and cooling

towers

Launched webpage to provide

testing results

CDC completed whole genome

sequencing (WGS) of Legionella

organisms isolated from patient

and cooling towers

August 8

Press release

about results

of testing

Public Health recommendations

Facilities with positive Legionella results were

asked to:

• Remediate immediately

• Establish or review water management programs

• Sample the towers monthly for a period of 3 months

• Follow CTI and ASHRAE guidelines for cooling towers

• Proper operation of mechanical parts

• Regular cooling tower cleaning

• Ensuring water management programs in place with

Legionella testing

Actions taken by facilities

All sites with positive test results cooperated and

responded to recommendations

Chesterfield County Public Schools (CCPS)

• Immediately closed schools that had cooling towers

that tested positive

• Immediately inspected all CCPS cooling towers

• Included schools beyond the geographic areas at

risk

• Quickly cleaned all CCPS cooling towers

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Current status and next steps

Investigation of Legionaries' disease cluster has concluded

• Last case reported within geographic areas of risk

was on 7/19/19

Close surveillance will continue through rest of CY 2019

• Monitor for new clusters

• Expect increase in sporadic cases due to increased

testing by providers

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In conclusion - What we know

• Cases of Legionnaires’ disease are reported every year

in Virginia

• Chesterfield County observed higher than expected

number of cases, clustered in geographic space and

time

• Several cooling towers, but not all, within the

geographic boundaries of interest tested positive for

Legionella

• Recommendations to mitigate environmental exposures

associated with cooling towers were implemented

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In conclusion - What we don’t know

• There may be unidentified cooling towers in the area

that were not tested

• It is not known whether the Legionnaires’ cases in

Chesterfield County were caused by the presence of

Legionella in these cooling towers

• Some cases may not have been reported due to

misdiagnosis or under-reporting (Occurs in every

investigation)

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QUESTIONS