Epidemiological analysis ISAV
It is generally accepted within the industry that different strains of ISAV are associated with different pathogenicity in the field and in the laboratory. The apparent, but poorly elucidated, disparity in virulence of different ISAV strains confounds management decisions relating to infected fish. Virulence assessment of ISAV strains performed in the laboratory show differences in mortality rates and onset, with some strains such as the hpr0 apparently posing little threat to the health of the fish, and strains such as the hpr4 strains posing considerable threat to infected fish and fish in which they come in contact. While these studies provide useful information on the relative pathogenicity of particular strains, they are rarely an accurate representation of how the strains affect fish in the field. The best indication of ISAV strain pathogenicity can be found from analysis of field data. However such studies are often hampered by incomplete data sets, and confounding factors such as variables between sites and factors that can influence observed disease at a site outside of the pathogen strain itself. In the present study, the industry is making available for study detailed mortality data for ISAV infected and uninfected fish for two year classes of fish. Analysis of this data and other confounding factors will allow elucidation of the impact of different ISAV strains on fish in the field, helping inform fish health decisions regarding depopulation or eradication and disease control, and leading to intelligent and economical disease management.
2008 - 2008
Atlantic: Gulf of Maine, Scotian Shelf
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