The Canadian Food Inspection Agency says it is aware of another suspected case of a highly infectious salmon virus in British Columbia, but it will take weeks to verify the findings.

The agency confirmed this week that a laboratory at the University of Prince Edward Island suspects infectious salmon anemia in a coho salmon from British Columbia. A Department of Fisheries and Oceans lab in Moncton, N.B. is now validating the results.

Observers of the nearly two-decade-long debate between salmon farmers and their critics say if a potentially devastating European strain of the disease is confirmed, the findings could provide the "smoking gun" environmentalists have long been looking for to turn the argument in their favour.

"Presuming that they (the samples being tested) are the same variant of the virus that's found elsewhere in the world, then I think that would cause serious problems to our salmon farming industry," said Peter Robson, author of the book "Salmon Farming: The Whole Story."

"It would mean that we've imported a disease from another country for the first time as far as salmon farming goes."

The announcement comes at a critical time in B.C.

The Cohen Commission, which is studying what caused the collapse of the Fraser River sockeye run in 2009, began hearing final arguments Friday, but announced it would add two days of hearings next month devoted solely to the virus.

Almost two weeks ago, Rick Routledge, a Simon Fraser University fish-population statistician, announced ISA had also been found in two sockeye smolts from B.C's Central Coast, a finding federal officials are trying to verify.

According to the CFIA website, the virus can kill up to 90 per cent of infected fish, although some strains do not cause high mortality rates.

The European strain of the disease was linked to an outbreak on fish farms in Chile a few years ago, and the industry lost 70 per cent of its stocks.

But it's not clear how the disease would affect wild or farmed fish stocks in British Columbia.

While the virus' causes are unknown, ISA is not a risk to human health, says the agency, which also notes a vaccine is available to prevent the disease but no treatment is available for fish already infected.

The virus found in the Harrison Lake coho, in B.C.'s Fraser Valley, was of the European strain, said a report by the Atlantic veterinary college at the University of PEI.

Routledge previously announced that the findings from the Central Coast were of the same strain that wiped out farmed salmon stocks in Chile.

Biologist and fish farm critic Alexandra Morton said she sent the Harrison Lake samples to the veterinary college after collecting dead salmon from the area on Oct. 12.

Morton said she received results of those tests this week, confirming low levels of the European virus in the heart of a coho.

"There's really no winning this for me anymore because the damage has been done," said Morton. "This is just exactly the kind of thing we did not want to have happen -- an exotic virus coming in. So from here on in, it's just trying to reduce the damage."

Pathologist and microbiologist Fred Kibenge, who conducted the tests, was unavailable for comment. Instead, the university directed media questions to the food inspection agency.

The source of the disease remains unknown. Critics of salmon farms blame the industry, but the industry vigorously contests the allegations.

Mary Ellen Walling, executive director of the B.C. Salmon Farmers Association, said ISA's presence in British Columbia has not yet been confirmed and it has not appeared on member farms even though more than 5,000 samples have been tested.

"Our farmers have offered to provide further samples for testing by CFIA and are advocating for more sampling and testing of our region's wild fish," Walling said in an emailed statement.

Walling said Kibenge's lab indicated positives in only three of 20 samples, and only one of the three tested positive for the European strain.

She said Kibenge has also qualified his findings, and the results do not mean the virus is present in the area where the subject fish came from.

To confirm the results, the virus has to be isolated, she said.

Morton, though, said she suspects the virus originated with the industry, adding the disease proliferates in crowded conditions.

She said the virus tends to appear where Atlantic salmon are raised.

"What we need desperately is a lab in British Columbia who will test these fish, test the samples fresh because we need to culture the actual virus," said Morton.

Robson said clear test results showing the virus is present are now critical.

For years, critics have been blaming fish farms for declining stocks, but haven't been able to prove any permanent damage, he said.

He said confirmation of the virus could be "one of the smoking guns in the salmon farming debate" and "may be a big problem."

"Is it a game changer? It would be a game changer if it was sourced to aquaculture," said Tony Farrell, a professor in the University of British Columbia's department of zoology.

But Farrell said scientists need to confirm where the virus originated, adding people "are jumping to conclusions as to the source of it."

"I think if ISA is now around, we need to be worried about ISA," he said.

Daniel Pauly, a professor and director of UBC's fisheries centre, has been watching the debate since he came to B.C. in 1994 and said a piece of the province's culture is at stake.

"What is at stake is actually wild salmon," he said. "In Europe there is almost no wild salmon left. So there is not so much of a risk. In B.C., the wild salmon are huge and iconic in the province."

Pauly said he suspects the virus has come from the industry because millions of Atlantic salmon eggs have been imported to British Columbia.

The emergence of ISA, he said, has been inevitable, even though some have argued the probability was low, said Pauly.

He called for a contingency plan to be developed.

According to B.C.'s Ministry of Environment, the province's salmon farming industry is the fourth largest producer of farmed salmon in the world, and in 2009, 18 companies operated on 131 sites.