Principles of Disease Outbreak Investigation. Contents Definitions Justification –Why investigate an outbreak? Choosing a goal –Control vs. prevention.

Principles of Disease Outbreak Investigation

Contents

• Definitions

• Justification– Why investigate an outbreak?

• Choosing a goal– Control vs. prevention

• Performing an investigation– How do I go about this?

Steps of Investigation

1 Establish case definition2 Confirm reported cases3 Establish endemic level (background rate) of disease4 Establish the existence of an OUTBREAK5 Examine descriptive epidemiological features6 Generate hypotheses7 Test hypotheses8 Collect and test environmental samples9 Implement control/prevention• COMMUNICATE

5 - Descriptive Epidemiology

1. Collect and organize patient/case data2. Characterize patient demographics

– species, age, sex, food source, movement, habitat, lifestyle

3. Epidemic curve– shape of curve - point-source vs.propagated vs. mixed

outbreak

4. Characterize geographically and temporally5. Establish rates

– incidence, prevalence, morbidity vs. mortality

6. Determine risk factors

ReferencesTexts:Veterinary Epidemiology, 2nd Ed. – ThrushfieldApplied Veterinary Epidemiology and the Control of Disease in

Populations – Toma, Dufour et al.Epidemiology, 2nd Ed. – GordisApplication of Quantitative Methods in Veterinary Epidemiology –

Noordhuizen, Frankena et al.Investigation and Mangement of Disease in Wild Animals – WobeserClinical Epidemiology, 2nd Ed. – Sackett et al. Tutorials and Software:Epi Info 2000 and Epi Map 2000 – www.cdc.govInvestigating disease outbreaks, a tutorial – www.cdc.govPublication:Reingold, AL. 1998. Outbreak Investigation – A perspective.

Emerging Infectious Diseases, (4)1.