That's been known about for a while.
ISA was found in Cultus socks, and yes at a very high percentage (from what I remember 100%? Haven't read the link yet). I forget the person I talked to, but I discovered it a couple years ago.
That is why I keep saying to people we have probably always had an endemic strain of ISA in BC. It wouldn't make sense for only one or two stocks of fish to have it, if it was indeed passed by salmon farms. No one ever tested for it because no one cared, and the only reason Morton is testing for it now is because she wants another crutch to lean on to remove salmon farms.
What I find curious is that no one has tested Cultus lake in itself for the virus. It has to be coming from somewhere, unless it is the first case of vertical transmission of the virus.
I'm still pretty convinced that this isn't causing sockeye decline. Pacific salmon don't show any infectious symptoms of ISA, even when infected with highly pathogenic strains. This could in theory change (genetic mutation), but chances are that it won't. At this point ISA doesn't cause death in pacific's, and the fact that Morton is finding dead spawning salmon with it DOES NOT mean it is killing them. They could have well been carrying it their whole life. Until she can show a legitimiate study showing disease in Pacific salmon infected with ISA, and death, I'm not convinced of anything she says - just like I'm more convinced we had an endemic strain of ISA rather than one brought by fish farms.