Surveillance

1. Surveillance Dr. Fortune Sithole, BVSc, MSc, PhD, DACVPM fsithole@rossvet.edu.kn

2. Surveillance definition Miriam-Webster: “originates from the French word surveiller, ‘to watch” and is defined as: “close watch kept over someone or something (as by a detective)”.

3. Surveillance definition • Systematic continuous observation of populations, and collection and analysis of data from many varied sources for: • Rapid detection and timely, appropriate response to important health events and: • Production and communication of valid information about the health and disease status of the population

4. Goals of Animal Health Surveillance • Maintain and improve • Animal health • Animal welfare • Economic viability of animal-based food production systems • Protection of public health • Control of zoonotic and foodborne diseases

5. Purpose of Surveillance • Rapid detection of disease outbreaks • Support Dz control/eradication • Assess population health and safety of food • Produce information about disease • Evaluate disease control/biosecurity programs

6. Purpose of Surveillance: • Rapid detection of disease outbreaks • Endemic, foreign, emerging • Early detection prevents catastrophic losses and costs • Direct costs: dead animals, treatment for sick animals, lost productivity • Indirect costs: lost markets, lost consumer confidence, losses in tourism, loss to rural economies: agriculture has a 3–4 times multiplier effect • Example: The FMD outbreak in the UK (2001)

7. Purpose of Surveillance: • Support dz control/eradication • During an outbreak • Situational intelligence • Identify suspect or infected farms for stamping out • Control eradication program • Identify infected farms for control measures • Example test and slaughter programs

8. Purpose of Surveillance • Assess the health of populations and safety of food products • OIE member nations obligated to scientifically estimate the disease risk associated with their animals and animal products • Amount of dz or freedom from dz • Essential for trade • Requires surveillance, well-trained veterinary service, diagnostic laboratory system, legislation to facilitate disease control

9. Purpose of Surveillance • Assessment of the health of populations and safety of food products • OIE member nations are required to report the occurrence of listed and emerging diseases • Requires OIE-acceptable surveillance • Borders will close if trade-limiting disease is detected, but open faster with good surveillance • Borders can be closed if a nation has substandard surveillance, even if no disease has been detected

10. Purpose of Surveillance • Produce information about diseases: their importance, changing distribution, and changing risk factors • Information used for: • Setting research priorities • Emergency preparedness • Government-directed disease control programs • Veterinarians and farmers to manage disease

11. Purpose of Surveillance • Evaluate effectiveness of disease control, biosecurity, and border security programs • Surveillance detects failure of biosecurity and border security programs

12. Components of surveillance

13. Surveillance has three components • Systematic continuous observation of populations, and collection and analysis of data from many varied sources for: • Rapid detectionand timely, appropriate response to important health events and • Production and communication of valid information about the health and disease status of the population 1. Detection 2. Response 3. Communication

14. 1. Detection • Observation of a population or collection, analysis, and interpretation of data from a population • Disease outbreak investigation and diagnostic pathology are part of detection. • Goal: timely detection or identification of • Important disease events in the population • FAD incursions, emerging Dzes, endemic Dz outbreaks • Significant changes in the health status of the population • Significant changes in risk factors for diseases in the population

15. 2. Response • The immediate response to disease outbreaks and events is considered part of surveillance • Pre-determined/defined response to a defined event • Example: the immediate response to a case of FMD • Example: Holding a carcass with lesions/tumors • Goal: Timely, appropriate response to Dz events • Minimize the impact (loss of animals, productivity, markets) • Minimize the cost of the response

16. 3. Information Production and Communication Goal: Produce and communicate timely, accurate info about the health/dz status of the population • For outbreak response • Situational intelligence during an outbreak (define the problem) • Information for emergency preparedness • For dz control and management • Changing patterns of endemic diseases • Changing patterns of risk factors for disease • Absence of dz • Effectiveness of biosecurity, border surveillance, disease eradication and control programs

17. Categories And Types of Surveillance

18. Broad Categories of Surveillance • Animal health surveillance • Surveillance of animals for diseases of importance to animals and people • Public health surveillance • Surveillance of people for human diseases • Biosurveillance • Surveillance of humans, animals, and plants for diseases affecting any or all of them • Food safety surveillance • Surveillance of food production chains and people for food safety risks and foodborne disease

19. Types of Surveillance • Passive surveillance • Active surveillance • Sentinel surveillance • Targeted surveillance

20. Types of Surveillance • Passive Surveillance • Submission is initiated by and at the discretion of the sample/data provider • Veterinary/health authority does very little to select subjects for sampling or information • Reportable dz programs: Veterinary/health authorities expect/obligate clinicians (or laboratories) to send in reports; they don’t actively go out and select who will be sampled or provide information • Little or no control over who provides samples/data • Passive surveillance is the most common type of surveillance

21. Types of Surveillance • Passive surveillance examples • Reportable disease programs • While mandatory, they are passive because farmers, veterinarians, physicians, laboratories initiate the reporting… at their discretion. • BSE, Scrapie, CWD surveillance, rabies, foodborne illness • WAHID or WAHIS displays diseases reported to the OIE • Sero-surveys at auction markets and slaughter plants • Animals are presented for slaughter or sale at the discretion of the owner. • Diagnostic laboratory submission surveillance • Owners/vets/physicians submit samples for diagnostic testing at their discretion.

22. Types of Surveillance • Passive surveillance examples • Real-time surveillance (Syndromic = pre-diagnosis) • Emergency room/ambulance records • Physician/Veterinary practice medical records • Sales of pharmaceuticals • Absenteeism from schools, public service • Pro-med mail • Digital disease surveillance • Healthmap • Google flu trends

23. Types of Surveillance • Passive Surveillance • Pros: • Reportable disease programs provide continuous surveillance • Great for early detection of important, obvious, easy to diagnose diseases… only if veterinarians are well trained to recognize the disease • Laboratory surveillance can detect emerging diseases • Inexpensive • Cons: • Little control over who provides data/samples • Not a representative sample of the population • Won’t work for less-valued animals that don’t use veterinary services • If disease is stigmatized, farmers won’t report

24. Types of Surveillance • Active Surveillance • Involves the committed effort of the veterinary/health authority to identify subjects for data or samples • They initiate the sample/data collection by identifying the surveillance subjects and initiate sample/info collection • They call, visit, etc., the sample/data providers and actively seek out cases of disease or data • Examples of some surveys • Individuals in the population are identified and picked (often randomly) by the surveillance practitioner for inclusion. It is active if the surveillance practitioner goes out to visit farms or people (i.e., actively puts time and effort into collecting the samples and controlling who submits).

25. Types of Surveillance • Active Surveillance • Pros • Can be representative of the population • Can make valid estimates of the amount of disease and importance of disease in the population • Requires being able to identify all individuals in the population • Cons • Very expensive, labor intensive • Usually done once or intermittently • Not good for early detection of disease outbreaks or emerging diseases • May not be representative of the population • If you can’t identify all individuals in the population, you can’t get a representative sample.

26. Types of Surveillance • Sentinel Surveillance • A small group is monitored as an indicator of the greater population health or disease risk • A site, a group, even a different species • Example: sentinel farms, veterinary practices, physicians • Example: chickens act as sentinels for estimating the risk to human populations from Eastern equine encephalitis • Example: horses, wild birds, and mosquitos act as sentinels for the risk to human populations from West Nile Virus

27. Types of Surveillance • Sentinel Surveillance • Pros • Less expensive than monitoring the whole population • Often the only method available • Allows intensive, multiple testing and early warning • Cons • May not be representative of the population

28. Types of Surveillance • Targeted Surveillance • Targets a specific segment of the population to enhance detection of disease • Example: Targeting downer cattle for BSE testing • Pros • Enhanced efficiency, reduced cost • Cons • May not be representative of the population