Surveillance and monitoring

Question 1

Surveillance & monitoring - definition

Answer 1

Monitoring: routine collection of information on disease, productivity and other characteristics Surveillance: gathering, recording and analysis of data for dissemination so that action can be taken to control disease

Question 2

Surveillance - functions

Answer 2

1. Demonstrate freedom of disease
2. Determine distribution and occurrence of disease
3. Early detection of exotic or EIDs
4. Monitor disease trends
5. Evaluate control programs
6. Provide data for use in risk analysis & research

Question 3

Surveillance - types

Answer 3

1. Passive vs active
2. Pathogen specific vs general
3. Structured population-based surveys vs structured non-random (opportunistic) data sources

Question 4

Structured population based surveys (surveillance)

Answer 4

1. Census vs sample (selected via non-probability or probability based methods)
2. If survey, define purpose (prevalence survey vs freedom of disease survey)
3. Define units of analysis
4. Calculate sample size based on purpose of the survey
5. Repeat periodically

Question 5

Structured non-random data sources (surveillance)

Answer 5

1. Disease reporting or notification systems (used for making claims about animal health status, generating data for risk analysis, early detection; use sensitive laboratory tests)
2. Control programs and health schemes
3. Targeted testing and screening e.g. testing culled/dead animals, those exhibiting clinical signs
4. Ante-mortem and post-mortem inspection (subject to bias since good coverage for particular age groups/classes and geographical areas only; requires traceability to provide herd-level coverage)
5. Lab investigation records (national, accredited, university and private sector labs; need standardized lab procedures/interpretation/recording; requires traceability)
6. Sentinel units (vectorborne disease, targeted to specific geographic areas)
7. Field observations
8. Farm production records
9. Wildlife data

Question 6

Wildlife data sources (surveillance)

Answer 6

Hunters and trappers, road-kills, wild animal meat markets, sanitary inspection of hunted animals, morbidity and mortality observations by the general public, wildlife rehabilitation centres, wildlife biologists and wildlife agency field personnel, farmers and other landholders, naturalists and conservationists

Question 7

Surveillance to demonstrate freedom of disease -

Answer 7

1. Historically free: Can be recognized as free without applying pathogen-specific surveillance program if disease never occurred or was eradicated more than 25 years ago
2. Last occurrence within previous 25 years: If disease was eradicated within 25 years, pathogen specific surveillance is needed.

In both cases, freedom can be declared provided that in the last 10 years:

• Disease has been notifiable
• Early detection system has been in place
• No vaccination has been carried out
• Infection is not established in wildlife

Question 8

Surveillance for distribution and occurrence of infection - uses (2), data collected

Answer 8

Uses:

1. assess progress and aid in decision making in the control or eradication
2. also has relevance for the international movement of animals and products.

Data collected on many variables (prevalence/incidence, morbidity/mortality, risk factors, % immunized etc)

Question 9

Surveillance - mechanisms

Answer 9

1. Voluntary notification
2. Mandatory notification
3. Outbreak investigation
4. Sentinel surveillance
5. Structured surveys
6. Census