The Vancouver Sun reports that Grieg Seafood put its Ahlstrom Point farm, near Sechelt, into voluntary quarantine last week after routine tests by Fisheries and Oceans found a low positive result for IHN in the company's coho salmon.
"As is typical in these situations, the CFIA advised us they are now formalising our voluntary isolation with an official quarantine," said Stewart Hawthorn, spokesman for Grieg Seafood.
The company agrees with the cautious approach and is waiting to see whether the test is confirmed before deciding on the next step, Mr Hawthorn said.
"Right now, they are taking more samples because the result they got was a very, very weak result," he said.
However, even if the virus is confirmed, it is unlikely the fish will have to be destroyed as they are not showing any sign of illness, Mr Hawthorn said.
IHN is carried by wild Pacific salmon, including coho, but the fish have developed a natural resistance.
"We are not expecting these fish to get sick," Mr Hawthorn said.
However, the virus is lethal for Atlantic salmon - the species raised by most salmon farmers on the west coast, and 570,000 Atlantic salmon from Mainstream Canada's Dixon Bay farm in Clayoquot Sound were destroyed this week after the IHN virus was confirmed.