Susceptibility and immune responses following experimental infection of MHC compatible Atlantic salmon (Salmo salar L.) with different infectious salmon anaemia virus isolates

• Published in: Archives of virology 2005-11, Vol.150 (11), p.2195-2216
• Main Authors: MJAALAND, S, MARKUSSEN, T, SINDRE, H, KJØGLUM, S, DANNEVIG, B. H, LARSEN, S, GRIMHOLT, U
• Format: Article
• Language: English
• Subjects: Anemia; Anemia - diagnosis; Anemia - veterinary; Anemia - virology; Animals; Antibodies; Biological and medical sciences; Fish Diseases - epidemiology; Fish Diseases - mortality; Fish Diseases - virology; Fundamental and applied biological sciences. Psychology; Genes; Genomes; Genotype & phenotype; Glycoproteins; Histopathology; Infections; Influenza; Major Histocompatibility Complex; Microbiology; Miscellaneous; Orthomyxoviridae; Orthomyxoviridae Infections - epidemiology; Orthomyxoviridae Infections - mortality; Orthomyxoviridae Infections - virology; Orthomyxovirus; Proteins; Salmo salar; Salmo salar - immunology; Salmo salar - virology; Salmon; Virology; Virulence; Viruses
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-005-0588-8

Infectious salmon anaemia virus (ISAV) is an aquatic orthomyxovirus causing a multisystemic disease in farmed Atlantic salmon (Salmo salar) where disease development, clinical signs, and histopathology vary to a large extent. Here, an experimental trial was designed to determine the effect of variation in viral genes on virus-host interactions, as measured by disease susceptibility and immune responses. The fish were infected using cohabitant transmission, representing a natural route of infection. Variation caused by host factors was minimized using MHC compatible A. salmon half-siblings as experimental fish. Virus isolates were selected according to HE genotype, as European ISAV isolates can be genotyped according to deletion patterns in their hemagglutinin-esterase (HE) surface glycoprotein, and the course of disease they typically induce, classified as acute versus protracted. The different ISAV isolates induced large variations in death prevalence, ranging from 0-47% in the test-group and 3-75% in the cohabitant fish. The use of MHC compatible experimental fish made it possible to determine the relative contribution of humoral versus cellular response in protection against ISA. Ability to induce a strong proliferative response correlated with survival and virus clearance, while induction of a humoral response was less protective.