What is an outbreak?

1. Outbreak Alert and Response Systems: a reviewFebruary 2004Ayana Yeneabat, MD, MPHEpidemiologist, WHO

2. What is an outbreak? • A public health emergency! • A political emergency! • An economic emergency! • An unusual event! • An event requiring rapid action! • Surveillance failure! • Control failure! • An opportunity !

3. Influenza pandemics 20th century Credit: US National Museum of Health and Medicine 1918: “Spanish Flu” 1957: “Asian Flu” 1968: “Hong Kong Flu” 20-40 million deaths 1-4 million deaths 1-4million deaths A(H1N1) A(H2N2) A(H3N2)

4. DF/DHF re-emerging infectious diseases No report Total population of the SEA Region = 1.5 billion Total population at risk = 1.3 billion (87%)

6. Source: FAO

7. Ebola (Viral Haemorrhagic Fever) in Africa

8. What is outbreak management? The process of anticipating, preventing, preparing for, detecting, responding and controlling disease outbreaks in order that health and economic impacts are minimised

9. Surveillance: Information for Action

10. Components of Effective Outbreak Management • Anticipation/Prediction • Preparedness • Early warning/Surveillance • Effective and co-ordinated response • Evaluation

11. Components of Effective Outbreak Management • Anticipation/Prediction • Preparedness • Early warning/Surveillance • Effective and co-ordinated response • Evaluation

12. Reported cases of encephalitis in Nepal, 1997-1998: Prediction/trends 350 1997 300 250 1998 200 Cases 150 100 50 0 1 5 9 13 17 21 25 29 33 37 41 45 49 Source: EWARS Week No

13. RVF EPIZOOTICS Davies et al. 1985. Bull. WHO. 63:941-3. Effect of rainfall in producing RVF Epizootics in Kenya 1950-1982: Forecast/Metrological Data Composite rainy days x rainfall surplus (12 month accumulated figure)

14. Components of Effective Outbreak Management • Anticipation/Prediction • Preparedness • Early warning/Surveillance • Effective and co-ordinated response • Evaluation

15. Epidemic Preparedness and Response Plan • What should be done ? • Who should do it ? • What resources or supplies will be required ?

16. Components of Epidemic Preparedness 1 Established planning and co-ordination mechanism 2. Agreed priorities 3. Implemented epidemic preparedness plan (surveillance, response etc) 4. Functional early warning system 5. Capacity for rapid implementation of plans

17. Components of Effective Outbreak Management • Anticipation/Prediction • Preparedness • Early warning/Surveillance • Effective and co-ordinated response • Evaluation

18. What is the Early Warning/surveillance objective for outbreaks? • To predict, detect and confirm outbreaks of public health importance in a timely fashion and to disseminate that information to those who need to know so that effective public heath action can be taken

19. What are the components of an effective early warning system ? • Small number of priority diseases • Syndromic reporting • Simple case definitions • Processes for dealing with rumours • Rapid case investigation and sampling • Rapid laboratory confirmation • Standard procedures for information sharing and initiation of response • Preparedness plans in place

20. Outbreak Alerts: Thresholds • Absolute numbers • 1 case of AFP or rabies • Relative values compared to similar period • Need to establish trend • Absolute rate over a period • Population at risk and index cases (2/100,000) • Statistical cut-offs • Time series modeling (deviations)

21. First Case Detection/ Reporting Lab confirmation Response Opportunity for control CASES DAY Outbreak Detection and Response: no functional EWS

22. Detection/ Reporting First Case Confirmation Response Opportunity for control CASES DAY Outbreak Detection and Response: functional EWS

23. How can early warning systems contribute to outbreak management ? • Establish the expected • Predict the future • Detect the unexpected (early warning) • Verify/Confirm the existence of an outbreak • Monitor the evolution of an outbreak • Tell you the when outbreak is over • Monitor control programme!

24. Early warning: tracking of unusual events; Orissa, India, 2003

25. Mapping of Reported Disease Outbreaks, Orissa, MIS/OMDSS, 2003

26. Components of Effective Outbreak Management • Anticipation/Prediction • Preparedness • Early warning/Surveillance • Effective and co-ordinated response • Evaluation

27. Diagnosis verified ? clinical + laboratory Link between cases? Expected numbers? Routine surveillance Clinical / Laboratory General public Media Detection Confirm outbreak and diagnosis

28. Outbreak confirmed Immediate control measures? Further investigation? Control can happen at any time during the outbreak! But you still may need to investigate

29. Point source Examples of epidemic curves Multiple waves -person to person or further outbreak Continuing common source

30. Post outbreak Tasks • Prepare written report • Communicate public health messages • Convince public health policy • Evaluate performance

31. PREPAREDNESS OUTBREAK CONTROL Investigate Committee Priorities Plan Co-ordination Responsibilities Resources Supplies Training Surveillance Rapid Response Detect & Confirm Analyse Respond Predict & Prevent Treat Control Evaluate

32. Attributes: detection, alert, response • EWARN, Sudan • DEWS, Pakistan • KO-SURV, Kosovo • EWORS, Indonesia • EAST TIMOR • EWARS, Nepal • Global outbreak alert and response network (GOARN) • Global Public Health Intervention Network (GPHIN) • Orissa-MDSS/MIS/Early Warning • Gujarat/Kachchh District Early Warning System • NSPCD/IDSP In India: focus on early epidemics

33. Hallmark: information for prompt action • Timely Information • Real time transfer of information • Sound Analysis • Instant and meaningful Interpretation • Prompt and effective response • Feedback • Simple and flexible to context

34. Partnership: Key for EWS