Transcript Legionellosis In Texas

Legionellosis In Texas
Joseph Ponce
School of Biological Sciences, UT Austin
Mentor: Carol Davis CPH, MSPH
Emerging and Acute Infectious Disease Branch
Texas Department of State Health Services
Introduction
Public Health Significance
• Legionellosis- Serious cases of community
acquired pneumonia
• Etiologic Agent- Legionella pneumophila
serogroup-1
• Obligate intracellular pathogen- replicates within
alveolar macrophages
History
• 1976 American Legion Outbreak
– 221 cases of pneumonia
– 34 deaths
• Unknown etiologic agent
• Aerosol route of infection
• CDC identified L. pneumophila,
as the causative agent
• Source: cooling towers
Bellevue Stratford Hotel Philadelphia, PA
Ecology
• Natural reservoir: aquatic habitats
– Natural water sources
• Rivers, lakes, streams, ponds
– Man-made water sources
• Cooling towers, spas, whirlpools, plumbing
systems
• Found as free living or within protozoa
– Acanthamoeba castellanii, Hartmannella
vermiformis
– Aids in survival in chlorinated water.
Epidemiology
• Transmission
– Inhalation of
aerosols from
contaminated
water sources.
– common
source
exposure
– No person-to person spread
• Risk factors
Environmental
-Poor Water Maintenance
-Poor water
flow/stagnation
-Construction
Personal
-Old Age
-Smoking
-Underlying Disease
-Immune suppression
Risk Factors
Diseases
Legionellosis
Pontiac Fever
-Short Incubation Period
-Self-Limiting
-Non-specific Symptoms
(Influenza-like)
-No Pneumonia
Legionnaires’
Disease
-Incubation period of 2-10
days
-Non-specific symptoms
-Patient Presents with
Pneumonia
-High case-fatality rate in
hospitalized patients
Pathogenesis
Phagocytosis
by alveolar
macrophages in
the lungs.
Entry into
respiratory system
via inhalation.
Aerosolization of L.
pneumophila
Escape of
bactericidal
attack;
prevention of
phagolysosome
fusion.
Intracellular
replication
within
phagosome;
Host cell
death induced
apoptosis
Pathology
Healthy Lung
Lung with Legionnaire’s Disease
Laboratory Diagnosis
• Culture - “Gold Standard”
• Serology
Culture of L. pneumophila on BCYE agar
• Urine Antigen Test
Treatment
• Effective drugs: high cellular penetration and high intracellular
concentration
Quinolones
Example: Fluoroquinolone
Macrolides
Example: Clarithromycin
Rifamycin
Example: Rifampicin
CDC Case Definition
Confirmed case has a compatible clinical history and meets at least one
of the following criteria:
•
1) isolation of Legionella species from lung tissue, respiratory
secretions, pleural fluid, blood or other sterile site
•
2) demonstration of L. pneumophila, serogroup 1, in lung tissue,
respiratory secretions, or pleural fluid by direct fluorescent antibody
testing
•
3) fourfold or greater rise in immunoflourescent antibody titer to L.
pneumophila, serogroup 1, to 128 or greater
•
4) detection of L. pneumophila serogroup 1 antigen in urine
Reporting of Legionellosis
Initial
Reporting
Laboratories and
Medical Providers
report cases to local or
Regional Health
Departments
Local and
Regional
State
National
Texas Department of
State Health Services
Centers for Disease
Control and
Prevention
Local Health
Departments
Regional Health
Departments
Tracking Legionellosis in Texas
• TDSHS
– Emerging and Acute
Infectious Disease Branch
• Surveillance
• Environmental Testing
• Prevention
• December 1999: Legionnaires’
Disease Task Force
• Develop a Legionnaires’ disease
control plan for Texas
Purpose
• To carry out an epidemiological
investigation of Legionellosis in Texas,
2007-2010
– Creation of database
– Variables Analysis
• Patient demographics
• Reporting status of Legionellosis
• Analysis of surveillance data completeness
Methods
Patient Population
• Legionellosis
case report forms
– Patient
Demographics
– Clinical Data
– Lab Data
– Epidemiological
Data
Overview of Methods
Review
Legionellosis
Paper Case
Report Forms
• 2007-2010
Create
Microsoft Excel
Database
• Case Report Forms
Analyze Data
Using Microsoft
Excel
• Pivot Tables and Charts
• Organize data into graphs
• Additional analyses of Existing Data
Assessment of Data Completeness
How
Complete is
the form?
Potential
Exposure
Site Data
Reasons
for Lack of
Exposure
Site
Statistical Analyses
• Percentages
• Incidence Proportions
• Averages
• Medians
Results
Reported Cases of Legionellosis in Texas
by Year, 2007-2010
140
133
Number of Cases
130
120
121
115
110
100
90
81
80
70
N= 415
60
2007
2008
2009
Year
2010
Assessment of Data
Completeness
Completeness of Legionellosis Report Form
• 415 total cases reported to DSHS from 2007
to 2010
– 394 (95%) of the report forms included dates of
symptom onset
– 365 (89%) of the report forms included the second
page of the report form
– 26 (6.3%) of the reports forms were outdated
• Older forms did not have a second page
Potential Exposure Sites for Legionellosis
in Texas, 2007-2010
15%
Reported
PES
44% Hospital
28.6% Long
Term Care
Facility
6.4%
Medical
Office
16% Multiple
Locations
Reported
N=415
Why were the Exposure Site Data
Incomplete?
• 51% of the cases did not list a possible exposure site
• 23% listed the exposure site as “unknown”
• 6.3% reported visiting a possible exposure site
outside of the incubation period
• 5% provided insufficient information
N=415
Demographic Analyses
Percent Cases of Legionellosis by Gender, 20072010
.2%
37.8%
Unknown
Male
Female
62%
N=450
Cases of Legionellosis by Age Group,
2007-2010
70
66
Number of Cases
60
51
50
47
44
46
40
40
36
30
30
21
20
16
17
13
10
10
1
0
0
1
4
3
0
Age Groups
1
3
Percent Cases of Legionellosis by Race/Ethnicity, 20072010
.2% 1%
14.4%
.4%
9%
American Indian or
Alaska Native
Asian
Black or African
American
Other
Unknown
White
75%
N=450
Patient Clinical Data
Percent Cases of Legionellosis Requiring Hospitalization,
2008-2010
1% 2%
Not
Hospitalized
Unknown
Hospitalized
N=318
N=329
97%
Laboratory Data Analysis
Percent Laboratory Testing Methods Used for Diagnosis of
Legionellosis , 2008-2010
0.3%
6.7%
0.3%
1%
Antibody Detection
culture
Direct Fluorescent
Antibody Stain
Unknown
Urine Antigen Test
N=329
91.7%
Other Epidemiological
Analyses
Percent Cases of Legionellosis Reporting Hospital or Longterm Care Facility Visit, 2008-2010
22%
None
Unknown
Yes
17%
61%
N=329
N=329
Cases of Legionellosis with a Hospital or LTC Facility Visit,
2008-2010
40
34
35
Number of Cases
30
25
20
19
20
15
10
5
0
2008
2009
Year
2010
Percent Cases of Legionellosis with Travel History,
2008-2010
17%
None
Unknown
Yes
21%
62%
N=329
Cases of Legionellosis with Travel History by Year,
2008-2010
30
25
Number of Cases
25
20
20
15
11
10
5
0
2008
2009
Year
2010
Legionellosis in Texas by County, 2007-2010
Dallas
Tarrant
Collin
Travis
Bexar
Harris
Top Five Counties with Legionellosis Cases,
2007-2010
County
Population
Number of Cases of
Legionellosis
Dallas
2,435,919
100
Bexar
1,636,642
88
Tarrant
1,825,548
51
Harris
4,096,052
49
Collin
842,364
15
Cases of Legionellosis in the Top Five Counties by
Year, 2007-2010
40
35
Number of Cases
35
35
35
30
Bexar
25
Collin
20
20
17
16
17
15
Dallas
Harris
13
10
Tarrant
5
0
2007
2008
2009
Year
2010
Legionellosis Incidence Rates in Texas, 2007-2010
Incidence Rates of Legionellosis in the Top
Five Counties, 2007-2010
County
Number of Cases
of Legionellosis
Population
Incidence Rate (per
100,00 people)
Karnes
2
16,838
11.8
Clay
1
11,218
8.9
Kerr
4
46,829
8.5
Runnels
1
11,770
8.4
Caldwell
3
38,724
7.7
Comparison of the Number of Cases of Legionellosis
vs. Incidence Rates in Three Texas Counties, 20072010
County
Cases of
Legionellosis
Incidence
Rate (per
100,000
people)
Rank
Rank
According to According to
Total Case
Incidence
Numbers
Bexar
88
5.3
1
15
Dallas
100
4.1
2
9
Tarrant
51
2.7
3
23
Conclusions
Conclusions: Data Completeness
• Positive findings
– 85% of symptom onset data complete
– 89% of reports included the second page of the report form
• Negative findings
– 6.3% of reports were submitted on outdated forms
– Only 15% of forms included possible exposure sites
• Incomplete picture of Legionellosis in Texas
Conclusions: Demographic, Clinical, and
Laboratory Data Analyses
• Profile of Patient with Legionellosis:
– White
– Male
– Older Age: 55-60 years of age
• Almost all patients were hospitalized
• Urine Antigen Test is the most widely used method for
serotype 1
Conclusions: Additional Epidemiological
Analyses
• Legionellosis cases reported more hospital/long-term
care facility visits than travel
• Major Metropolitan areas have the highest numbers of
cases.
• Number of cases does not give a full picture of
Legionellosis in Texas.
• Incidence rates provide insight into other non-major
metropolitan areas in which Legionellosis is significant.
Limitations
• Study only examined three years of data (2007-2010)
• Problems with the case report forms
– Incomplete
– Conflicting information
– Old report forms
Recommendations
• Make changes to the Legionellosis case report forms
– Eliminate data redundancies in Clinical and Epidemiological
information
– Rephrase to explain relevant travel dates
• Dates within incubation period
– Add additional questions to identify possible exposure sites
within the community
• Implement electronic surveillance reporting with
health information exchange
• Design an educational campaign to help protect
those at greater risk
Future Studies
• Demographic trend investigation
– Investigate risk factors associated with typical patient profile
– Occupational Risk Assessment
• High Region/County Incidence Rate
– Bexar county
– Dallas county
– Water treatment investigation
Acknowledgements
TDSHS Infectious Disease Control Unit
Carol Davis
Leslie Brannan
Bobbie Warr
Dr. Gary Heseltine
Wes Hodgson
Acknowledgements
At UT Austin
• Dr. Leanne Field
• Nancy Elder
• Marianna Grenadier
• Dr. Diane Kneeland
A Special Thank You!
Funding generously provided by an
Association of Schools of Public Health/Association of
Public Health Laboratories “Pathways to Public Health
Careers and Internships Grant”
From
The Centers for Disease Control and Prevention