Canadian Government Can't Confirm B.C. Salmon Virus
NW Fishletter #296, November 11, 2011
Canadian government officials said Nov. 8 in a joint-agency press conference they were unable to confirm the presence of the ISA virus in samples of wild B.C. sockeye smolts. The samples had shown signs of the virus in previous tests in a different lab.
Testing for confirmation of the original results has been going on since mid-October, in collaboration with Fisheries and Oceans Canada, the province of British Columbia, and the Atlantic Veterinary College at the University of Prince Edward Island, where the original testing was conducted, said Dr. Cornelius Kiley of the Canadian Food Inspection Agency.
"Based on analysis conducted at the DFO national reference laboratory, there have been no confirmed cases of infectious salmon anemia in wild or farmed salmon in British Columbia," said Kiley. He said all 48 original samples had been tested by the DFO lab and all results were negative for the virus.
Kiley said the findings were consistent with the results of a Norwegian scientist (see Story #2) who tested other samples from the sockeye and presented his findings to the CFIA.
"All additional samples that have been collected and tested as part of this investigation have also been negative for infectious salmon anemia," said Kiley. "However, these supplementary results must be considered inconclusive because of the poor quality of the samples. Additional testing continues and will also be provided when ready."
Kiley said any suspected cases of ISA must be confirmed by the DFO lab under terms of Canada's national aquatic health program, and investigators are also looking at "how the samples were collected, handled, transported, sorted and stored. This information will be critical in validating the virus test results and establishing Canada's health status for this disease."
Kiley noted that over 5,000 wild and farmed salmon have been tested by the federal and provincial B.C. governments and none had ever tested positive for the ISA virus. Current testing levels are being assessed, "and will increase surveillance activities as required." He said the virus has no adverse impact on human health but could have serious impacts on aquatic animal health and the economy.
DFO official Stephen Stephen said the agency's lab in Monckton, New Brunswick, is the national ISA virus reference laboratory. He said the team of scientists there have many years of experience in testing all kinds of finfish, crustacean and mollusks.
The message from the government scientists was considerably less scary than what has been carried in most media stories over the past several weeks, where anti-farmed fish advocates blamed B.C.'s farmed salmon industry for introducing the ISA virus into wild B.C. salmon. "As far as we are aware," said Dr. Paul Kitching, B.C.'s chief veterinary officer, "Pacific species of salmon are resistant to infectious salmon anemia virus infections and disease although it does cause disease in Atlantic salmon.
"In fact, only the PEI lab had reported positive coho salmon , and that was in Chile in 1999. I was therefore surprised to hear that two out of 48 sockeye salmon had tested positive for the European strain of ISA. But not only that, samples of chinook, coho and chum, all specific species of salmon, taken almost at random, had also tested positive by the same laboratory in PEI. However you look at these results, statistically, epidemiologically, or virologically, they defy common sense.
"Up to this time, we have seen no ISA virus or disease in B.C. The laboratory in Prince Edward island did not confirm the positive PCR [polymerease chain reaction] tests that they reported, was definitively part of the infectious salmon anemia virus, let alone part of the whole living virus. For anyone to say that infectious salmon anemia virus is present in B.C. on the basis of the Prince Edward Island results is misrepresenting the science, either because they do not understand the science or for other reasons. And I can also say, as editor-in-chief of an international veterinary journal, this would be considered poor science and not likely publishable in a refereed scientific journal."
Dr. Kiley said they considered the one sample found by Norwegian scientist Are Nylund that tested positive for the virus to be negative, since Nylund could not repeat the results. "The many times he did it, it was not repeatable," said Dr. Kiley. "So we would consider that, technically, from a CFIA viewpoint, negative."
"There's no evidence that ISA virus occurs in the waters off British Columbia," said Dr. Kiley, who added that more tests are continuing. Kiley said a broader sampling of tissues -- "hundreds" -- beyond the original 48 has also shown no presence of the virus.
In response to a reporter's question whether they would share the samples with U.S. researchers, Peter Wright, who heads DFO's research and diagnostic laboratory system, said the quality of the samples was poor. He said his lab used a separate PCR test that looks at the host's RNA, and found most of them "partially, and I say, over the half-way mark, or totally, totally degraded. Sharing those samples would not be good science. They're in poor condition, we received them in poor condition, and moving them out anywhere else is not going to help anybody."
Wright said the negative findings in the original 48 samples were confirmed because they came from kidney extracts from a DFO lab that had received them but had not yet done any testing. With only some degree of degradation in these samples, Wright said the negative findings gave them some degree of confidence in their results, rather than calling them "inconclusive."
Others took issue with the scientists' view that inconclusive results from the poor samples were classified as "negative" by the DFO lab. In an interview with The Vancouver Sun on Nov. 9, wild-fish advocate Alexandra Morton, who had gathered the original samples and sent them to the PEI lab for testing, was quoted saying, "If the samples are degraded, what confidence can we have in the tests?"
"This is a significant result for everyone involved: researchers, regulators, wild salmon advocates, salmon farmers and our coastal communities," said Mary Ellen Walling, executive director of the BC Salmon Farmers Association, in a statement. "After seeing the original news distributed in such an inflammatory way, we hope this update will allay those concerns."
The Cohen Commission which has been gathering evidence over the past year or so to determine the causes behind the 2009 Fraser sockeye run failure, said it would convene a special 2-day session later this month to look into the latest findings. -Bill Rudolph
