Transcript Outbreak Investigation in the Bioterrorism Setting

Session VI
Writing an Outbreak
Report
Session Overview
1. Outbreak report function and critical
components
2. Case studies
– E. coli 0157:H7 at the NC State Fair, 2004
– Multistate Outbreak of Monkeypox, 2003
Learning Objectives
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Understand the role of outbreak
investigation reports
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Recognize the different types of reports
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Recognize elements to include in
outbreak investigation reports
Basic Steps of an
Outbreak Investigation
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Verify the diagnosis and confirm the outbreak
Define a case and conduct case finding
Tabulate and orient data: time, place, person
Take immediate control measures
Formulate and test hypothesis
Plan and execute additional studies
Implement and evaluate control measures
Communicate findings
Why Communicate the Findings?
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Document for action
Share new insights
Record of performance
Substantiate recommendations
In order to…
• Prevent future outbreaks
• Assist in investigation and control of similar
incidents
• Provide a document for potential legal issues
Why are Outbreak Reports
Crucial to Public Health?
Example : Foodborne outbreak
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Hepatitis A contamination of green onions
in TN, NC, GA, and PA, Sept-Nov 2003
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Food and Drug Administration (FDA)
advisory report and MMWR alerted the
public and assisted with traceback
Why are Outbreak Reports
Crucial to Public Health?
Example: Respiratory disease outbreak
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Legionnaire’s Disease (LD) Associated with a
Whirlpool Spa Display – Virginia, Sept-Oct
1996
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Case-patients were likely exposed by walking
by or spending time near the spa
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The Virginia Department of Health issued
recommendations for the inspection and
maintenance of display spas
Why are Outbreak Reports
Crucial to Public Health?
Example: Respiratory disease outbreak
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Legionnaire’s Disease (LD) outbreak at a
flower show in the Netherlands, 1999
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Source: whirlpool spa on display
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Lawsuit raised against Dutch government for
negligence
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Failure to act on available knowledge (MMWR
1996)
Some Reports are a Part of History
John Snow
Some Reports are a Part of History
Morbidity and Mortality Weekly Report (CDC), June 5, 1981
When is the Report Written?
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When the investigation is ‘complete’
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When the investigation is ‘ongoing’
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“Further analysis of data collected in this
investigation may require revision of these findings
and recommendations.”
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“Because of the preliminary nature of this
investigation, future correspondence, MMWR
articles, or other published reports might present
results, interpretations, and recommendations that
are different.”
Who Writes the Report?
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The field epidemiology / outbreak team
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Visiting EIS officer
Other authors as assigned
All participating agencies must agree with
what is in the report.
What are the Types of Reports?
• Complaint form
• Internal report
– Record that outbreak occurred and investigation was
conducted
• State publication
– Newsletter, Website, statewide alert
• MMWR http://www.cdc.gov/mmwr/
• Peer-Reviewed Journals
– Epidemiology and Infection, Emerging Infectious
Diseases, Journal of Hospital Infection
Peer-Reviewed Articles
http://www.ncbi.nlm.nih.gov
Research Outbreak Updates
• MMWR mailing list
www.cdc.gov/mmwr/mmwrsubscribe
• FoodNet
www.cdc.gov/foodnet/
• ProMED-mail listserve
www.promedmail.org
Basic Report Structure
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Summary
Introduction and Background
Outbreak Description
Methods and Results
Discussion
Lessons Learned
Recommendations
Acknowledgements
*Supporting Documentation
~2-3
pages
Summary
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1 - 2 paragraphs
Overview of the investigation
– WHO, WHAT, WHERE, WHEN, WHY/HOW
What caused the outbreak or the causal
hypothesis based on the evidence
Key recommendations
Ongoing actions
Pending / required actions
Introduction and Background
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Surveillance trends and similar outbreaks
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Include specific events that led to the
investigation
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How the outbreak was first reported
Steps taken to confirm the outbreak
Those who became involved in the outbreak
investigation
Description of the area / site / facility
Methods
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Epidemiologic
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Microbiological / Toxicological
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Case definition and ascertainment
Study design
Clinical and environmental specimen collection
Where specimens sent
Types of analyses performed
Environmental
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Site visit & risk assessment
Traceback of food products or other items
Results
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Epidemiological
– No. of questionnaires sent / returned
– No. of cases and descriptive & clinical data
on cases
– Geographic distribution of cases
– Epidemic curve
– Risk factor analysis
– Attack rates by age, sex, exposure
Results
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Microbiological / Toxicological
– Laboratory findings, e.g. genotyping, DNA
fingerprinting via PFGE, culture results
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Environmental
– Results of any risk assessments
– Results of any traceback investigation
Discussion
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Discuss main hypotheses
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Justify conclusions and actions
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Explain action to protect public health
Discussion
• Highlight any lessons learned
– Problems encountered
– Mistakes made
– Limitations of the study
– Useful lessons for planning future
investigations
Recommendations
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Control Measures
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Be specific about problems
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To control this outbreak
To prevent future outbreaks
To improve management of future outbreaks
Investigation obstacles and shortcomings
Outbreak causes
Aim to educate fellow public health
professionals and inform policy makers
Supporting Documentation
Also include the following:
Graphs and tables
Inspection reports
Blank samples of surveys
Letters to management
Menus
Copies of posted notices
Testing results
Press releases
Maps
Case Studies
Case Study 1
Outbreak of E. coli O157:H7
at the North Carolina State Fair, 2004
Epi Notes, December 2004-February 2005
http://www.epi.state.nc.us/epi/pdf/en2004-4.pdf
Case Study 1
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Condensed version of a
more detailed report
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Includes all important
components
– Outbreak description
– Methods and results
– Discussion
– Lessons learned
– Recommendations
Case Study 1
• October 2004: E. coli O157:H7 infection
associated with state fair attendance.
• Case-control study design with 45 confirmed
cases and 188 controls.
• Data analysis and public health laboratory
results (PFGE) revealed petting zoo activities at
the fair as the source of infection.
E. coli O157:H7 at the NC State Fair:
Epidemic Curve
E. coli O157:H7 at the NC State Fair:
Resulting Legislation
• “Aedin’s Law” - July 2005
• Permitting process and rules for animal
exhibitions at state-sanctioned fairs
• Educational campaign about diseases
associated with contact with animals
Case Study 2
Multistate Outbreak of Monkeypox –
Illinois, Indiana, Kansas, Missouri, Ohio, and
Wisconsin, 2003
MMWR June 13, 2003
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5223a1.htm
Multistate Monkeypox Outbreak
Background and Outbreak Description
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CDC received reports of patients with a
febrile rash illness in Illinois, Indiana and
Wisconsin
As of June 10, a total of 53 cases identified
Many reported close contact with pet prairie
dogs and other animals
Laboratory tests indicated the causative
agent was a poxvirus
Multi-state Monkeypox Outbreak
Methods
• MMWR write-up includes combined data from
multiple states
– Methods are not detailed
• Laboratory investigation to identify the virus
• Case-patient interviews to determine exposures,
symptoms, and obtain clinical specimens
• Traceback investigation to identify original
source of illness
Multistate Monkeypox Outbreak
Laboratory Results
• CDC tests concluded
the virus was
monkeypox
Multistate Monkeypox Outbreak
Epidemiologic Results
Demographic information included in report:
• 29 cases (49%) male
• Median age 26 years (range: 4 - 53 years)
• 14 cases (26%) hospitalized
• Earliest onset of illness was May 15
Multistate Monkeypox Outbreak
Epidemiologic Results
Multistate Monkeypox Outbreak
Epidemiologic Results
Multistate Monkeypox Outbreak
Results
Multistate Monkeypox Outbreak
Results
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All patients had contact with animals
51 of 53 cases reported direct or close contact
with prairie dogs
One patient reported contact with a Gambian
giant rat
One patient had contact with a rabbit that
became ill after exposure to an ill prairie dog at
a veterinary clinic
Multistate Monkeypox Outbreak
Traceback Results
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Common distributor - prairie dogs and
Gambian giant rats housed together
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Imported animal records - Gambian giant rats
shipped from Ghana to a wildlife importer in TX
and sold to the distributor
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The shipment contained ~800 small mammals
of 9 different species
Traceback Investigation
Multistate Monkeypox Outbreak
Discussion and Recommendations
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Preliminary findings suggested that the primary
route of transmission is from close contact with
infected mammalian pets
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However, the possibility of human-to-human
transmission cannot be excluded
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Interim guidelines for infection control in the
community and in health care settings were
issued
Control Measure Guidelines
Comparison of Case Study Reports
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Both outbreak reports included the major
elements:
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Introduction and Background
Outbreak Description
Methods and Results
Lessons Learned
Recommendations
Complexity of the report depends on the type
of investigation, the extent of the outbreak, and
the audience of the report
Summary
• Outbreak reports are the final step in
completing your investigation.
• Outbreak reports serve many purposes,
both internally and externally.
• Though outbreak reports may differ in
purpose and audience, reports generally
follow a basic structure.
References and Resources
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Ashford DA, Kaiser RM, Bates ME, Schutt K, Patrawalla A, McShan
A, Tappero JW, Perkins BA, Dannenberg AL. Planning against
biological terrorism: Lessons from Outbreak Investigations. Emerg
Infect Dis 2003;9:515-9.
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Conducting an Outbreak Investigation. The North Carolina
Communicable Disease Control Manual, North Carolina Division of
Public Health. Accessed at
http://www.epi.state.nc.us/epi/gcdc/manual/outbreakinvest.pdf
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Consumers Advised That Recent Hepatitis A Outbreaks Have Been
Associated With Green Onions. FDA Talk Paper. November 15,
2003. Assessed 10/13/2004
http://www.fda.gov/bbs/topics/ANSWERS/2003/ANS01262.html
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Den Boer JW, Yzerman PF, Schellekens J, et al. A large outbreak
of Legionnaires’ disease at a flower show, the Netherlands, 1999.
Emerg Infect Dis 2002;8:37-43.
References and Resources
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Fontham ETH, Correa P, Wu-Williams A, Reynolds P, Greenberg
RS, Buffler PA, et al. Lung cancer in nonsmoking women: a
multicenter case-control study. Cancer Epidemiol Biomarkers Prev
1991;1:35-43.
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Gaudet, M. (2003). Suggestions for Critically Evaluating an
Epidemiologic Study Report. Handout developed for the UNC
Chapel Hill School of Public Health EPID 160 course “Principles of
Epidemiology.”
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Goode B. Outbreak of E. coli 0157:H7 at the North Carolina State
Fair – 2004. EpiNotes, North Carolina Department of Health and
Human Services, Division of Public Health. Accessed at
http://www.epi.state.nc.us/epi/pdf/en2004-4.pdf
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Gordis, L. Epidemiology. 2nd ed. Philadelphia: WB Saunders
Company; 2000.
References and Resources
• Greenberg RS, Daniels SR, Flanders WD, Eley JW, Boring JR.
Medical epidemiology. 3rd ed. New York: McGraw-Hill; 2001.
• Guidelines for EPI-AID Investigations. Division of Applied Public
Health Training, Epidemiology Program Office, CDC.
• Hepatitis A Outbreak Associated with Green Onions at a Restaurant
--- Monaca, Pennsylvania. MMWR 2003;52(47);1155-1157
• International Committee of Medical Journal Editors. Uniform
requirements for manuscripts submitted to biomedical journals:
writing and editing for biomedical publication. Updated November
2003. http://www.icmje.org/ Accessed August 19, 2004.
• Last JM, editor. A dictionary of epidemiology. 4th ed. Oxford
University Press; 2001.
References and Resources
• Levine, S. Redinger, C. and Robert, W. (September / October 2001).
Community Exposure Assessment and Intervention Effectiveness at
Trinity American Corporation, Glenola, North Carolina. American
Industrial Hygiene Association Journal. 62: 649-657.
• Massachusetts Foodborne Illness Investigation and Control
Reference Manual. http://www.state.ma.us/dph/fpprefman.htm
• Millikan B. How to read a scientific article.
http://cbcs.med.unc.edu/howto.htm Accessed July 26, 2004.
• Pneumocystis Pneumonia – Los Angeles. 1981 MMWR 30(21);1-3.
• PubMed database, National Library of Medicine. Available online at
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi
• Reigelman RK. Studying a study and testing a test: how to read the
medical evidence. 4th ed. Philadelphia: Lippincott Williams &
Wilkins; 2000.
References and Resources
• Rothman KJ. Modern epidemiology. Boston: Little, Brown and
Company; 1986.
• Savitz DA. Interpreting epidemiologic evidence: strategies for study
design and analysis. Oxford University Press; 2003.
• The Outbreak Investigation Report, power point presentation by
Arnold Bosman and Meirion Evans. Epiet. Accessed at
www.epiet.org/course/presentations2003.html
• Update: Multistate Outbreak of Monkeypox – Illinois, Indiana,
Kansas, Missouri, Ohio, and Wisconson, 2003. MMWR 52(23);537540
• Zhong L, Goldberg MS, Parent M, Hanley JA. Exposure to
environmental tobacco smoke and the risk of lung cancer: a metaanalysis. Lung Cancer 2000;27:3-18.