chesterfield legionnaires' investigation · lilian peake, md, mph, state epidemiologist...
TRANSCRIPT
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
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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