No Immediate Danger from ISA Virus Says Pathologist

By Margaret Bauman

Alaska’s chief fish pathologist said Dec. 7 that the state’s wild Pacific salmon stocks are in no immediate danger from the infectious salmon anemia virus, a pathogen linked to fish farming that has killed millions of salmon in Chile and Europe.

“I think science will prevail and at some point we will get some answers, but I don’t think our wild stocks are in immediate jeopardy,” said Ted Meyers, in a telephone interview from his Juneau office.

“I think we need to get more information. We need to first corroborate the research that has already been done (in Canada) and reexamine it. The current testing in Canada has looked at over 5,000 farmed fish and 500 wild fish and they have never found a pathogenic virus,” he said.

As for the newly released reports that the virus was detected a decade ago, Meyers said “ It would have been nice if the scientific community had been apprised of those results. If the information had been released then (in 2002) it would have diffused the hysteria of the rediscovery.”

Meyers, who has been in steady contact with his Canadian counterparts, spoke after news emerged of an unpublished report that the virus was detected a decade ago off British Columbia’s coast. The virus is not harmful to humans, but it is known to devastate farmed salmon stocks and there is concern that the ISA could spread to wild Pacific stocks.

Meyers noted that there are different strains of ISA virus, the pathogen strains found in Atlantic salmon, and the ancestral or wild strain, which is non-pathogenic and found in wild stocks in Norway.

The pathogenic strain causes destruction of cells and produces disease in the host fish, while the ancestral strain co-exists very nicely with the host fish without causing disease, he said.

“It’s like a virus in humans,” he said. “Some are benign and some are not.”
What likely happened is that when fish farming was put into place in Canada the ancestral strain mutated into the farmed Atlantic salmon, and it is entirely feasible that we have our own Pacific strain as well, he said.

Canadian authorities have been doing required testing of farmed salmon in that nation for about eight years and no pathogenic strains of the virus have been found, he said. The PCR (polymerase chain reaction) test is a molecular test to detect nucleonic acids from the target organism researchers are trying to detect.

“They have not, to their knowledge, imported any pathogenic virus from wherever they have gotten their Atlantic salmon eggs, he said, “so they need to corroborate the 2002 information of a non-pathogenic strain in wild stocks and then we can go from there,” he said.

Alaska, meanwhile is participating in a planning program with the state of Washington and federal agencies, for similar testing, but it will take a while to establish what will be done, what laboratories will do it, and to be sure surveillance tests are in place.

“We would sample our own fish in Alaska, incorporate those fish into our usual programs for other disease pathogens,” he said. “We do it every year. We look at our own stocks for different viruses and would incorporate ISA virus testing as one of those.”

News of the unpublished 2002 studies has prompted much concern, with the Los Angeles Times calling the issue “Salmongate,” and the News Tribune in Tacoma, Washington expressing its editorial viewpoint that there is something fishy about Canada’s response to salmon virus reports.

Almost a decade ago, it turns out, there were reports of a European strain of ISA in 117 fish from Alaska to Vancouver Island, though none of the fish were sick, the newspaper noted. This led the fisheries biologist Molly Kibenge to surmise that a nonlethal form of ISA may be present in Northwest wild salmon.

“The fear with ISA has always been that it could mutate into a lethal form. Yet Canadian fishery officials failed to follow up on Kibenge’s research and neglected to inform their American counterparts of her findings. The only reason the news is getting out now is that Kibenge and her husband, a noted fish virologist, went public after her request to publish her old data was denied.”

Sen. Maria Cantwell, D-Washington, on Dec. 1 expressed her concern on the status of the virus reports. “These troubling reports reinforce the need for a coordinated, multi-national strategy to control the spread of this virus threat,” Cantwell said. “American and Canadian scientists need to have access to all relevant research on this deadly virus. We can’t afford to leave the Pacific Northwest’s fishery jobs at risk.”

Sen. Lisa Murkowski, R-Alaska, asked the National Oceanic and Atmospheric Administration what details, if any, were known by the US of the previous research, and how this new information is being taken into account in plans to expand testing efforts.

Murkowski said she was troubled when reports appeared earlier this fall of the ISA virus being in fisheries. “But now I am absolutely alarmed that this was not the first our neighbors to the east had heard of this, and had sat on critical information for ten years, putting us 10 years behind in addressing this situation,” she said.