Principles of Disease Outbreak Investigation

1. Principles of Disease Outbreak Investigation

2. Contents • Definitions • Justification • Why investigate an outbreak? • Choosing a goal • Control vs. prevention • Performing an investigation • How do I go about this?

3. Steps of Investigation • Establish case definition • Confirm reported cases • Establish endemic level (background rate) of disease • Establish the existence of an OUTBREAK • Examine descriptive epidemiological features • Generate hypotheses • Test hypotheses • Collect and test environmental samples • Implement control/prevention • COMMUNICATE

4. 5 - Descriptive Epidemiology • Collect and organize patient/case data • Characterize patient demographics • species, age, sex, food source, movement, habitat, lifestyle • Epidemic curve • shape of curve - point-source vs.propagated vs. mixed outbreak • Characterize geographically and temporally • Establish rates • incidence, prevalence, morbidity vs. mortality • Determine risk factors

5. References Texts: Veterinary Epidemiology, 2nd Ed. – Thrushfield Applied Veterinary Epidemiology and the Control of Disease in Populations – Toma, Dufour et al. Epidemiology, 2nd Ed. – Gordis Application of Quantitative Methods in Veterinary Epidemiology – Noordhuizen, Frankena et al. Investigation and Mangement of Disease in Wild Animals – Wobeser Clinical Epidemiology, 2nd Ed. – Sackett et al. Tutorials and Software: Epi Info 2000 and Epi Map 2000 – www.cdc.gov Investigating disease outbreaks, a tutorial – www.cdc.gov Publication: Reingold, AL. 1998. Outbreak Investigation – A perspective. Emerging Infectious Diseases, (4)1.