Outbreak Investigation in the Bioterrorism Setting

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Session VI

• Writing an Outbreak Report

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Session Overview

• Outbreak report function and critical components
• Case studies
• E. coli 0157H7 at the NC State Fair, 2004
• Multistate Outbreak of Monkeypox, 2003

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Learning Objectives

• Understand the role of outbreak investigation
  reports
• Recognize the different types of reports
• Recognize elements to include in outbreak
  investigation reports

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Basic Steps of an Outbreak Investigation

• 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

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Why Communicate the Findings?

• 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

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Why are Outbreak Reports Crucial to Public
Health?

• Example Foodborne outbreak
• Hepatitis A contamination of green onions in TN,
  NC, GA, and PA, Sept-Nov 2003
• Food and Drug Administration (FDA) advisory
  report and MMWR alerted the public and assisted
  with traceback

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Why are Outbreak Reports Crucial to Public
Health?

• Example Respiratory disease outbreak
• Legionnaires Disease (LD) Associated with a
  Whirlpool Spa Display Virginia, Sept-Oct 1996
• Case-patients were likely exposed by walking by
  or spending time near the spa
• The Virginia Department of Health issued
  recommendations for the inspection and
  maintenance of display spas

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Why are Outbreak Reports Crucial to Public
Health?

• Example Respiratory disease outbreak
• Legionnaires Disease (LD) outbreak at a flower
  show in the Netherlands, 1999
• Source whirlpool spa on display
• Lawsuit raised against Dutch government for
  negligence
• Failure to act on available knowledge (MMWR 1996)

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Some Reports are a Part of History

• John Snow

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Some Reports are a Part of History

• Morbidity and Mortality Weekly Report (CDC), June
  5, 1981

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When is the Report Written?

• When the investigation is complete
• When the investigation is ongoing
• Further analysis of data collected in this
  investigation may require revision of these
  findings and recommendations.
• 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.

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Who Writes the Report?

• The field epidemiology / outbreak team
• Visiting EIS officer
• Other authors as assigned
• All participating agencies must agree with
• what is in the report.

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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

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Peer-Reviewed Articles
http//www.ncbi.nlm.nih.gov
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Research Outbreak Updates

• MMWR mailing list
• www.cdc.gov/mmwr/mmwrsubscribe
• FoodNet
• www.cdc.gov/foodnet/
• ProMED-mail listserve
• www.promedmail.org

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Basic Report Structure

• Summary
• Introduction and Background
• Outbreak Description
• Methods and Results
• Discussion
• Lessons Learned
• Recommendations
• Acknowledgements
• Supporting Documentation

2 - 3pages
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Summary

• 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

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Introduction and Background

• Surveillance trends and similar outbreaks
• Include specific events that led to the
  investigation
• 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

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Methods

• Epidemiologic
• Case definition and ascertainment
• Study design
• Microbiological / Toxicological
• Clinical and environmental specimen collection
• Where specimens sent
• Types of analyses performed
• Environmental
• Site visit risk assessment
• Traceback of food products or other items

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Results

• 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

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Results

• Microbiological / Toxicological
• Laboratory findings, e.g. genotyping, DNA
  fingerprinting via PFGE, culture results
• Environmental
• Results of any risk assessments
• Results of any traceback investigation

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Discussion

• Discuss main hypotheses
• Justify conclusions and actions
• Explain action to protect public health

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Discussion

• Highlight any lessons learned
• Problems encountered
• Mistakes made
• Limitations of the study
• Useful lessons for planning future investigations

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Recommendations

• Control Measures
• To control this outbreak
• To prevent future outbreaks
• To improve management of future outbreaks
• Be specific about problems
• Investigation obstacles and shortcomings
• Outbreak causes
• Aim to educate fellow public health professionals
  and inform policy makers

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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

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Case Studies
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Case Study 1
Outbreak of E. coli O157H7 at the North
Carolina State Fair, 2004Epi Notes, December
2004-February 2005http//www.epi.state.nc.us/epi/
pdf/en2004-4.pdf
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Case Study 1

• Condensed version of a more detailed report
• Includes all important components
• Outbreak description
• Methods and results
• Discussion
• Lessons learned
• Recommendations

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Case Study 1

• October 2004 E. coli O157H7 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.

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E. coli O157H7 at the NC State FairEpidemic
Curve
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E. coli O157H7 at the NC State FairResulting
Legislation

• Aedins Law - July 2005
• Permitting process and rules for animal
  exhibitions at state-sanctioned fairs
• Educational campaign about diseases associated
  with contact with animals

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Case Study 2
Multistate Outbreak of Monkeypox Illinois,
Indiana, Kansas, Missouri, Ohio, and Wisconsin,
2003MMWR June 13, 2003http//www.cdc.gov/mm
wr/preview/mmwrhtml/mm5223a1.htm
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Multistate Monkeypox Outbreak Background and
Outbreak Description

• 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

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Multi-state Monkeypox OutbreakMethods

• 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

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Multistate Monkeypox OutbreakLaboratory Results

• CDC tests concluded the virus was monkeypox

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Multistate Monkeypox OutbreakEpidemiologic
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

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Multistate Monkeypox Outbreak Epidemiologic
Results
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Multistate Monkeypox Outbreak Epidemiologic
Results
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Multistate Monkeypox OutbreakResults
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Multistate Monkeypox Outbreak Results

• 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

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Multistate Monkeypox OutbreakTraceback Results

• Common distributor - prairie dogs and Gambian
  giant rats housed together
• Imported animal records - Gambian giant rats
  shipped from Ghana to a wildlife importer in TX
  and sold to the distributor
• The shipment contained 800 small mammals of 9
  different species

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Traceback Investigation
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Multistate Monkeypox OutbreakDiscussion and
Recommendations

• Preliminary findings suggested that the primary
  route of transmission is from close contact with
  infected mammalian pets
• However, the possibility of human-to-human
  transmission cannot be excluded
• Interim guidelines for infection control in the
  community and in health care settings were issued

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Control Measure Guidelines
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Comparison of Case Study Reports

• Both outbreak reports included the major
  elements
• 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

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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.

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References and Resources

• 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 20039515-9.
• 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/ma
  nual/outbreakinvest.pdf
• 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/2
  003/ANS01262.html
• 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 2002837-43.

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References and Resources

• 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
  1991135-43.
• 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.
• Goode B. Outbreak of E. coli 0157H7 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
• Gordis, L. Epidemiology. 2nd ed. Philadelphia WB
  Saunders Company 2000.

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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
  200352(47)1155-1157
• International Committee of Medical Journal
  Editors. Uniform requirements for manuscripts
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  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.

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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/d
  ph/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/en
  trez/query.fcgi
• Reigelman RK. Studying a study and testing a
  test how to read the medical evidence. 4th ed.
  Philadelphia Lippincott Williams Wilkins 2000.

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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/presentati
  ons2003.html
• Update Multistate Outbreak of Monkeypox
  Illinois, Indiana, Kansas, Missouri, Ohio, and
  Wisconson, 2003. MMWR 52(23)537-540
• Zhong L, Goldberg MS, Parent M, Hanley JA.
  Exposure to environmental tobacco smoke and the
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