When it comes to ISAV and SAV the main source of infection has mainly been other farmed fish, and focus on susceptible marine fish has therefore been scarce. However new knowledge and new problems have lately made marine fish reservoirs more interesting.
Low pathogenic strains of ISAV (HPRO) have been detected in high prevalence of both wild and farmed salmonids, and it has been hypothesised that these strains may transition into high pathogenic variants of the virus. Several reports conclude that knowledge on possible marine reservoirs for both high and low virulent ISAV is needed.
Lately a new variant of SAV (marine SAV-2) have caused major problems in Norwegian salmon farming. Different isolates of marine SAV-2 are more heterogenic than SAV-3 and marine reservoirs are therefore more likely.
Fish from part 1 of the project will be tested with real time RT-PCR for ISAV / SAV, and any detection of virus will be further characterised with both virological and epidemiological methods. We are lucky to have a very good project group with extensive knowledge on many research fields necessary for interpreting any findings of ISAV or SAV in the wild fish. Any detections of virus will lead to many new questions that need to be addressed in further research.
Testing of the already existing material provides a low cost opportunity as a first step into the field of marine reservoirs for ISAV and SAV.
Institute of Marine Research, Norway: Øivind Bergh, Nina Sandlund, Jens Christian Holst
Aqua Veterinary Services, Ireland: Dr. Marian McLoughlin