According to a 2014 summary of facts from the environmental group Ecojustice, PRV was discovered in 2010 and is thought to cause a severe infectious fish disease known as heart and skeletal muscle inflammation.

Ecojustice said the disease was first observed in farmed Atlantic salmon in a single fish farm in Norway in 1999. At the time the summary was released, it said 419 farms were infected with the disease in Norway.

Gilles Olivier, who co-chaired the review for Fisheries and Oceans Canada, said knowledge gaps about the virus include how long it survives and its concentration in the water.

While the virus is causing mortality in fish in Norway, it's not killing British Columbia's sockeye or Atlantic salmon even when it is injected in high doses, Olivier said in a conference call with reporters on Thursday.

"It doesn't seem to have the same effect in our Atlantic salmon here in B.C. than it does in Norway,” he said.

"There is no evidence to suggest that PRV causes disease and mortality in sockeye salmon.”