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Diseases in Nature Conference

Diseases in Nature Conference. Disease Outbreak Investigations. Austin, Texas, June 11 th 2007. John Herbold DVM, MPH, PhD, DACVPM, FACE Center for Biosecurity & Public Health Preparedness University of Texas School of Public Health. Disease Outbreak Investigations.

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Diseases in Nature Conference

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  1. Diseases in Nature Conference Disease Outbreak Investigations Austin, Texas, June 11th 2007 John Herbold DVM, MPH, PhD, DACVPM, FACE Center for Biosecurity & Public Health Preparedness University of Texas School of Public Health

  2. Disease Outbreak Investigations

  3. Disease Outbreak Investigations “...So far this appears to be an isolated case” CDC Press Release on Florida Anthrax Case

  4. Disease Outbreak Investigations

  5. A ‘Cutting Edge’ Review of Disease Outbreak Investigation Strategies

  6. OUTLINE OF THE INVESTIGATION OF AN EPIDEMICMausner & Bahn, Epidemiology An Introductory Text, 1985 ...an exciting exercise in medical detection ...painstaking accumulation of data in the field ...careful analysis of data ...flashes of insight ...systematic outline

  7. Mausner & Bahn Outline • Preliminary Analysis • Verify the Diagnosis • Verify the Existence of an epidemic • Describe the Epidemic by PPT • Formulate and Test Hypotheses

  8. Mausner & Bahn Outline • Possible Further Investigation and Analysis • Search for Additional Cases • Analyze the Data • Make a Decision [Hypotheses Considered] • Intervention and Follow-up

  9. Mausner & Bahn Outline • Report of the Investigation • include discussion of factors • evaluation of measures used for control • recommendations for prevention

  10. ‘strategy’ to investigate the etiology of disease I. Confirm the existence of a health problem A. Define cases in terms of person, place, and time B. Describe what you see.............. C. Discuss explanations for associations that you see II. Discuss possible causes, etiology, of the problem A. Assess information, literature, consult specialists B. Generate possible/potential hypotheses.... C. Display ('examine') the evidence (information) III. Test specific hypothesis (ses) IV. Action (intervention, prevention, clinical trial) V. Experimental (laboratory, animal models, etc.) VI. Review I through V and develop unifying theory VII. Publish a report ... present in a public forum VIII. Re-confirm (that's why its called re-search) Reference: Roht et al,

  11. “Ten” Steps For Investigating An Epidemic Prepare for field work (re – search the literature; talk to experts) Establish the existence of an outbreak (endemic, epidemic, cluster, outbreak) Verify the diagnosis (clinical, laboratory, epidemiologic) Define and identify cases Establish a case definition Identify and count cases Perform descriptive epidemiology (person, place, time) Develop hypotheses Evaluate Hypotheses Reconsider/refine hypotheses and execute additional studies Implement control and prevention measures Communicate findings Reference: CDC Satellite Broadcast Course, 1993

  12. Time to get to work !!!

  13. Time to get to work !!! • Late Friday afternoon... Of course • Phone Call to LHD from Local Physician • Looks like hepatitis... • 1 adult patient who also tells Doc... • 2 colleagues at work (law office downtown) • Diagnosed this week also... What first steps should be taken???

  14. What first steps should be taken??? • Read up on hepatitis • Exact dates of onset • Interview 3 cases (travel hx) • Line listing of patients (demographics) • Interview co-workers (jobs, restaurants, social) • What’s community experience with hepatitis • Extent of outbreak outside law office • Number of cases over past year • Anything else??

  15. Disease Outbreak Investigations Video One

  16. Know .. 3 cases of hepatitis A within the week Hx of only 12 cases last year Anytown USA What would you use for a case definition ? What would you do next ?

  17. Know .. 3 cases of hepatitis A within the week Hx of only 12 cases last year Anytown USA What would you use for a case definition ? • Clinical & Laboratory parameters • (Person) • 3 cases date of onset plus/minus 3 days • (Time) • People in Law Office • (Place)

  18. Know .. 3 cases of hepatitis A within the week Hx of only 12 cases last year Anytown USA What would you do next ? • Expand search for cases • (law firm and family members) • Look @ community experience • (labs, hospital, cases past month) • Other suggestions..... • This looks like a ‘lot of work’ !

  19. Disease Outbreak Investigations Video Two

  20. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county • What type of outbreak is this? • point source • continuing common source • person to person • What do you think caused it? • How would you check your hypothesis?

  21. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county • What type of outbreak is this? • point source (time/place cluster) ... food .... water • continuing common source (#’s) ... water • person to person (incubation period)

  22. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county • What do you think caused it? • Food • Water • Other ?

  23. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county How would you check your hypothesis? • Municipal water system records • Food histories of patients • Other ?

  24. Disease Outbreak Investigations Video Three

  25. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county Most likely foodborne How would you design studies to evaluate various foodborne routes? What foods would you suspect and why?

  26. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county Most likely foodborne • How would you design studies to evaluate various foodborne routes? • Cases and co-workers as controls • Where & how often did you eat downtown • Food preferences

  27. Know .. 32 cases of hepatitis A within the week Not confined to law office Live all over the county Most likely foodborne • What foods would you suspect and why? • Salads • Fresh fruits • Uncooked vegetables • Seafood (raw) • Pizza ?

  28. Disease Outbreak Investigations Video Four

  29. Louisville KY 1988 • more than 200 cases confirmed • immune globulin given to contacts • 13% of cases hospitalized ! • little secondary spread • no children “Adult Outbreak”

  30. Reginald Finger MD,MPH KY State Epidemiologist Melodious Voice Mark Garmack UAB SPH PRODUCED BY Alabama Department of Health Principles of Epidemiology By Satellite May 20th 1993

  31. HOW DID WE DO ?????

  32. One World One Medicine One Ecology

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