1. OIE Terrestrial Animal Health Code (TAHC) Fundamental Concepts
Training Seminar: “The OIE PVS Tool”
16 – 20 April 2012
Beijing, China
Emilio A. León, DVM, PhD 1

2. ANIMAL DISEASE DIAGNOSIS, SURVEILLANCE AND NOTIFICATION
OIE TAHC Section 1 2

3. NOTIFICATION OF DISEASES AND EPIDEMIOLOGICAL INFORMATION
CHAPTER 1.1
NOTIFICATION OF DISEASES AND EPIDEMIOLOGICAL INFORMATION 3

4. Code definition of notification
Procedure by which:
a. the Veterinary Authority informs the Headquarters,
b. the Headquarters inform the Veterinary Authority,
of the occurrence of an outbreak of disease or infection, according to the provisions of Chapter 1.1 of the Terrestrial Code.

5. General considerations
Article 1.1.2
Members shall make available to other Members, through the OIE, whatever information is necessary to minimise the spread of animal diseases and to assist in achieving better worldwide control of these diseases.
To assist in the clear and concise exchange of information, reports shall conform as closely as possible to the official OIE disease reporting format.
In addition to notifying new findings, Members shall also provide information on the measures taken to prevent the spread of disease (stamping out, quarantine, movement restrictions, vaccinations, among others).

6. Requirements - Article 1.1.3 (1)
Veterinary Authorities shall send to the Headquarters:
Notification, within 24 hours, of any of the following events:
first occurrence of a listed disease and/or infection in a country, a zone or a compartment;
re-occurrence of a listed disease and/or infection in a country, a zone or a compartment following a report declared the outbreak ended;
first occurrence of a new strain of a pathogen of a listed disease in a country, a zone or a compartment;
a sudden and unexpected increase in the distribution, incidence, morbidity or mortality of a listed disease prevalent in a country, a zone or a compartment;
an emerging disease with significant morbidity or mortality, or zoonotic potential;
evidence of change in the epidemiology of a listed disease (host range, pathogenicity, strain) in particular if there is a zoonotic impact.

7. Requirements - Article 1.1.3 (2)
Veterinary Authorities shall send to the Headquarters:
Weekly reports subsequent to an immediate notification, to provide further information on the evolution of the event (until the situation has been resolved through either the disease being eradicated or it becoming endemic). In any case, a final report on the incident should be submitted;
a six-monthly report on the absence or presence, and evolution of listed disease;
an annual report concerning any other information of significance to other Members.

8. OIE Commitment Article 1.1.5
The Headquarters shall send to the Veterinary Authorities concerned all received notifications;
the Headquarters shall dispatch to the Delegates information on new outbreaks of listed diseases;
the Headquarters shall prepare an annual report concerning the application of the Terrestrial Code and its effects on international trade.

9. World Animal Health Information System (WAHIS)
WAHIS is the OIE’s world animal health information system.
An access (login, password) is given to each Delegate.
He/she has the possibility to create an access to his/her nominees.
URL address:

10. World Animal Health Information Database (WAHID)
It is the OIE database on animal health, with information available from:
Immediate notifications and follow-up reports submitted by Members;
Six-monthly reports describing the OIE-listed disease situations;
Annual reports providing further background information on animal health, on laboratory and vaccine production facilities, etc.

12. Notification and PVS (1)
FUNDAMENTAL COMPONENT IV: Access to markets
Authority and capability of the VS to provide support in order to access, expand and retain regional and international markets for animals and animal products.
CRITICAL COMPETENCY IV-6: Transparency
Authority and capability of the VS to notify the OIE of their sanitary status and other relevant matters (and to notify the WTO SPS where applicable), in accordance with established procedures.

13. Notification and PVS (2)
TERRESTRIAL CODE REFERENCES:
Article 3.2.8, point 1: the history of compliance of the country with the obligations regarding international notification of animal diseases is consider during VS evaluation. The ability of a VS to elaborate the disease reports including data from surveillance, from monitoring programmes and from disease history is highly relevant to the evaluation.
Article 5.1.3, point 1 (Responsibilities of an exporting country): an exporting country should supply, on request of an importing country, the following information:
animal health situation;
regular and prompt information on the occurrence of notifiable diseases;
details of applied measures to control and prevent relevant listed diseases;
information on the structure of the VS;
technical information, particularly on biological tests and vaccines in use.

14. ANIMAL HEALTH SURVEILLANCE
CHAPTER 1.4
ANIMAL HEALTH SURVEILLANCE 14

15. Definition of surveillance
Is the systematic ongoing collection, collation, and analysis of information related to animal health and the timely dissemination of information to those who need to know so that action can be taken.
Three crucial components:
Systematic: methodical and continuous process for data collection and analysis;
Timely dissemination of information: results must be available and communicated in short time;
Action: interventions must be defined before implementation.

16. Objectives and uses of surveillance
Article 1.4.1
OBJECTIVES
USES
Early detection of exotic or emerging disease;
Description of incidence / prevalence, evolution, geographical and temporal distribution of endemic diseases / infections;
Demonstration of absence of disease / infection.
Detection of disease/infection;
Monitor disease trends;
Facilitate the control of diseases/infections;
Determine priority for control;
Support claims for freedom from disease/infection;
Provide data for use in risk analysis;
Substantiate the rationale for sanitary measures.

17. Critical elements of surveillance (1)
Article 1.4.3
Population: surveillance undertaken over all susceptible species or some of them, including all individuals in the population or part of them;
Case definition: precise definition of infection/disease under surveillance, according to Code standards;
Time frame: surveys should be carried out at a frequency that reflects biology of infection and risk of introduction;
Epidemiological unit: appropriate to meet objectives of surveillance;
Clustering: considered for the design and statistical analysis of data;

18. Critical elements of surveillance (2)
Analytical methodologies: appropriate statistical method, flexible, fully documented and supported by scientific references, transparency;
Testing: sensitivity and specificity of applied method (from sophisticated laboratory tests to field observations) affect results. They should be taken into account for analysis and interpretation of results. Tests validation procedures and results should be stated;
Data collection and management: quality of data is crucial for surveillance. Strongly depends on network of people involved in generating and transferring data from the field to centralized locations, methods for detection of missing or inaccurate data and to address these problems.

19. Types of surveillance (1)
Classification of surveillance may be based in different aspects, including:
The means for data collection: active / passive surveillance;
The disease focus: pathogen-specific / general surveillance;
The procedure for selection of units: structured surveys / non-random data sources.

20. Types of surveillance (2)
OIE Terrestrial Code recommendations on surveillance are classified as follow:
Structured population-based surveys: systematic sampling at slaughter, random surveys (for instance, serology of domestic animals or wildlife);
Structured non-random surveillance activities: disease reporting or notifications; control programmes; targeted testing; ante and post mortem inspections; laboratory records; sentinel units; wildlife disease data…

21. Passive surveillance – Background
Identification and reporting of a suspect case – the first step on passive surveillance – is performed by actors not necessarily belonging to the Veterinary Authority (farmers, private vets, slaughterhouses’ and markets’ workers…);
Validity of the system strongly depends on those actors: awareness and willingness;
List of notifiable diseases;
Procedures to respond to a notification: visit to the affected premise, examination and sampling of affected animals, interdiction, submission of samples to laboratory;
Recording of all received notifications.

22. Structured population-based surveys
Article 1.4.4
Design: based on size, structure and dynamic of the population, the epidemiology of the infection and the resources available;
Sampling: selection of a subset of units representative of the population (risk of bias);
Sampling method: probability sampling is desired in majority of cases. The applied methods should be fully documented;
Sample size: depends on the purpose of the sampling (estimate prevalence or demonstrate absence), the expected prevalence, the desired level of confidence, the desired precision and the performance of the diagnostic test.

23. Structured non-random surveillance (1)
Article 1.4.5
Disease reporting or notification system: data may be used (combined with other data) to demonstrate absence of a disease, for early detection or to generate data for risk analysis. It strongly depends on laboratory support;
Control programmes: these programmes generate data that may contribute to structured surveillance;
Targeted testing: surveillance in subpopulations in which disease is more likely to be found;
Slaughterhouses surveillance: may provide valuable data. Its accuracy depends on nature of disease of interest, training of inspectors and quality of facilities;

24. Structured non-random surveillance (2)
Laboratory records: may be very useful data, depending on the extend of laboratory network. However, the existence if biases is unavoidable and must be taken into account when analysing data;
Biological specimen banks: may contribute to retrospective studies;
Sentinel units: identified individuals of known health status placed in risk areas, that are regularly tested to detect the occurrence of infection. Indicated for diseases with strong spatial clustering such as vector-borne diseases;
Wildlife data: hunters and trappers, road-kills, wild animal meat markets, and other sources. May be of great importance for certain diseases.

25. Structured non-random surveillance (3)
Advantage:
May be a cost-efficient method of early detection, and may increase the level of confidence for disease detection, compared to random surveillance.
Disadvantage:
Some crucial elements, such as sample representative of population, duplication of data, sensitivity and specificity of tests, among others, may difficult interpretation of results.
Analytical methodologies may be may be of high complexity.

26. Surveillance to demonstrate freedom
Article 1.4.6
Freedom from infection implies the absence of the pathogenic agent;
Absolute certainty is impossible to obtain;
Objective: provide adequate evidence (with an acceptable level of confidence) that the infection, if present, does not exceed a specified proportion of the population under surveillance (country, zone or compartment);
OIE officially recognizes freedom from four diseases: FMD, rinderpest, contagious bovine pleuropneumonia (CBPP) and bovine spongiform encephalopathy (BSE).

27. Definitive intervention and report to OIE
Evaluation of surveillance
Sensitivity: probability that the surveillance system will correctly identify the agent in a population when the agent is truly present (probability of no false-negative results);
Specificity: probability that the surveillance system will correctly note the absence of the agent when it is truly not present (probability of no false-positive results);
Timeliness of detection and reporting:
Infection
Report
Intervention
Confirmation
Definitive intervention and report to OIE
Detection
time

28. Surveillance and PVS (1)
FUNDAMENTAL COMPONENT II: Technical Authority and capability
Authority and capability of the VS to develop and apply sanitary measures and science based procedures supporting those measures.
CRITICAL COMPETENCY II-5: Epidemiological surveillance
The authority and capability of the VS to determine, verify and report on the sanitary status of the animal population under their mandate.
This CC is divided in two parts: passive & active surveillance.
It is closely related to other CCs: I.1 (staff), I.7 (physical resources), II.1 (laboratory), II.6 (early detection) and III.6 (interaction with stakeholders).

29. Surveillance and PVS (2)
TERRESTRIAL CODE REFERENCES:
Article 3.2.8, point 2: details of epidemiological surveillance programmes should be considered in the VS evaluation, as well as details on disease control/eradication programmes and disease emergency preparedness (enabling legislation, specific surveillance programmes, contingency plans, compensation provisions, training programmes, incidence and prevalence data and others).
Article 3.2.8, point 3: the presence of a functional animal disease reporting system should be demonstrated.

30. Surveillance and PVS (3)
TERRESTRIAL CODE REFERENCES:
Article , point 7: appropriate requirements for evaluation of animal health and veterinary public health:
Description of and sample reference data from any national animal disease reporting system controlled and operated by the VS;
Description of and sample reference data from other national animal disease reporting systems controlled and operated by other organizations;
Description and relevant data of current official control programmes including: epidemiological surveillance and eradication programmes;
Description and relevant details of animal disease emergency preparedness and response plans;
Recent history of animal disease status: diseases recently eradicated, diseases of which the prevalence has been controlled to a low level or has increased, diseases introduced to the country, emerging diseases.

31. THANK YOU FOR YOUR ATTENTION
Emilio A. León, DVM, PhD 31