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. 2. 3. 4. 5. 6. 7. 8. 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? • • • • 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 list www.cdc.gov/mmwr/mmwrsubscribe • FoodNet www.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 ~2-3 pages 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 – – • Microbiological / Toxicological – – – • Case definition and ascertainment Study design 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 – – – • Be specific about problems – – • 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 • 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 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 • • • • 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 • 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 Outbreak Discussion 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. 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