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
• Understand the role of outbreak investigation reports
• Recognize the different types of reports
• Recognize elements to include in outbreak investigation reports
Basic Steps of an Outbreak Investigation
1. Verify the diagnosis and confirm the outbreak
2. Define a case and conduct case finding
3. Tabulate and orient data: time, place, person
4. Take immediate control measures
5. Formulate and test hypothesis
6. Plan and execute additional studies
7. Implement and evaluate control measures
8. Communicate findings
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
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
Why are Outbreak Reports Crucial to Public Health?
Example: Respiratory disease outbreak
• Legionnaire’s 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
Why are Outbreak Reports Crucial to Public Health?
Example: Respiratory disease outbreak
• Legionnaire’s 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)
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?
• 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.”
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.
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 listwww.cdc.gov/mmwr/mmwrsubscribe
• FoodNetwww.cdc.gov/foodnet/
• ProMED-mail listserve www.promedmail.org
Basic Report Structure
• Summary• Introduction and Background• Outbreak Description• Methods and Results• Discussion• Lessons Learned• Recommendations• Acknowledgements
*Supporting Documentation
~ 2 - 3pages
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
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
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
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
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
Discussion
• Discuss main hypotheses
• Justify conclusions and actions
• 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• 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
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 2005http://www.epi.state.nc.us/epi/pdf/en2004-4.pdf
Case Study 1
• Condensed version of a more detailed report
• 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
• 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 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
Multistate Monkeypox OutbreakLaboratory Results
• CDC tests concluded the virus was monkeypox
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
Multistate Monkeypox Outbreak Epidemiologic Results
Multistate Monkeypox Outbreak Epidemiologic Results
Multistate Monkeypox OutbreakResults
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
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
Traceback Investigation
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
Control Measure Guidelines
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
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• 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.
• 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
• 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
• 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• 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.
• 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 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
• 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);537-540
• Zhong L, Goldberg MS, Parent M, Hanley JA. Exposure to environmental tobacco smoke and the risk of lung cancer: a meta-analysis. Lung Cancer 2000;27:3-18.