Aquatic Animal Health Code
Import risk analysis
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 aquatic animals, aquatic animal products, aquatic animal genetic material, feedstuffs, biological products and pathological material. The principles and methods are the same whether the commodities are derived from aquatic and/or terrestrial animal sources. 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 chapter provides recommendations and principles for conducting transparent, objective and defensible risk analyses for international trade. However, it cannot provide details on the means by which a risk analysis is carried out as the purpose of the Aquatic Code is simply to outline the necessary basic steps. The components of risk analysis are hazard identification, risk assessment, risk management and risk communication (Figure 1).
Fig. 1. The four components of risk analysis
The risk assessment is the component of the analysis that estimates the risks associated with a hazard. Risk assessments may be qualitative or quantitative. For many diseases, particularly for those diseases listed in the Aquatic 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 on aquatic animals and aquatic animal products usually needs to take into consideration the results of an evaluation of the Aquatic Animal Health Services, zoning and compartmentalisation, and surveillance systems that are in place for monitoring aquatic animal health in the exporting country. These are described in separate chapters in the Aquatic Code.
The 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 hazard is already present in the importing country, and whether it is a listed 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 categorisation step, identifying biological agents dichotomously as hazards or not hazards. The risk assessment should be concluded if hazard identification fails to identify hazards associated with the importation.
The evaluation of the Aquatic Animal Health Services, surveillance and control programmes, and zoning and compartmentalisation systems are important inputs for assessing the likelihood of hazards being present in the aquatic animal population of the exporting country.
Principles of risk assessment
Risk assessment should be flexible in order to deal with the complexity of real-life situations. No single method is applicable in all cases. Risk assessment should be able to accommodate the variety of aquatic animalcommodities, 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.
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.
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.
The risk assessment should be amenable to updating when additional information becomes available.
Risk assessment steps
Entry assessment consists of describing the biological pathway(s) necessary for an importation activity to introduce a pathogenic agent into a particular environment, and estimating the probability of that complete process occurring, either qualitatively (in words) or quantitatively (as a numerical estimate). The entry assessment describes the probability of the entry of each of the hazards (the pathogenic agents) or 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 entry assessment are:
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) from a given risk source, and estimating the probability of these 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, 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:
Properties of the agent (e.g. virulence, pathogenicity and survival parameters)
Genotype of host.
Presence of potential vectors or intermediate hosts
Aquatic animal demographics (e.g. presence of known susceptible and carrier species, distribution)
Human and terrestrial animal demographics (e.g. possibility of scavengers, presence of piscivorous birds)
Customs and cultural practices
Geographical and environmental characteristics (e.g. hydrographic data, temperature ranges, water courses).
Consequence assessment consists of describing the relationship between specified exposures to a biological agent and the consequences of those exposures. A causal process should 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:
Risk estimation consists of integrating the results of the entry 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:
Probability distributions, confidence intervals, and other means for expressing the uncertainties in these estimates
Portrayal of the variance of all model inputs
A sensitivity analysis to rank the inputs as to their contribution to the variance of the risk estimation output
Analysis of the dependence and correlation between model inputs.
Principles of risk management
Risk management is the process of deciding upon and implementing measures to address the risks identified in the risk assessment, whilst at the same time ensuring that negative effects on trade are minimised. The objective is to manage risk appropriately to ensure that a balance is achieved between a country's desire to minimise the likelihood or frequency of disease incursions and their consequences and its desire to import commodities 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 of the standards.
Risk management components
Option evaluation - the process of identifying, evaluating the efficacy and feasibility of, and selecting measures to reduce the risk associated with an importation. The efficacy is the degree to which an option reduces the likelihood or magnitude of adverse health 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.
Monitoring and review - the ongoing process by which the risk management measures are continuously audited to ensure that they are achieving the results intended.
Principles of risk communication
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.
The communication of risk should be an open, interactive, iterative and transparent exchange of information that may continue after the decision on importation.
The principal participants in risk communication include the authorities in the exporting country and other stakeholders such as domestic aquaculturists, recreational and commercial fishermen, conservation and wildlife groups, consumer groups, and domestic and foreign industry groups.
Peer review of risk analyses is an essential component of risk communication in order to obtain a scientific critique and to ensure that the data, information, methods and assumptions are the best available.
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