Australian Quarantine Review Secretariat Australian Quarantine a shared responsibility

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1 ANIMALS

1.1 The OIE Animal Health Code

Animal health standards are set and maintained by the Office International des Epizooties (OIE). At the time of the publication of the International Animal Health Code (OIE 1992) OIE was still considering import risk analysis and a section on risk analysis has only recently been included in the Code. This appendix is adapted from the Code, including updates published in 1993 and 1994, particularly its Section 1.4 on Risk Analysis (OIE 1994). A prototype code for aquatic animals is available (OIE 1995).

1.2 Import Risk Analysis

The Code's Chapter 1.4.1 on import risk analysis states that 'the principal aim of import risk analysis is to provide importing countries with an objective and defensible method of assessing the risks associated with the importation of animals, animal products, animal genetic material, feedstuffs, biological products and pathological material. The analysis should be transparent in order that the exporting country may be provided with a clear and documented decision on the conditions imposed for importation, or refusal of importation ... Import risk analysis is preferable to a zero risk approach because it provides a more objective decision, and enables Veterinary Administrations to discuss any differences in conclusion which may arise concerning potential risks'.

The Code notes that import risk analysis may involve:
· risk assessment, which may be followed by risk management and risk communication;
· evaluation of veterinary services; and
· zoning and regionalisation of countries.
The Code notes that 'countries requiring to carry out an import risk analysis should design their own methodology for carrying out the exercise ... The analysis should be clearly documented and, if necessary, supported by references to the scientific literature. The information reported to the OIE should be the main source of disease occurrence data for the analysis ... In the event of a decision to refuse the importation of a commodity, or to impose significant constraints on the importation, the importing country should if requested be prepared to justify its decision by providing details of the procedures and results of the import risk analysis exercise to the exporting country' (OIE 1994, pp. 28–28/2).

1.3 Estimation of Risk

The Code states that 'an estimate of the risk associated with the import of a commodity in its usual commercial form is referred to as an unrestricted risk estimate. Because of the multiplicity of disease agents, it may be necessary to carry out multiple risk estimates for any commodity considered for importation ... The unrestricted risk estimate is the product of two probabilities, namely the probability of agent entry and the probability of exposure of susceptible species in the importing country. The probability of agent entry is the probability that at least one animal import unit is infected with the agent' (OIE 1994, p. 28/3–4).

1.4 Probability of Agent Entry

1.4.1 Country factor

For reporting to OIE, individual countries assign each disease into one of several categories of disease prevalence — for example, exceptional, low sporadic, enzootic (endemic) or high. Other countries assess this information in conjunction with an evaluation of the veterinary services of the exporting country, particularly in relation to its monitoring and surveillance systems.

OIE classifies animal diseases that are recognised internationally as being of significant importance to trade as List A diseases. These are diseases that can spread very rapidly and have serious socio-economic or public health consequences. Australia is free of all 15 List A diseases, including:
· African horse sickness (never occurred);
· African swine fever (never occurred);
· bluetongue (eight serotypes of bluetongue virus have been isolated in Australia but are limited to northern, mainly cattle producing areas — clinical disease has not occurred in commercial sheep flocks);
· contagious bovine pleuropneumonia (free since 1973);
· foot-and-mouth disease (free since 1872);
· hog cholera or classical swine fever (free since 1961);
· lumpy skin disease (never occurred);
· Newcastle disease — velogenic and mesogenic types (free since 1932; but lentogenic V4 type was identified in 1966);
· peste des petits ruminants (never occurred);
· Rift Valley fever (never occurred);
· rinderpest (free since 1923);
· sheep pox and goat pox (never occurred);
· swine vesicular disease (never occurred);
· vesicular stomatitis (never occurred); and
· virulent avian influenza or fowl plague (free since June 1995).
OIE also defines a second group of diseases (List B diseases) that are considered to be of socio-economic or public health importance within infected countries and are significant in international trade. Australia is free of a large number of diseases classified as List B diseases. In addition, Australia is free of most OIE List B diseases of aquatic animals, and is also free of many diseases listed by OIE as 'significant' diseases of aquatic animals, as well as a number of other serious but unlisted diseases.
The Food and Agriculture Organization defines a third group of animal diseases that are of socio-economic or sanitary importance at the local level. Details of Australia's status with respect to these and OIE-listed diseases are available in Animal Health in Australia annual reports (e.g. Nunn and Thornber 1994).
In the Code, 'the country factor is an estimate of the prevalence of the disease in the exporting country. For List A diseases and some List B diseases, a calculated prevalence is determined as a product of the number of outbreaks that occurred in the previous 12 months, the average herd or flock size, and the average duration of infection, divided by the number of animals in the population ... In the absence of quantitative data, an assigned prevalence is given to the occurrence of List B diseases as reported to the OIE in the categories of exceptional, low sporadic, enzootic (endemic) and high'.

1.4.2 Commodity factor

The commodity factor is an estimate of the probability of the agent being present in or on the commodity at the time of import, and the persistence or survival rate of the agent. Evaluation of the determinants such as the following, if applicable, provides this probability estimate:

· species, age and breed of animal;
· sensitivity of diagnostic tests;
· agent predilection sites;
· ease of agent contamination;

· pH;
· temperature and duration of heat processing;

· temperature and duration of freezing;
· other processing procedures;
· temperature and duration of storage;
· transit temperature and duration; and
· additives and treatments.

1.4.3 Animal import units

The number of animal import units being imported significantly influences the probability of agent entry. A single animal of any species represents one animal import unit for that species. Animal products should be given a kilogram weight equivalence for one animal import unit.

1.5 Probability Of Exposure in the Importing Country

The probability of exposure is the likelihood that the commodity is exposed to animals or humans in the importing country and that agent transmission, infection, disease, and disease spread occur, combined with the likelihood of these events being detected.

Exposure of a particular commodity to animals and humans in such a way as to result in infection of one or more species may depend on a number of factors including:
· the nature of the agent;
· the intended commodity use and distribution;
· presence of potential vectors;
· calendar period of import;
· primary, secondary and intermediate hosts of the agent;
· nature of the commodity;
· human and animal demographics;
· mode of transmission of the disease;
· customs and cultural practices; and
· animal health legislation and compliance.
The importing country should identify the scenarios that could expose animals or humans to the commodity and associated infecting or contaminating agent or agents of concern.

1.6 Risk Management

Options that exist to reduce risk associated with a particular import include:

· choice of the origin of the commodity;
· restricting the destination;
· pre- and post-shipment quarantine, with or without sentinel animals;
· diagnostic testing with tests of estimated validity parameters;
· vaccination;
· processing, maturation and storage for a specified time and temperature; and
· treatments (e.g. heat treatment for a specified time and temperature, use of veterinary drugs, washing of embryos, fumigation of eggs).
The application of a risk reduction option can reduce either the probability of agent entry or the probability of exposure to susceptible animals, or both in the case where more than one risk reduction option is selected.

1.7 Evaluation of Veterinary Services

For the purposes of the Code, every Member Country shall recognise 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.

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 that relate to the overall risk assessment.

1.8 Zoning and Regionalisation

The Code recognises five types of zones: disease-free without vaccination; surveillance; disease-free with vaccination; buffer and infected.

1.8.1 Disease-free zone without vaccination

A disease-free zone can be established in a country where a disease is still present. Suspected outbreaks of a disease should be immediately investigated. If necessary, the zone should be separated from the rest of the country and from infected neighbouring countries by a surveillance zone. Import from infected areas into the zone can only be undertaken under strict control.

1.8.2 Surveillance zone

A surveillance zone must have certain minimum dimensions. Vaccinations are not permitted and animal movements must be controlled. Import from infected areas into the zone can only be undertaken under strict control. Any outbreaks of disease in the zone must be eliminated.

1.8.3 Disease-free zone with vaccination

A disease-free zone with vaccination is only applicable for certain diseases. Such a zone can be developed in a country that is free of disease, but where it is considered prudent to apply vaccination because of the threat from outside, or in an already infected country. Animals imported into the zone must be tested for the infection, and then vaccinated and marked with a recognisable permanent mark before entering the zone.

1.8.4 Buffer zone

A buffer zone is a zone where the animals are systematically vaccinated for the protection of a disease-free country or zone. Vaccinated animals should have a recognisable permanent mark and there must be strict control over animal movements.

1.8.5 Infected zone

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 rest of the country. Four alternative controls over animal movements from the zone can be considered:

· no live animals may leave the zone;
· animals can be moved by mechanical transport to a special abattoir located in the surveillance zone for immediate slaughter;
· exceptionally, live animals can enter the surveillance zone under controls that include testing for freedom from infection; or
· live animals can leave the infected zone if the epidemiological conditions are such that disease transmission can not occur.

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