1) The document discusses surveillance in public health and describes its key components and purposes. Surveillance involves the systematic collection, analysis, and interpretation of health data to provide information for action. 2) An effective surveillance system is simple, flexible, timely, and produces high-quality data. It addresses an important public health problem and accomplishes its objectives of understanding disease trends, detecting outbreaks, and evaluating control measures. 3) The document outlines how to establish a surveillance system, including selecting priority diseases, defining standard case definitions, and developing regular reporting and data dissemination processes. Both passive and active surveillance methods are described.

1. SurveillanceDr. Akhilesh BhargavaMD, DHA, PGDHRMProf. Community Medicine &Director-SIHFW, Jaipur

2. Public Health ApproachImplementation:How do youdo it?InterventionEvaluation:Whatworks?Risk FactorIdentification:What is the cause?Surveillance:What is the problem?ResponseProblemAkhilesh Bhargava2

3. SurveillanceInformation for ActionSurveillance is the bridge between what we think is happening and What actually is happeningAkhilesh Bhargava3

4. Surveillance ? “a system of close, continuousobservation of all aspects of the occurrence & distribution of a disease through systematic Collection, Tabulation, Analysis and Dissemination (Timely) of all relevant data pertaining to that Disease/event”. Descriptive (purposeful)Action (Public health policy)Akhilesh Bhargava4

5. Purpose:General- Reducing mortality/ morbidity through timely prevention & control Specific-Understanding problem NHD, Magnitude, TrendDefine priorities

6. Decide objectives

7. Determine strategies

8. Evaluate control/ prevention

9. Suggest further researchAkhilesh Bhargava5

10. Surveillance helps in:Understanding Natural HistoryDeciding levels of existence of diseaseExplaining changes in pattern with timeIdentifying Changes in agent characteristicsMeasuring efficacy of control measureForecasting trendsAkhilesh Bhargava6

11. Uses of Public Health SurveillanceEstimate magnitude of the problemDetermine geographic distribution of illnessPortray the natural history of a diseaseDetect epidemics/define a problemGenerate hypotheses, stimulate researchEvaluate control measuresMonitor changes in infectious agentsDetect changes in health practicesFacilitate planningAkhilesh Bhargava7

12. Types:Routine

13. Active (agency solicited)

14. Passive (provider initiated)

15. Sentinel

16. Reporting by specified units from defined area

17. Denominator absent

18. Focused (Situation / Process / Area)

19. Case/outbreak investigations

20. Special surveys-Nutritional surveillance Akhilesh Bhargava8

21. Routine surveillanceThrough Out Patient Dept. of Health facilities (Passive) Wait & See who reports whatField surveys (Active) Go & Get Data/ Information Issues- Representative? Home treatment? Number of Health Facilities reporting Completeness of reportingAkhilesh Bhargava9

22. PassiveSimpleLess burdensomeInexpensiveMay not be representativeMay fail to identify outbreaksAkhilesh Bhargava10

23. ActiveAssures complete reportingCan be used with specific investigationsCan be done for brief periodsRequires skilled personnelMay be perceived as invasiveExpensiveAkhilesh Bhargava11

24. Sentinel Surveillance Monitoring of key health events through sentinel:SitesEventsProvidersVectors/animalsAkhilesh Bhargava12

25. Sentinel surveillanceReporting of health events by selected Units/ Professionals representing a geographic areaCould be active or PassiveOnly a small number of units selectedSelected units report all cases for a specific time periodReports include additional informationEasier to maintain Quality & RegularityDenominator absentData collected are Not representative & NO generalizationAkhilesh Bhargava13

26. Good Surveillance system: Simplicity- ease of operation- minimum paper work simple definitions using existing system Flexibility

27. Acceptability

28. Sensitivity

29. Predictive value

30. Representative

31. Timeliness

32. Regularity

33. Data quality-complete/reliable/accurate

34. Cost-effectivenessAkhilesh Bhargava14

35. Initiating a Surveillance systemActivities:Choose a disease that has proved control measures availableDefine how data collected shall be usedSet a standard case definitionUse existing systemVisit those who supply DataDevelop a data baseDevelop a regular reporting system for distribution (Feed back)Akhilesh Bhargava15

36. Disease selection for surveillanceEligibility criteria:Public Health problem (Quantitative BOD)

37. ImpactClinical spectrum (Severity)MortalityCommunicability (Epidemic potential)

38. Preventability (in terms of feasibility & cost)

39. Risk perception Global health organizationsNational authorityNGOPeoplePolitical pressureAkhilesh Bhargava16

40. Prerequisites of an effective surveillance systemStandard case definition

41. Enumeration of Reporting units

42. System For Disease SurveillanceNotifiable disease reporting SystemLaboratory based surveillanceHospital based surveillancePopulation based surveillanceAkhilesh Bhargava17

43. Standard Case DefinitionMay not necessarily be the same as what clinician perceives

44. Depends on-SeverityCertainty of DiagnosisConfirmedProbablePossibleSuspectNon-casePurposeSensitivitySpecificityAkhilesh Bhargava18

45. Systems of Disease surveillanceNotifiable disease reporting SystemMorbidityMortalityCase investigation Epidemic reportingField investigationDrug and Biological useLaboratory based surveillance

46. Hospital based surveillance

47. Population based surveillanceSurveysServicesAkhilesh Bhargava19

48. Sources of surveillance dataMortalityMorbidityCase reportsEpidemic reporting Epidemic field investigationsLaboratory reportingSurveysVector distribution studiesBiologics & drug distributionDemographic & environmental dataNews mediaAkhilesh Bhargava20