Doubts mount on suspectful ISA findings
Fis, November 7, 2011
Results from two more rounds of sampling are casting further questions on suspect findings of Infectious Salmon Anemia (ISA) in British Columbia.
Released on Wednesday, reports from the University of Bergen (Norway) and from the Prince Edward Island lab run by Dr. Fred Kibenge both show additional positives and both raise serious questions about those positive results. Despite what some activists may claim, ISA has not been confirmed in British Columbia.
In the case of the Dr. Are Nylund at the University of Bergen, 48 samples were run with one coming back as a weak positive result (see the report here). When that sample was re-run - another 32 times - the already-delicate positive result could never be reproduced. That is, the two original samples that had tested positive in results released weeks ago, tested negative at the Bergen lab.
In an interview, Dr. Nylund says specifically that it cannot be concluded from his results that ISAv has been detected in BC. He added that the test material was of poor quality when it was received and nothing in these results tells us whether this has any impact on wild or farmed salmon.
Results from Dr. Kibenge's lab show positives in three of 20 samples tested. One of three tested positive of the European genotype. But this time Dr. Kibenge includes in his notes some important qualifiers for the public: namely that these results do not mean that the fish had ISA or ISAv or that either is present in the area where the subject fish came from. For confirmation, the virus needs to be isolated - testing that is underway but will take another six weeks. He adds also that his laboratory had no participation in the collection of these samples or in their custody prior to receiving them - which means they cannot guarantee their integrity.
These results raise important questions about the initial results publicized by Simon Fraser University on 17 October. While BC's salmon farmers remain concerned about the possibility of ISAv being in British Columbia, this recent news highlights the importance of good procedures and solid science before announcements such as that made a few weeks ago.
While the BC Salmon Farmers Association (BCSFA) is still awaiting the results of follow-up testing on those original samples, the Minister of Fisheries and Oceans and Minister of Agriculture and Agri-Food Canada said in a statement: "After initial investigations, we are concerned that proper protocols may not have been followed in the testing and reporting of these findings."
The industry continues to urge the Canadian Food Inspection Agency to complete and release results of their testing as soon as possible. Salmon farmers could be negatively affected if this virus is in BC- as research shows that Atlantic salmon are highly susceptible to the disease while Pacific salmon are relatively immune to it.
The association states that what they do know clearly is that nearly 5,000 samples tested from their farms have all been negative for ISA. And they know ISA is not present on their farms.
"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: a surveillance programme that is timely, organized, responsible to the public and appreciable to a wider scientific community," they added.
According to BCSFA, many questions still remain so they urge the Canadian Food Inspection Agency to provide conclusive results soon.
Retests show no conclusive evidence of ISA infection
Fis, November 4, 2011
New test results from the University of Bergen in Norway show there is no conclusive evidence that wild fish in British Columbia (BC) have been infected with the infectious salmon anemia (ISA) virus, Mainstream Canada communicated in a statement.
Dr Are Nylund reanalyzed 48 samples of Pacific salmon and determined that none of the fish had ISA. The samples were previously studied by Dr Fred Kibenge at the University of Prince Edward Island (UPEI).
Nylund tested one of the samples 33 times; in that sample he found one weak positive result and 32 negative results.
"This means that I could not confirm the results from Kibenge, since he found two clearly positive findings and concluded that this had European origin," Nylund explained. "This also means that a virus having genetic similarities with ISA or something totally different may be picked up by the test. Therefore, we need to sequence/genotype the virus to provide serious comment on the origin."
This could represent a previously unknown type of Pacific Ocean virus and it might have its origins in ancient evolution.
"Today there are several examples of pathogens that are related and which have a North Pacific and a North Atlantic type," he said. "The reason for this is that the salmon and some of its pathogens in the Pacific and Atlantic once had the same origin, but they have developed differently as they have been geographically isolated over a long time."
Thousands of farmed and wild salmon have been tested for the ISA virus in BC. All tests were negative.
However, two weeks ago anti-aquaculture activist Alexandra Morton claimed Pacific salmon collected by Simon Fraser University researchers was infected with the European ISA virus. She made the claim before the tests were even concluded, Mainstream said.
The new test results provide a good scientific control for those results, the company stated.
Kibenge cautioned in his report that "the presence of ISA virus sequences in the tissue samples does not imply that the subject fish had ISA or that ISA is present in the area where the subject fish were collected from." More genetic testing is necessary to conclude if the latest results from UPEI are significant or skewed because of poor-quality samples, Mainstream noted.
The Canadian Food Inspection Agency (CFIA) is now running “proper tests” to see if it can reach the same conclusions and will be investigating the chain of custody.
“We urge the CFIA scientists to quickly conclude their investigation and publish their findings. Mainstream, along with the rest of the BC salmon farming industry, has offered to provide further samples for testing by CFIA and are advocating for more sampling and testing of our region's wild fish and for continuation of the surveillance programme,” Mainstream added.
