1. Principles of Surveillance

2. Content
aim of lecture
context, definitions and history of surveillance
the process
aims of surveillance
criteria for undertaking surveillance
surveillance versus research
steps in setting up surveillance
challenges & opportunities
summary

3. Aim After the lecture, you should be able to… Define: surveillance
its three main components
Describe:
the contexts / historical perspective of surveillance
possible aims
criteria for undertaking surveillance
the difference between surveillance and research
the different steps in setting up surveillance
some challenges and opportunities

4. Definition - dictionary
Surveillance
n. Close observation, especially of a suspected spy or criminal
ORIGIN C19: from Fr., from sur- 'over' + veiller 'watch'
  Source: The Concise Oxford Dictionary. Ed. Pearsall J. Oxford University Press, 2001.

5. Surveillance “The continuing scrutiny of Definition – epidemiology (1)
all aspects of occurrence and spread of disease
that are pertinent to effective control”
Source: Last JM. A Dictionary of Epidemiology (Second Edition). Oxford University Press 1988, New York.

6. Surveillance Definition – epidemiology (2) “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 the timely and regular dissemination
to those who need to know”
Source: Alexander Langmuir (1910 – 1993)

7. First use for Public Health Action
Historical perspective (1)
First use for Public Health Action
William Farr (1807 – 1883)
Superintendent, statistical department, General Register Office, England and Wales
Collected, analysed, interpreted vital statistics
Plotted rise and fall of epidemics of infectious diseases, identifying associations
Disseminated information in weekly, quarterly, and annual reports, medical journals, public press
Prerequisites for surveillance
- organized health care system in a stable government - Roman Empire
- established and accepted classification system for disease and illness -Thomas Sydenham in 17th century
-adequate measurement methods

8. Recognition by World Health Organization
Historical perspective (2)
Recognition by World Health Organization
21st World Health Assembly (1968)
Systematic collection of pertinent data
Orderly consolidation and evaluation of these data
Prompt dissemination of the results to those who need to know
"Information for action"
In 1968, the 21st World Health Assembly focussed on national and global surveillance of communicable disease. In anticipation of this Assembly, Langmuir prepared a working paper in consultation with Karel Raska, the then director of the epidemiological surveillance unit in the Division of Communicable Diseases of WHO, and obtained comments from through out the world.
The report of the Technical Discussions at this World Health Assembly summarized surveillance as…..
And stated that in short, surveillance is information for action.
It was also noted that the concept of surveillance was applicable to public health problems other than communicable diseases, such as cancer, mental illness, atherosclerotic heart disease, drug addictions.

9. Public Health Authority Real world! … expected changes
Surveillance is a cyclical process
Health Care System
Public Health Authority
Reporting
Capture
Data
Event
Real world! … expected changes
Analysis & Interpretation
Dissemination
Information
Intervention

10. design/change vaccination policy
Aims of Surveillance (1)
Actions: examples
detect outbreaks
early warning
design/change vaccination policy
design policy re antimicrobial resistance
evaluate interventions to improve them
certify elimination / eradication
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

11. Public Health aims Aims of Surveillance (2)
Assess public health status (monitor trends, detect outbreaks)
- prevent and control disease
Define public health priorities
- plan considering impact of hazard, exposure, disease
Evaluate public health programmes
- make decisions regarding interventions
Stimulate or inform research
- generate hypotheses, inform methodologie
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

12. Public Health importance
Criteria for undertaking surveillance
Public Health importance / rationale
Public Health importance
burden of disease (incidence / prevalence)
severity, mortality
epidemic potential, threat
costs, socio-economic impact
preventability / opportunities for control
public concern and news-worthiness
Feasibility
costs
availability of data
Feasibility e.g. Feasibility of integrating surveillance of TB drug resistance within the tuberculosis notification system. The linkage of drug susceptibility results with data of the notification allows the representativeness of data to be assessed and the relevant information (particularly age, previous history of tuberculosis treatment, and patient’s geographic origin) to be analysed.
Public concern e.g. Bioterrorism surveillance at Olympic games

13. Surveillance Research Surveillance versus Research
Applies existing knowledge to guide health authorities in the use of known control measures
Directly relevant to monitoring and control needs
Research
Pursues new knowledge from which better control measures will result
Systematic investigation, testing and evaluation, designed to develop or contribute to knowledge
Feasibility e.g. Feasibility of integrating surveillance of TB drug resistance within the tuberculosis notification system. The linkage of drug susceptibility results with data of the notification allows the representativeness of data to be assessed and the relevant information (particularly age, previous history of tuberculosis treatment, and patient’s geographic origin) to be analysed.
Public concern e.g. Bioterrorism surveillance at Olympic games

14. Steps in setting up surveillance (1)
Understand the problem
Identify opportunities for prevention & control
- interventions
- target audience
Set objectives
Specify requirements to meet objectives
Design
- case definitions & indicators
- data needed
- data sources
- data transfer
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

15. Steps in setting up surveillance (2)
Translate information into action
- analyse
- interpret
- disseminate
Evaluate surveillance system
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

16. 1. Understand the problem
Transmission
Exposure
Vector
Environment
Direct
Source of infection
Infection
Reservoir
Disease
Death
Disability
Recovery

17. 2. Identify opportunities for prevention & control
Vector
Environment
Direct
Transmission
Exposure
6. Prevent transmission e.g. universal precautions
1. Vaccination
Source infection
4. Isolation/ treatment
5. Ecological Management
Infection
2. Prophylaxis
Disease
3. Treatment
Reservoir
Recovery
Death
Disability

18. Public Health professionals Government / Politicians
2. Identify opportunities for prevention & control
Target audiences
Public Health professionals
Government / Politicians
Clinicians / Microbiologists / Control of Infection staff
Environmental Health professionals
Health service managers
Health educators / teachers
Public
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

19. Acceptable and Action oriented Realistic Time related
3. Set objectives
SMART
Specific
Measurable
Acceptable and Action oriented
Realistic
Time related
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

20. 3. Set objectives - examples
Vague...
To estimate the prevalence of hepatitis C
To detect outbreaks of measles
Specific, measurable, action-oriented & timed
To assess the prevalence of hepatitis C in France in order to allow planning of specific health care needs for the coming 20 years
To detect early time and place clustering of measles cases in order to ensure timely control of outbreaks
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

21. Keep it as simple as possible!! Timeliness Sensitivity Specificity
4. Requirements of the system
Keep it as simple as possible!!
Timeliness
Sensitivity
Specificity
Completeness of information
Representativeness
Acceptability
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

22. Seek medical attention
5. Design – case definitions
Report
Lab confirmed
Clinical specimen
Seek medical attention
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective
Symptoms
Infected
Exposed

23. - number of resistant strains Denominators
5. Design – examples of data needed
Numerators
- number of cases
- number of resistant strains
Denominators
- population under surveillance
- life births (CRS)
- bacterial isolates (AMR)
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

24. Health service notifications laboratories disease registries
5. Design – data sources (1)
Health service
notifications
laboratories
disease registries
community services
emergency services
screening programmes (antenatal, blood donors)
pharmacy / over the counter drugs
vaccination programmes
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

25. Population statistics
5. Design – data sources (2)
Veterinary
animals (domestic, wild)
food
Environment
water
air
Population statistics
deaths
denominators
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

26. Issues cost representativeness comparability confidentiality
5. Design – data sources (3)
Issues
cost
representativeness
comparability
confidentiality
acceptability
data quality
timeliness
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

27. Existing infrastructure Methods
5. Design – data transfer
Existing infrastructure
Methods
web-based
telephone
Frequency
Zero reporting
en·dem·ic ( n-d m k) adj. 1. Prevalent in or peculiar to a particular locality, region, or people: diseases endemic to the tropics. See Synonyms at native.
From Greek end mos, native, endemic : en-, in; see en-2 + d mos, people; see d - in Indo-European roots.]
Examples
Monitoring trends – endemic disease (hepatitis A)..outbreaks expected every ten years.
Estimating future disease impact – based on incidence data and knowledge of natural history of diseases and using this information together with other relevant information (vaccination coverage) can use this data to estimate the likelihood of recurrence of outbreaks and plan an appropriate intervention. And follow the influence on disease occurrence.
Monitoring progress towards control objective

28. Sampling vs. comprehensive Aggregated vs. individual data
5. Design – addition design issues
Sampling vs. comprehensive
Aggregated vs. individual data
Active vs. passive
Statutory vs. voluntary
Confidential vs. anonymous
Security

29. Analysis Interpretation descriptive (time, place, person) time series
6. Information into Action (1)
Analysis
descriptive (time, place, person)
time series
outbreak detection
molecular epidemiology
geographical information
systems (GIS)
Interpretation
system and data characteristics and changes
chance, bias, truth

30. Dissemination of information
6. Information into Action (2)
Dissemination of information
develop outputs in consultation with users
appropriate level of detail for action
regular review of usefulness
avoid information overload

31. 7. Evaluation of surveillance system
Did the system do what it set out to do?

32. Surveillance – the challenges
Surveillance or research needed?
Reliability
crude and inaccurate
incomplete
accurate denominators
Sustainability
victim of success of control
New threats
emerging infections
bioterrorism
Timeliness
Human Rights
data protection

33. Surveillance – the opportunities
Near patient testing
Less invasive diagnostics (oral fluid, urine)
New molecular typing methods
Electronic patient records
‘New’ data sources
Behavioural surveillance
Syndromic surveillance
On-line, web-based systems
data entry
dissemination of information
New analysis methods
GIS
bio-informatics
modelling

34. Summary Context Definition General process Aims
communicable disease control
epidemiology
Definition
‘information for action’
General process
capture
analysis
dissemination
Aims
Criteria to set up surveillance system
public health importance
feasibility
difference between surveillance and research
Different steps
Challenges and opportunities
In 1968, the 21st World Health Assembly focussed on national and global surveillance of communicable disease. In anticipation of this Assembly, Langmuir prepared a working paper in consultation with Karel Raska, the then director of the epidemiological surveillance unit in the Division of Communicable Diseases of WHO, and obtained comments from through out the world.
The report of the Technical Discussions at this World Health Assembly summarized surveillance as…..
And stated that in short, surveillance is information for action.
It was also noted that the concept of surveillance was applicable to public health problems other than communicable diseases, such as cancer, mental illness, atherosclerotic heart disease, drug addictions.

35. Thank you!