| Module 12 Risk Analysis and OIEV. Welte Animal Production and Health Division |
To review the provisions and principles of the Import Risk Analysis, Part 1 Section 1.4 of the International Animal Health Code. A chapter by chapter and sometimes article by article review with the corresponding explanations is conducted.
12.1 General considerations
12.2 Chapter 1.4.2. Guidelines for risk analysis
12.3 Chapter 1.4.3. Evaluation of veterinary services
12.4 Chapter 1.4.4. Zoning and regionalization
12.5 Chapter 1.4.5. Surveillance and monitoring of animal health
The importation of animals and animal products involves a degree of disease risk to the importing country. This risk may be represented by one or several diseases or infections.
The principal aim of import risk analysis is to provide importing countries with an objective and defensible method of assessing the disease risks associated with the importation of animals, animal products, animal genetic material, feedstuffs, biological products and pathological material. The analysis should be transparent. This is necessary so that the exporting country is provided with clear reasons for the imposition of import conditions or refusal to import.
Transparency is also essential because data are often uncertain or incomplete and, without full documentation, the distinction between facts and the analyst's value judgements may blur.
This module discusses Section 1.4 of the International Animal Health Code dealing with import risk analysis. Section 1.4.1. alludes to OIE's role with respect to the World Trade Organization (WTO) Agreement on the Application of Sanitary and Phytosanitary Measures (the so-called SPS Agreement), provides definitions and describes OIE's procedure for settlement of disputes.
Section 1.4.2. provides guidelines and principles for conducting transparent, objective and defensible risk analyses for international trade. The components of risk analysis described in that Section are hazard identification, risk assessment, risk management and risk communication (Figure 1).
Risk assessment is the component of the analysis which estimates the risks associated with a hazard. Risk assessments may be qualitative or quantitative. For many diseases, particularly for those diseases listed in the Code where there are well developed internationally agreed standards, there is broad agreement concerning the likely risks. In such cases it is more likely that a qualitative assessment is all that is required. Qualitative assessment does not require mathematical modelling skills to carry out and so is often the type of assessment used for routine decision making. No single method of import risk assessment has proven applicable in all situations, and different methods may be appropriate in different circumstances.
The process of import risk analysis usually needs to take into consideration the results of an evaluation of veterinary services, zoning and regionalization and surveillance systems in place for monitoring of animal health in the exporting country. These are described in Sections 1.4.3. through 1.4.5. in the Code.
The WTO SPS Agreement encourages WTO Members to base their sanitary measures on international standards, guidelines and recommendations, where they exist. Members may choose to adopt a higher level of protection than that provided by international texts if there is a scientific justification or if the level of protection provided by the relevant international texts is considered to be inappropriate. In such circumstances, Members are subject to obligations relating to risk assessment and to a consistent approach of risk management.
The SPS Agreement encourages Governments to make a wider use of risk assessment: WTO Members shall undertake an assessment as appropriate to the circumstances of the actual risk involved.
The SPS Agreement recognizes the OIE as the relevant international organization responsible for the development and promotion of international animal health standards, guidelines, and recommendations affecting trade in live animals and animal products.
Acceptable risk: Risk level judged by Member Countries to be compatible with the protection of animal and public health within their country.
Commodity: Animals, animal products, animal genetic material, feedstuffs, biological products and pathological material.
Consequence assessment: See point 3 of Article 1.4.2.4.
Exposure assessment: See point 2 of Article 1.4.2.4.
Hazard: In the context of the Code, any pathogenic agent that could produce adverse consequences associated with the importation of a commodity.
Hazard identification: The process of identifying the pathogenic agents which could potentially be introduced in the commodity considered for importation.
Implementation: See point 3 of Article 1.4.2.6.
Monitoring: See point 4 of Article 1.4.2.6.
Option evaluation: See point 2 of Article 1.4.2.6.
Qualitative risk assessment: An assessment where the outputs on the likelihood of the outcome or the magnitude of the consequences are expressed in qualitative terms such as high, medium, low or negligible.
Quantitative risk assessment: An assessment where the outputs of the risk assessment are expressed numerically.
Release assessment: See point 1 of Article 1.4.2.4.
Review: See point 4 of Article 1.4.2.6.
Risk: The likelihood of the occurrence and the likely magnitude of the consequences of an adverse event to animal or human health in the importing country during a specified time period.
Risk analysis: The process composed of hazard identification, risk assessment, risk management and risk communication (see Figure 1).
Risk assessment: The evaluation of the likelihood and the biological and economic consequences of entry, establishment or spread of a pathogenic agent within the territory of an importing country (see Articles 1.4.2.3. and 1.4.2.4.).
Risk communication: Risk communication is the interactive exchange of information on risk among risk assessors, risk managers and other interested parties (see Article 1.4.2.7.).
Risk estimation: See point 4 of Article 1.4.2.4.
Risk evaluation: See point 1 of Article 1.4.2.6.
Risk management: The process of identifying, selecting and implementing measures that can be applied to reduce the level of risk (see Articles 1.4.2.5. and 1.4.2.6.).
Sanitary measure: Measures such as those described in each Chapter of the Code which are used for risk reduction and are appropriate for particular diseases.
Sensitivity analysis: The process of examining the impact of the variation in individual model inputs on the model outputs in a quantitative risk assessment.
Transparency: Comprehensive documentation of all data, information, assumptions, methods, results, discussion and conclusions used in the risk analysis. Conclusions should be supported by an objective and logical discussion and the document should be fully referenced.
Uncertainty: The lack of precise knowledge of the input values which is due to measurement error or to lack of knowledge of the steps required, and the pathways from hazard to risk, when building the scenario being assessed.
Variability: A real-world complexity in which the value of an input is not the same for each case due to natural diversity in a given population.
OIE shall maintain its existing voluntary in-house mechanisms for assisting Member Countries to resolve differences. In-house procedures which will apply are that:
1. Both parties agree to give the OIE a mandate to assist them in resolving their differences.
2. If considered appropriate, the Director General of the OIE recommends an expert, or experts, and a chairman, as requested, agreed by both parties.
3. Both parties agree on the terms of reference and working programme, and to meet all expenses incurred by the OIE.
4. The expert or experts are entitled to seek clarification of any of the information and data provided by either country in the assessment or consultation processes, or to request additional information or data from either country.
5. The expert or experts shall submit a confidential report to the Director General, who will transmit it to both parties.
An import risk analysis begins with a description of the commodity proposed for import and the likely annual quantity of trade. It must be recognized that whilst an accurate estimate of the anticipated quantity of trade is desirable to incorporate into the risk estimate, it may not be readily available, particularly where such trade is new.
Hazard identification is an essential step which must be conducted before the risk assessment.
The risk assessment process consists of four interrelated steps. These steps clarify the stages of the risk assessment, describing them in terms of the events necessary for the identified potential risk(s) to occur, and facilitate understanding and evaluation of the outputs. The product is the risk assessment report which is used in risk communication and risk management.
The relationships between risk assessment and risk management processes are outlined in Figure 2.
The hazard identification involves identifying the pathogenic agents which could potentially produce adverse consequences associated with the importation of a commodity.
The potential hazards identified would be those appropriate to the species being imported, or from which the commodity is derived, and which may be present in the exporting country. It is then necessary to identify whether each potential hazard is already present in the importing country, and whether it is a notifiable disease or is subject to control or eradication in that country and to ensure that import measures are not more trade restrictive than those applied within the country.
Hazard identification is a categorization step, identifying biological agents dichotomously as potential hazards or not. The risk assessment may be concluded if hazard identification fails to identify potential hazards associated with the importation.
The evaluation of the veterinary services, surveillance and control programmes and zoning and regionalization systems are important inputs for assessing the likelihood of hazards being present in the animal population of the exporting country.
An importing country may decide to permit the importation using the appropriate sanitary standards recommended in the Code, thus eliminating the need for a risk assessment.
1. Risk assessment should be flexible to deal with the complexity of real life situations. No single method is applicable in all cases. Risk assessment must be able to accommodate the variety of animal commodities, the multiple hazards that may be identified with an importation and the specificity of each disease, detection and surveillance systems, exposure scenarios and types and amounts of data and information.
2. Both qualitative and quantitative risk assessment methods are valid.
3. The risk assessment should be based on the best available information that is in accord with current scientific thinking. The assessment should be well documented and supported with references to the scientific literature and other sources, including expert opinion.
4. Consistency in risk assessment methods should be encouraged and transparency is essential in order to ensure fairness and rationality, consistency in decision-making and ease of understanding by all the interested parties.
5. Risk assessments should document the uncertainties, the assumptions made, and the effect of these on the final risk estimate.
6. Risk increases with increasing volume of commodity imported.
7. The risk assessment should be amenable to updating when additional information becomes available.
Release assessment consists of describing the biological pathway(s) necessary for an importation activity to «release» (that is, introduce) pathogenic agents into a particular environment, and estimating the probability of that complete process occurring, either qualitatively (in words) or quantitatively (as a numerical estimate). The release assessment describes the probability of the «release» of each of the potential hazards (the pathogenic agents) under each specified set of conditions with respect to amounts and timing, and how these might change as a result of various actions, events or measures. Examples of the kind of inputs that may be required in the release assessment are:
a) Biological factors
- species, age and breed of animals
- agent predilection sites
- vaccination, testing, treatment and quarantine.
b) Country factors
- incidence/prevalence
- evaluation of veterinary services, surveillance and control programmes and
zoning systems of the exporting country.
c) Commodity factors
- quantity of commodity to be imported
- ease of contamination
- effect of processing
- effect of storage and transport.
If the release assessment demonstrates no significant risk, the risk assessment concludes.
Exposure assessment consists of describing the biological pathway(s) necessary for exposure of animals and humans in the importing country to the hazards (in this case the pathogenic agents) released from a given risk source, and estimating the probability of the exposure(s) occurring, either qualitatively (in words) or quantitatively (as a numerical estimate).
The probability of exposure to the identified hazards is estimated for specified exposure conditions with respect to amounts, timing, frequency, duration of exposure, routes of exposure (e.g. ingestion, inhalation, or insect bite), and the number, species and other characteristics of the animal and human populations exposed. Examples of the kind of inputs that may be required in the exposure assessment are:
a) Biological factors
- properties of the agent.
b) Country factors
- presence of potential vectors
- human and animal demographics
- customs and cultural practices
- geographical and environmental characteristics.
c) Commodity factors
- quantity of commodity to be imported
- intended use of the imported animals or products
- disposal practices.
If the exposure assessment demonstrates no significant risk, the risk assessment may conclude at this step.
Consequence assessment consists of describing the relationship between specified exposures to a biological agent and the consequences of those exposures. A causal process must exist by which exposures produce adverse health or environmental consequences, which may in turn lead to socio-economic consequences. The consequence assessment describes the potential consequences of a given exposure and estimates the probability of them occurring. This estimate may be either qualitative (in words) or quantitative (a numerical estimate). Examples of consequences include:
a) Direct consequences
- animal infection, disease, and production losses
- public health consequences.
b) Indirect consequences
- surveillance and control costs
- compensation costs
- potential trade losses
- adverse consequences to the environment.
Risk estimation consists of integrating the results from the release assessment, exposure assessment and consequence assessment to produce overall measures of risks associated with the hazards identified at the outset. Thus risk estimation takes into account the whole of the risk pathway from hazard identified to unwanted outcome.
For a quantitative assessment, the final outputs may include:
Risk management is the process of deciding upon and implementing measures to achieve the Member Country's appropriate level of protection, whilst at the same time ensuring that negative effects on trade are minimized. The objective is to manage risk appropriately to ensure that a balance is achieved between a country's desire to minimize the likelihood or frequency of disease incursions and their consequences and its desire to import goods and fulfil its obligations under international trade agreements.
The international standards of the OIE are the preferred choice of sanitary measures for risk management. The application of these sanitary measures should be in accordance with the intentions in the standards.
1. Risk evaluation - the process of comparing the risk estimated in the risk assessment with the Member Country's appropriate level of protection.
2. Option evaluation - the process of identifying, evaluating the efficacy and feasibility of, and selecting measures in order to reduce the risk associated with an importation in line with the Member Country's appropriate level of protection. The efficacy is the degree to which an option reduces the likelihood and/or magnitude of adverse biological and economic consequences. Evaluating the efficacy of the options selected is an iterative process that involves their incorporation into the risk assessment and then comparing the resulting level of risk with that considered acceptable. The evaluation for feasibility normally focuses on technical, operational and economic factors affecting the implementation of the risk management options.
3. Implementation - the process of following through with the risk management decision and ensuring that the risk management measures are in place.
4. Monitoring and review - the ongoing process by which the risk management measures are continuously audited to ensure that they are achieving the results intended.
1. Risk communication is the process by which information and opinions regarding hazards and risks are gathered from potentially affected and interested parties during a risk analysis, and by which the results of the risk assessment and proposed risk management measures are communicated to the decision-makers and interested parties in the importing and exporting countries. It is a multidimensional and iterative process and should ideally begin at the start of the risk analysis process and continue throughout.
2. A risk communication strategy should be put in place at the start of each risk analysis.
3. The communication of risk should be an open, interactive, iterative and transparent exchange of information that may continue after the decision on importation.
4. The principal participants in risk communication include the authorities in the exporting country and other stakeholders such as domestic and foreign industry groups, domestic livestock producers and consumer groups.
5. The assumptions and uncertainty in the model, model inputs and the risk estimates of the risk assessment should be communicated.
6. Peer review is a component of risk communication in order to obtain scientific critique and to ensure that the data, information, methods and assumptions are the best available.
For the purposes of the Code, every Member Country shall recognize the right of another Member Country to undertake, or request it to undertake, an evaluation of its veterinary services where reasons exist concerning trade in animals, animal products, animal genetic material, biological products and animal feedstuffs between the two countries.
Reasons are deemed to exist where the initiating Member Country is an actual or a prospective importer or exporter of animals, animal products, animal genetic material, biological products or animal feedstuffs and where the evaluation is to be a component of a risk assessment process which is to be used to determine or review sanitary/animal health measures which apply to such trade.
Any evaluation should be conducted having regard to OIE guidelines.
The evaluation of veterinary services shall be conducted by Member Countries on a bilateral basis. The two countries concerned should consult mutually on the evaluation criteria, the information required and on the outcome of the evaluation.
A Member Country which intends to conduct an evaluation of another Member Country's veterinary services shall give them notice in writing. This notice should define the purpose of the evaluation and details of the information required.
The choice of criteria on which evaluation is conducted should be appropriate to the circumstances applying to the countries concerned. Criteria should be relevant to the type of the trade involved, the animal production systems in the respective countries, the difference in animal health status and veterinary public health standards between the countries and other factors which relate to the overall risk assessment.
On receipt of a formal request for information to enable an evaluation of its veterinary services by another Member Country, and following bilateral agreement of the evaluation criteria, a Member Country should provide expeditiously to the other country meaningful and accurate information and data of the type requested.
The outcome of an evaluation conducted by a Member Country should be provided in writing as soon as possible, and in any case within four months of receipt of the relevant information, to the Member Country which has undergone the evaluation. The evaluation report should detail any findings which affect trade prospects. The Member Country that conducts the evaluation should clarify in detail any points of the evaluation on request.
A Member Country involved in the international trade of live animals, animal products, animal genetic material, biological products or animal feedstuffs should generate and maintain current information on its veterinary services having regard to OIE guidelines.
A Member Country can request the Director General of the OIE to arrange for an expert or experts to assist in the self-evaluation of its veterinary services.
In the event of a dispute between two Member Countries over the appropriate evaluation criteria or the outcome of the evaluation of the veterinary services, the matter should be dealt with having regard to procedures set out in Article 1.4.1.8.
It has been customary in the past, when evaluating the animal disease situation in a country with a view to exports of animals and/or animal products, to judge the country as a whole. If an infectious disease existed somewhere within a country's borders, or if its presence was suspected, the whole country was considered infected. As a policy of risk avoidance rather than risk assessment was usually followed, this frequently resulted in considerable, although from the point of view of animal health not always necessary, restrictions in international trade. Climatological and geographical barriers are more effective in containing animal diseases than are frontiers, and factors such as population density, vector distribution, animal movements and management practices are of paramount importance in determining the distribution of diseases, both nationally and internationally. Recognition of the biological basis of variations in the presence or extent of disease is a first step, leading to the application of the concepts of zoning and regionalization to animal health regulations for international trade. Application of the principles of zoning in international trade requires the establishment of internationally accepted standards with regard to terminology and such aspects as zonal boundaries, legal competence, duration of disease free periods, standards of surveillance, use of buffer zones, quarantine procedures, and other aspects of regulatory veterinary medicine.
A zone is a part of a country established for disease control purposes.
A region is a number of countries or parts of contiguous countries, which is established for disease control purposes.
In a country wishing to set up a system of zoning for controlling an animal disease, the disease must be notifiable.
The requirements for different types of zones vary with the disease for which they are established. Size, location and delineation will depend on the disease, its method of spread and its status in the country. Separate conditions will be developed for each disease for which zoning and regionalization are considered appropriate. The extent of zones and their limits should be established by the Veterinary Administration and enforced by national legislation. They should be clearly delineated by natural, artificial or legal boundaries, which must be effective.
Constant supervision to prevent livestock from crossing the boundaries is essential. In addition, it may be necessary to control movement of animal products, animal genetic material, biological products, pathological material and animal feedstuffs within and between zones.
Countries wishing to set up a system of zoning must have an effective veterinary organization and infrastructure. There must be adequate administrative structures, provided with legal and financial resources to give adequate support for the development of the different actions required.
The Veterinary Service must have the necessary resources at its disposal and must be able to supervise the boundaries, maintain clinical and epidemiological surveillance and carry out the necessary diagnostic tests. There must be prompt reporting of outbreaks of disease to the OIE, and documented evidence must be provided that an effective system of disease control and surveillance is in operation, at least in the different zones if not in the whole of the country.
The following types of zones are recognized:
1. A disease free zone without vaccination can be established in a country where the infection is still present. In the disease free zone, there must be official knowledge of the location of all establishments. Suspected outbreaks of the disease must be investigated immediately by the Veterinary Authority. Outbreaks must be reported to the OIE. If necessary, the disease free zone is separated from the rest of the country and from infected neighbouring countries by a surveillance zone. Importation of livestock from other parts of the country or from countries where the disease still exists into the disease free zone must take place under strict controls established by the Veterinary Administration.
The disease free zone should not be dependent on importation of animals or animal products from infected zones or countries that could introduce the disease.
2. A surveillance zone must have certain minimum dimensions, depending on the geographical and climatic conditions and the nature of the disease. Vaccination is not permitted. Animal movements must be controlled. The surveillance zone must have an advanced degree of disease control and surveillance.
Suspected outbreaks of the disease must be investigated immediately and, if confirmed, eliminated. Accordingly, it may be necessary to modify the boundaries of the zone.
Importation of susceptible livestock into the surveillance zone from parts of the country or from other countries where the disease exists can only take place under suitable controls established by the Veterinary Administration. The animals must be unvaccinated. Freedom from infection should be confirmed by appropriate tests.
3. A disease free zone with vaccination will only be applicable for certain diseases.
Such a zone can be developed in a country that is free from the disease, but where it is considered prudent to apply vaccination because of a threat from outside, or in an already infected country. Claims of freedom from disease will have to be supported by convincing evidence of intensive and effective disease surveillance. Suspected outbreaks must be investigated immediately. Establishment of a disease free zone with vaccination requires that the boundary around the zone must have been operative some time before the zone is officially established. Importation of susceptible livestock from other parts of the country, or from other countries where the disease exists, into the disease free zone must take place under suitable controls established by the Veterinary Administration. The animals must be tested for the absence of the infection, and then vaccinated and marked with a recognizable permanent mark before entering the zone.
The disease free zone should not be dependent on importation of animals or animal products from infected zones or countries that could introduce the disease unless adequate import conditions are applied.
4. A buffer zone is a zone where the animals are systematically vaccinated for the protection of a disease free country or zone.
A buffer zone must have certain minimum dimensions, depending on the geographical and climatic conditions and the nature of the disease. Vaccinated animals must be recognizable by a specific permanent mark. The vaccines used must meet OIE standards. Animal movements must be controlled. The buffer zone must have an advanced degree of disease control and surveillance. Suspected outbreaks must be investigated immediately and, if confirmed, be eliminated. Importation of susceptible livestock from other parts of the country or from other countries where the disease exists, must take place under suitable controls established by the Veterinary Administration. The animals must have been vaccinated before entering the buffer zone.
5. An infected zone is a zone where the disease is present, in an otherwise disease free country. A surveillance zone will separate the infected zone from the remainder of the country. Movement of susceptible livestock out of the infected zone into the disease free parts of the country must be strictly controlled. Four alternatives can be considered:
a) no live animals may leave the zone, or
b) animals can be moved by mechanical transport to a special abattoir located in the surveillance zone for immediate slaughter, or
c) exceptionally, live animals can enter the surveillance zone under suitable controls established by the Veterinary Administration. Freedom from infection of these animals must be confirmed by appropriate tests before entering the zone, or
d) live animals can leave the infected zone if the epidemiological conditions are such that disease transmission cannot occur.
Countries wishing to obtain recognition of a disease free zone must demonstrate that they have a reliable system of disease control and surveillance, that the disease is notifiable, and that they have an effective veterinary organization. The Veterinary Service must accurately specify the delineation of the zone, describe how the boundaries are controlled, and supply further information about additional measures that have been taken, covering such aspects as control of animal movements, and quarantine.
Countries which fulfil these conditions can submit the documented evidence of their status to the OIE with a request to be included in the relevant OIE list.
Adjacent countries or parts of countries which have the same animal health status and similar disease controls can be treated as a region. The region must be clearly delineated by natural, artificial or legal boundaries which must be effective. The region must have a common control policy for the specific disease. There must be a uniform and effective system of epidemiological surveillance throughout the region and an official animal health agreement between the countries involved.
The ability of the veterinary services to substantiate elements of their animal disease status reports by surveillance data, results of monitoring programmes and details of disease history is highly relevant to the procedures of risk analysis. However, if the risk assessment conducted on a commodity demonstrates an insignificant risk, this may not be necessary.
The science of epidemiology provides the foundation for surveillance and monitoring. A national epidemiological system should incorporate agent surveillance and/or monitoring, description of host population characteristics, and environmental assessment. An effective veterinary infrastructure is necessary to support this epidemiological system.
Surveillance means the continuous investigation of a given population to detect the occurrence of disease for control purposes, which may involve testing of a part of the population.
Monitoring constitutes on-going programmes directed at the detection of changes in the prevalence of disease in a given population and in its environment.
The following Articles represent a standardized approach to meet the demand for scientifically based import trade requirements.
Agent surveillance and monitoring may involve the clinical or pathological examination of animals, the identification of pathogens, and the detection of immunological or other evidence of previous exposure of animals to pathogens.
Investigation of the suspicion of cases of animal disease is one of the most important means of agent surveillance. Investigations may focus on exotic or new and emerging diseases within the country.
A complete epidemiological system may also require the screening of animals for List A and List B diseases having a major economic impact on trade in animals and animal products, as appropriate to the disease status of the country.
Depending on the diseases present and the priorities with regard to export, components of agent screening may include the following active and passive surveillance methods:
a) scientifically based surveys;
b) routine sampling and testing of animals on the farm, at market or at slaughter;
c) an organized sentinel programme, sampling animals, herds, flocks, or vectors, and/or collecting diagnostic results from veterinary practices;
d) the banking of biological specimens for retrospective studies; and
e) analysis of veterinary diagnostic laboratory records.
Description of host population characteristics concentrates on the factors in the national animal population which may influence or be associated with disease occurrence. These host factors may include:
a) intrinsic factors such as genetics, animal demographics (age, sex, breed distribution) and physiological state (immature, sexually mature but un-bred, gestating, geriatric); and
b) extrinsic factors such as marketing and movement patterns, domestic/wild animal interactions, animal use (draft, meat production, milk or egg production, pets) and management factors (husbandry system, preventive medical practices).
The linkage of demographic data to agent surveillance data is critical for predicting the potential spread of diseases or identifying optimal control measures.
Data on environmental assessment include physical factors, biological environmental factors, and economic and structural characteristics of ancillary industries.
Some examples of these data are as follows:
Air and water quality monitoring, topographical and soil distribution maps, and meteorological data are routinely collected in many countries by a variety of government agencies. Additional data may be available from university researchers or private industry.
Vector population distributions may be available from specialists on invertebrates. Vector competence data describes the ability of specific vectors to serve as biological vectors for specific diseases.
Data on feed and slaughter industries, on the biologics and pharmaceutical industries, and on marketing and distribution patterns help define the intervention options available in each country.
This information allows estimation of trends for the future, geographic shifts in animal production and processing, and more accurate assessment of disease risk and characterization and delineation of zones. Much of the required data may be obtained through governmental or non-governmental sources.
