Aquatic Animal Health Code
Criteria for listing species as susceptible to infection with a specific pathogen
The decision to list a species as susceptible should be based on a finding that the evidence is definite. However, possible susceptibility of a species is also important information and this should also be included in Section 2.2.1. entitled «Susceptible host species» of the relevant disease-specific chapter of the Aquatic Manual.
Stage 1: criteria to determine whether the route of transmission is consistent with natural pathways for the infection
The evidence should be classified as transmission through:
non-invasive experimental procedures; includes cohabitation with infected hosts, infection by immersion or ingestion; or
invasive experimental procedure; includes injection, exposure to unnaturally high loads of pathogen, or exposure to stressors (e.g. temperature) not encountered in the host's natural or culture environment.
Consideration needs to be given to whether experimental procedures (e.g. inoculation, infectivity load) mimic natural pathways for disease transmission. Consideration should also be given to environmental factors as these may affect host resistance or transmission of the pathogen.
Stage 2: criteria to determine whether the pathogenic agent has been adequately identified
The pathogenic agent should be identified and confirmed in accordance with the methods described in Section 7 (corroborative diagnostic criteria) of the relevant disease chapter in the Aquatic Manual, or other methods that have been demonstrated to be equivalent.
Stage 3: criteria to determine whether the evidence indicates that presence of the pathogenic agent constitutes an infection
clinical or pathological changes are associated with the infection;
the specific location of the pathogen corresponds with the expected target tissues.
Outcomes of the assessment
The decision to list a species as susceptible should be based on a finding of definite evidence. Evidence should be provided for the following:
there is evidence of infection with the pathogenic agent in the suspect host species in accordance with criteria A to D in Article 1.5.6.. Evidence to support criterion A alone is sufficient to determine infection. In the absence of evidence to meet criterion A, satisfying at least two of criteria B, C or D would be required to determine infection.
Species for which there is incomplete
evidence for susceptibility
However, where there is insufficient evidence to demonstrate susceptibility through the approach described in Article 1.5.3. because transmission does not mimic natural pathways of infection, or the identity of the pathogenic agent has not been confirmed, or infection is only partially supported, information will be included in the relevant disease-specific chapter in the Aquatic Manual.
If there is insufficient evidence to demonstrate susceptibility of a species, the Competent Authority should assess the risk of spread of the pathogen under consideration, in accordance with the recommendations in Chapter 2.1., prior to the implementation of import health measures.
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