Health Risk Analysis in Wild Animal Translocations

Introduction to Risk Health Analysis


This document gives step-by-step procedural guidelines to analyze health and related risks associated with movement of wild animals from one geographic location to another. While the primary purpose of this document is to provide guidelines for health risk analysis by importing nations in the international movement of wild animals, the procedure outlined can be applied equally well to all wild animal translocations.


The approach taken follows the OIE International Health Code, Section 1.3, and also draws heavily on the Risk Assessment Frameworks documentation of the Ontario Ministry of Agriculture, Food and Rural Affairs. Technical terms associated with risk analysis used in this document are defined in the OIE International Health Code, Section 1.4.

This document was prepared by the Canadian Cooperative Wildlife Health Centre and the Working Group on Wildlife Diseases of the OIE.


Wild animals are moved from place to place for many different reasons. Most often, they are captured in the wild, transported, held in quarantine, and released again into the wild for conservation or wildlife management purposes. There are potential health risks associated with all such movements of wild animals. The principal risks are:

  1. That the animals will carry new diseases into the destination ecosystem that will cause harm to the destination ecosystem.
  2. That the animals being moved will encounter new diseases in the destination ecosystem and will be harmed by these new diseases.

Health risk analysis must be carried out prior to the translocation of wild animals in order to determine a) whether or not such risks exist, and b) the magnitude of the potential consequences, to the economy and ecology of the destination area and to the success of the translocation program. The results of such risk analysis can then be incorporated into the final decision whether or not to proceed with the translocation. If the decision is to proceed but significant risks have been identified, the risk analysis can guide efforts to reduce risk.

Risk Analysis Process

Health risk analysis is a rigorous application of common sense to determining whether or not there are important health-related risks associated with a proposed activity, such as animal translocation. Risk analysis can be qualitative, in which risk is estimated as being negligible, low, medium or high, or it can be quantitative, in which mathematical models are used to give numerical estimates of the probability of a negative outcome and the economic, ecological and social harm that would occur as a result.

Wild animal health risk analysis usually will result in a qualitative assessment of risk. This is because, most often, there is not enough reliable numerical information about wild animals and their diseases to support a reliable quantitative assessment of risk.

The Risk Analysis Report

The product of a risk analysis is a written report that documents all steps followed, all of the information considered and the way that information was evaluated.

Basic Steps in Health Risk Analysis in Wild Animal Translocations
  1. Translocation Plan:
    A complete, detailed description of the translocation is made. This clearly defines the activity for which health risks are to be analyzed.
  2. Hazard Identification and Selection for Assessment:
    A complete, inclusive list of all potential health and related hazards is made. This step requires gathering of much information. If sufficient information is not available, this must be recognized and the risk analysis halted (see "Information Requirements" below).
    From the complete list of potential hazards, the hazards that appear most important are selected for detailed consideration. Often, only a small number of hazards can be fully assessed. These must be chosen with care to represent the greatest potential for a harmful outcome.
  3. Risk Assessment:
    Risk is assessed for each major hazard selected. Risk has two parts:
    • The probability that the health hazard will occur in the translocation program.
    • The magnitude of the negative consequences if it does occur.
  4. Overall Risk Assessment and Statement of Uncertainty:
    An overall assessment is made by combining the results of the assessments of each of the major hazards assessed individually.
    In every risk assessment, absence of certain information limits the precision of the assessment. A statement outlining important areas of uncertainty that have affected the risk assessment is written to give a complete picture of the strengths and limitations of the risk assessment.
  5. Associated Hazards and Risks:
    Hazards that may not be directly related to health issues often become apparent during health risk analysis. A statement identifying these is written and included in the risk assessment.
  6. Risk Reduction:
    During a risk analysis, it may become evident that some of the risks identified could be reduced by changing procedures to be used in the translocation program. A statement about ways in which risks may be reduced is included in the risk assessment.
Information Requirements

Many different kinds of information are required for risk analysis: species and populations of animals, disease-causing agents and their mechanisms of transmission and spread, transportation and quarantine facilities and procedures, and general information about the source and destination ecosystems, including their human economies and cultures. If sufficient information is not available, it is not possible to carry out an analysis of health risks.

Decision Making

Decisions whether or not to proceed with wild animal translocations may be determined by the results of health risk analysis, but they also may be influenced by a variety of other factors. Risk analysis informs decision makers regarding health risks and provides them with options to reduce risk if it is decided to proceed with the translocation.

Objectivity, Subjectivity, and Transparency

Health risk analysis must be as objective as possible. It should be based on all of the available, relevant information and firmly on science. However, it is not possible to conduct a health risk analysis that is entirely free of subjective judgement. It is possible and essential, however, to identify clearly when a subjective judgement is used within a risk analysis. The basis for such judgements should be clearly stated so that there can be no confusion by the reader of the risk analysis report regarding which elements of the analysis are based on science and which are based on subjective assessments. Thus, health risk analysis must be transparent. The reader of a health risk analysis report must be informed of all of the information that was available to the analysts, must be shown how the information was evaluated and how risk assessments were derived, must be informed of information that was not used or that was ignored, and must be informed of the uncertainties associated with the risk analysis.

The OIE International Animal Health Code urges that transparency is "essential because data are often uncertain or incomplete and, without full documentation, the distinction between facts and the analyst's value judgements may blur." Chapter

Detailed Guideline for Carrying Out Health Risk Analysis