I'll start, and then I'll pass it over to Dr. Fleming for an international perspective.
ISA first appeared in Canadian waters in the mid-to-late nineties in New Brunswick and resulted in losses of enormous numbers of salmon. Many farmed salmon had to be destroyed. This disease is basically anemia—red blood cells are reduced in abundance, and oxygen can't get to various organs in the fish. It's a highly infectious disease. Whenever you hold organisms of a farmed or wild nature in a very dense situation, the likelihood of disease increases dramatically. This particular disease is very infectious, very volatile. That is one of the reasons that entire sea cages are destroyed as a consequence.
ISA has been documented in some wild salmon. I know the Magaguadavic River in New Brunswick is one area where wild Atlantic salmon have been found to have this virus. Now, it isn't a natural virus, and one cannot say whether the virus originated from a farm or not. Some of these diseases, if they are transmitted to wild populations—particularly when wild populations are depleted and things like sea lice are carriers—pose a considerable risk to these depleted populations. This is one of the things the report attempts to point out.
There was a good example in Norway that I'll ask Dr. Fleming to address.