surveillance

Group Discussion on:

SURVEILLANCE

Prepared By

WHAT IS

THE DEFINITION

OF SURVEILLANCE …?

DEFINITIONS OF SURVEILLANCE

• “The continued watchfulness over the distribution and trends of incidence through the systematic collection, consolidation, and evaluation of morbidity and mortality reports and other relevant data, together with dissemination to those who need to know.”

LANGMUIR, 1963


• “Surveillance serves as the brain and nervous system for programs to prevent and control disease.”

D.A. HENDERSON, 1976


“Systematic ongoing collection, collation and analysis of data and the timely dissemination of information to those who need to know so that the action

can be taken”

WHO 2001

KEY ELEMENTS

1. Collection of health data expressly for use in health planning, disease control/ prevention, and/or health promotion.

2. Ongoing collection of data.

3. Timely analysis.

4. Easily understood.

5. Dissemination of results.

6. Action based on results.

7. Periodic evaluation of the system.

(Detels, 1989)

What Are

THE TYPES

OF SURVEILLANCE…?

SU

RV

EIL

LA

NC

EACTIVE

PASSIVE

SENTINEL

WHAT ARE

THE USES

OF SURVEILLANCE…?

Uses of SurveillanceOutbreaks Detection

Human Diseases

Zoonotic Diseases

Food Safety

Drug resistance Organisms

Monitor Changes or

trends in heath factors Disease burden

Emerging diseases

Geographic distribution

Risk group distribution

Health information for

intervention programs

Evaluate effectiveness of

intervention strategies.

WHY SOME

DISEASES ARE UNDER

SURVEILLANCE….?

HOW IS THE OUTBREAK

INVESTIGATED?

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1.Prepare to investigate.

2. Verify the diagnosis and confirm outbreak.

3. Case definition.

4. Case finding.

5. Perform descriptive epidemiology.

6. Hypothesis generation—the how and the why.

7. Evaluate hypothesis thorough statistics.

8. Additional environmental studies.

9. Implement control/prevention measure.

10. Communicate findings.

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EVALUATION …. Of

SURVEILLANCE SYSTEM

SURVEILLANCE SYSTEM EVALUATION

Sensitivity

Timeliness

Representativeness Predictive value

positive Acceptability

Flexibility

Simplicity

Cost/benefit Dissemination

of results Appropriate action taken


• What proportion of “cases” are identified?

• Does the system give an accurate picture of trends and magnitudes?

• Sensitivity


• TimelinessIs information disseminated rapidly enough to permit timely action based on the surveillance system?


• Representativeness

• Do reported cases differ from unreported cases?


• Positive predictive value

• What proportion of those identified actually have the disease or factor?


• Acceptability• Does the system stimulate

the cooperation of respondents?

• Does the process discourage participation?


• Flexibility

• Can changes be easily made in the system to reflect changes in trends, magnitude and other relevant factors?


• Simplicity• Can the system be simplified

and still obtain the necessary information?


• Cost/benefit• Is the system worth the cost?

• Can costs be reduced without sacrificing the essential quality of the system ?


• Dissemination of results

• To decision-makers• To data collectors• To the general public


• Appropriate action taken

• Are appropriate actions taken in response to the surveillance data?

• Does surveillance lead to effective intervention?

Comparison With International Standards

• Use of electronic notification system. • Category of reported cases.• Using of disease specific indicators.• Wide use of active surveillance.• Monitoring of diagnostic efforts.

Comparison With International Standards

• Monitoring circulation of organisms.• Awareness about the surveillance.• Giving frequent and relevant feedback.• Dissemination. • Risk Communication.• Evaluation of surveillance system.

surveillance

Health & Medicine