The proposed project aims to assess the threat of systemic iridoviruses to farmed and wild freshwater fish and amphibian wildlife in the EU. A major element will be experimental infection trials on a range of important European species of farmed and wild freshwater fish and wild amphibians to provide data needed for the assessment. This will include major farmed food species but also representative farmed ornamental fish species that are increasingly being produced in Europe and have long been speculated to be vectors of systemic iridoviruses. Several species of wild predator fish will be tested including European perch, which are highly susceptible to at least one exotic systemic iridovirus. Representative amphibians species will also be tested because wild populations appears to be seriously affected by systemic iridoviruses. Immunological diagnostic methods for the detection of systemic iridoviruses in tissues of naturally infected species will be developed to facilitate the characterization of the pathology and pathogenesis for each susceptible species and allow rapid diagnosis in the event of a future outbreak in EU. Molecular methods will be developed for the differentiation of systemic iridoviruses and thereby provide the means of differentiating the OIE notifiable and highly virulent isolates from the less potent isolates. Surveillance of disease in EU-produced and imported ornamental fish and pet or wild amphibians will be ducted to gain knowledge of the current presence of systemic iridoviruses and indicate the potential for the aquatic pet trade to be a route of introduction and spread. Applying epidemiological principles, a risk assessment model (RAM) will be developed to assess the potential pathways of spread and likely impact of those viruses showing greatest virulence in the experimental trials. Recommendations will be made to the Commission on future actions needed to prevent further incursion and spread of serious iridoviral diseases in the EU.