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I is for Investigation

I is for Investigation. Outbreak Investigation Methods from Mystery to Mastery. Session VI. Writing an Outbreak Report. Session Overview. Outbreak report function and structure Case studies Mycobacterium skin infection outbreak in New York in 2012 Multistate outbreak of listeriosis in 2011.

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I is for Investigation

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  1. I is for Investigation Outbreak Investigation Methods from Mystery to Mastery

  2. Session VI Writing an Outbreak Report

  3. Session Overview • Outbreak report function and structure • Case studies • Mycobacterium skin infection outbreak in New York in 2012 • Multistate outbreak of listeriosis in 2011

  4. Learning Objectives • Explain the role of outbreak investigation reports • Describe different types of outbreak reports • List elements to include in outbreak investigation reports

  5. 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 studies • Implement and evaluate control measures • Communicate findings

  6. Outbreak Report Function and Structure

  7. Why Communicate the Findings? • Serves as a document for action • Gives insight about pathogen or transmission mechanism • Documents the magnitude of health problems and justifies activities • Serves as a performance measure for Public Health Preparedness capabilities • Is a basis for research or evaluation

  8. Communicating Findings • Prevent future outbreaks • Assist in investigation and control of similar incidents • Provide a document for potential legal issues

  9. Why are Outbreak Reports Crucial to Public Health? Example: Foodborne outbreak Invasive listeriosis in Louisiana, Jan-June 2010 • First outbreak to implicate hog head cheese • Voluntary recall by producer • Publication served to • Inform public health practitioners about new transmission vehicle • Emphasize food safety requirements • Alert high risk populations

  10. Why are Outbreak Reports Crucial to Public Health? Example: Respiratory disease outbreak • 1996 Legionnaire’s Disease (LD) outbreak associated with a whirlpool spa display • Exposure from walking by or being near spa • 1999 LD outbreak at a flower show in the Netherlands • Source: whirlpool spas on display • Lawsuit raised against Dutch government • Failure to act on available knowledge (1996 MMWR)

  11. Some Reports are a Part of History John Snow Image Source: www.circleofblue.org 

  12. Some Reports are a Part of History Morbidity and Mortality Weekly Report (CDC), June 5, 1981

  13. When is the Report Written? • When the investigation is ‘complete’ • When the investigation is ‘ongoing’ • Preliminary results impact public health / medical practice • High profile or high interest • Long investigation • Often include disclaimer

  14. Who Writes the Report? • The outbreak / field epidemiology team • Visiting EIS officer • Epidemiologist, environmental health, laboratorians, clinicians • Participating state or federal agencies All participating agencies must approve the report.

  15. Types of Reports • Complaint form • Internal report • Record that outbreak occurred and investigation was conducted • State publications • Newsletter, bulletin, website, press release or alert • National bulletin • MMWR http://www.cdc.gov/mmwr/ • Peer-Reviewed Journals • Epidemiology and Infection, Emerging Infectious Diseases, Journal of Hospital Infection

  16. Peer-Reviewed Articles http://www.ncbi.nlm.nih.gov/pubmed

  17. Research Outbreak Updates • MMWR: http://www.cdc.gov/mmwr/ • FoodNet: www.cdc.gov/foodnet/ • Bulletin of the World Health Organization www.who.int/bulletin/ • ProMED-mail listserv www.promedmail.org

  18. Basic Report Structure • Context / background • Initiation of investigation • Investigation methods • Findings / results • Discussions and/or conclusions • Recommendations • Acknowledgements +Supporting Documentation

  19. Length of Report • Bulletin article • 1-2 pages (500-1000 words) • Internal report • 2-3 pages • Peer-reviewed manuscript • 4-8 pages

  20. Context and Background • Description of the problem • Suspected or known etiology • Signs, symptoms, diagnoses • Time of occurrence • Population affected • Location / and geographical areas involved

  21. Initiation of Investigation • How notification was received • Date and time notification was received by the agency • Date and time investigation was initiated

  22. Methods • Initial activity / verification • Laboratory results, case finding efforts • Data collection and analysis methods • Case definition and case identification • Epidemiologic study design • Environmental or clinical sample collection • Review of reports • Exposure assessment and classification • Tools used • Questionnaires, epidemic curves, attack rates

  23. Epidemiological Results • Questionnaire / interview response rate • Cases • Number • Descriptive and clinical data • Geographic distribution of cases • Epidemic curve • Attack rates by age, sex, exposure • Risk factor analysis, including ORs / RRs if applicable

  24. Laboratory, Clinical, and Environmental Results • Laboratory results • Findings from clinical or environmental testing • Genotyping, DNA fingerprinting, culture results • Environmental • Results of any risk assessments • Results of any traceback investigation

  25. Discussion and/or Conclusions • Discuss main hypotheses and public health impact of findings • Note problems or limitations that could impact results • Present conclusions about the cause of the outbreak

  26. Recommendations • Uses • To control or mitigate this outbreak • To prevent future outbreaks • To improve management of future outbreaks • Basis • Investigation obstacles and shortcomings • Outbreak causes

  27. Acknowledgements • Key investigators • Report authors • Both names and titles

  28. 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

  29. Case Studies

  30. Case Study 1 Outbreak of Mycobacterium chelonae Infection Associated with Tattoo InkKennedy, Bedard, Younge, et al. N Engl J Med 2012; 367:1020-1024. September 13, 2012.

  31. Tattoo Ink OutbreakContext and Background • Pathogen • Not a common cause of skin infections • Setting • Previous case reports and outbreaks • General description of current outbreak Initiation of Investigation • Dermatologist reported case to health department Stain showing Acid-Fast Bacilli Kennedy et al. NEJM 2012; 367:1020-1024

  32. Tattoo Ink OutbreakEpidemiologic Methods • Interviews and site visit • Index patient • Tattoo artist and studio • Additional case finding • Laboratories and tattoo parlors • Assessment and treatment

  33. Tattoo Ink OutbreakLaboratory Methods • Laboratories used • Samples tested • Tests performed Typical Rash Associated with Mycobacterium chelonae Infection Kennedy et al. NEJM 2012; 367:1020-1024

  34. Tattoo Ink OutbreakEpidemiologic Results • Ink purchased in April, additional supply ordered later • 19 cases (15 confirmed, 4 probable, 1 suspected) • 13 men, 6 women • Age range 18 – 48 years • Attack rate among parlor patrons • 0% May-August 2011 • 65% in November 2011

  35. Tattoo Ink OutbreakLaboratory Results • Biopsy from 17 of 19 case patients • Microscopic evidence in all samples • M. chelonae isolated from 14 of 17 samples • CDC confirmed same M. chelonae genetic pattern in 11 clinical samples and 1 unopened bottle of ink • No M. chelonae found in environmental samples from tattoo parlor

  36. Tattoo Ink OutbreakDiscussion and Conclusions • Conclusion: Ink, not tattoo parlor, was source of infection • Discussion • Brief review of mycobacterial contamination during tattoo procedures • Limitations • Implication of possible under-reporting of cutaneous mycobacterium infections

  37. Tattoo Ink OutbreakRecommendations • Educate tattoo artists and patrons • State laws related to tattooing • Best practices • Risks • Signs of a reaction and steps to take • CDC issued nationwide alert • Manufacturer issued voluntary recall • Enhanced oversight needed for tattoo parlors and ink manufacturing

  38. Case Study 2 Multistate Outbreak of Listeriosis Associated with Jensen Farms Cantaloupe --- United States, August--September 2011 MMWR October 7, 2011 / 60(39);1357-1358 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6039a5.htm?s_cid=mm6039a5_w

  39. Multistate Listeriosis Outbreak Context and Background • 5 sentences • Pathogen • Transmission • Clinical signs and symptoms • Public health concern • Treatment Listeria electron micrograph. Photo: CDC/ Dr. Balasubr Swaminathan; Peggy Hayes, 2002

  40. Multi-state Listeriosis OutbreakInitiation of Investigation • 3 sentences • September 2, 2011 • Colorado Dept. of Public Health and Environment reported 7 cases of listeriosis to CDC since Aug 28 • Normal = 2 cases in August • Patient interviews using Listeria Initiative questionnaires • All 7 reported eating cantaloupe • 3 reported eating Rocky Ford cantaloupe

  41. Multi-state Listeriosis OutbreakInvestigation Methods • 2 sentences • Case definition • Criteria for identifying outbreak strain of L. monocytogenes • 3 possible PFGE patterns • Criteria for comparison group

  42. Multistate Listeriosis OutbreakEpidemiologic Results • Outcome information • 19 initial cases identified • OR for cantaloupe 14.9 (95% CI 2.4, ∞) • Cantaloupe traceback • Jenson Farms, Colorado

  43. Multistate Listeriosis OutbreakResults • PulseNet identified an additional, multi-state cluster with a 4th PFGE pattern associated with cantaloupe consumption • By September 29, 2011 • 83 cases in 19 states, including 15 deaths • 88% aged > 60 years • 55% female • 2 pregnant • 92% of those reporting food consumption ate cantaloupe

  44. Multistate Listeriosis OutbreakEpidemic Curve Number of infections with outbreak-associated strains of Listeria monocytogenes (n = 83), by date of illness onset* --- United States, July--September 2011

  45. Multistate Listeriosis OutbreakDiscussion and Conclusions • Conclusion • Jensen Farms cantaloupe implicated • Voluntary recall issued • Discussion on “unusual features” • First melon-associated listeriosis outbreak • Large outbreak associated with 4 PFGE patterns • Large number of deaths

  46. Multistate Listeriosis OutbreakRecommendations • Do not eat cantaloupes from Jensen Farms Especially higher risk groups: • Older adults • Persons with weakened immune systems • Pregnant women • Discard cantaloupe of uncertain origin • Additional listeriosis advice available

  47. Comparison of Case Study Reports • Both outbreak reports included the major elements • Complexity and venue of the report varies • Type of investigation • Urgency of the message • Extent of the outbreak • Audience

  48. Summary • Outbreak investigations are not complete without documentation in a written report • Outbreak reports serve many purposes, both internally and externally • Outbreak reports may differ in purpose and audience, but follow a foundational structure

  49. 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. • Centers for Disease Control and Prevention. Outbreak of Invasive Listeriosis Associated with the Consumption of Hog Head Cheese – Louisiana, 2010. MMWR 2011;60(13):401-405. Available from: http://www.cdc.gov/mmwr/pdf/wk/mm6013.pdf • Centers for Disease Control and Prevention. Hepatitis A Outbreak Associated with Green Onions at a Restaurant --- Monaca, Pennsylvania. MMWR 2003;52(47):1155-1157. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5247a5.htm. • Centers for Disease Control and Prevention. Multistate Outbreak of Listeriosis Associated with Jensen Farms Cantaloupe --- United States, August--September 2011. MMWR 2011; 60(39):1357-1358. Available from: http://www.cdc.gov/mmwr/pdf/wk/mm6039.pdf

  50. References and Resources • Centers for Disease Control and Prevention. Multistate Outbreak of Monkeypox---Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconson, 2003. MMWR 2003;52(23):537-540. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5223a1.htm • Centers for Disease Control and Prevention. Pneumocystis Pneumonia – Los Angeles. MMWR 1981;30(21):1-3. Available from: http://www.cdc.gov/mmwr/preview/mmwrhtml/00043494.htm. • 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. • 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 Principles of Epidemiology. UNC Chapel Hill Gillings School Global of Public Health.

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