Cohen Aquaculture Daily – December 15, 2011
Transcript: December 15, 2011 Hearing Transcript
Summary: Due to the recent detection of ISAv in wild salmon in BC by a lab in UPEI and Are Nylund’s lab at the University in Bergen, Norway, the Cohen Commission added three days of hearings to examine this issue.
- There is a significant difference between the detection of a virus in fish and the presence of the disease associated with this virus in fish.
- In the past, Dr. Miller tested fish with an assay that included ISAv primer segment 6 (ISAv is an 8 segment virus), but after the recent positive tests for ISAv in wild salmon in BC, she retested her samples using more appropriate assays based on current scientific literature. Her lab began testing with assays that included ISAv primers segments 7 and 8.
- In Miller’s recent testing, positive test results for sequences of ISAv caused her lab to contend that an assay that includes a primer from segment 7 is the most appropriate test for the strain found in BC.
- Miller ran the assays in her lab without positive controls because the entire viral sequence was unknown at that point in time. The absence of a positive control limits the ability of the test, however it also eliminates the possibility of contamination and reduces the possibility of a false positive test through contamination.
- Miller reported that the ISA sequence her lab found was at minimum 5% divergent from all known ISAv strains, so the purported virus may be a previously unidentified strain of ISAv.
- Dr. Miller sent 96 samples that her lab found positive to a DFO lab in Moncton. The DFO lab which is directed by Nellie Gagné tested the samples and got negative results for ISAv. Subsequently, Miller retested the samples using the same tests Moncton used and didn’t get positives either. Miller concluded that this may imply the DFO Montcon lab may not have been using the most appropriate tests for the purported ISAv strain in BC.
- In response, Gagné said “we’re not trying to not detect the virus”, and implied the assays her lab uses are recognized in the published scientific literature to test for recognized strains of ISAv.
- The 2004 draft manuscript by Molly Kibenge which reported positive tests for ISAv sequences was not published according to Dr. Kibenge because the results could not be repeated in the DFO Moncton lab and Dr. Simon Jones of DFO suggested that the samples may have been contaminated.
- Some possible reasons for different results in different labs include:
- the software associated with reading the results of testing can cause differing results
- different labs may use different testing methods
- testing methods have been developed based on research done on Atlantic salmon tissue, therefore the tissues used from wild salmon species may not be the most appropriate.
- Miller stated that she did not get full cooperation from some fish farm companies in attaining farm fish samples to test for viruses.
- The BC Salmon Farmers Association brought to evidence a letter to the minister as an offer to test their fish.
- The BC Salmon Farmers Association implied they wanted more control over some of Miller’s research and they wanted her to agree to only test for parvo virus (i.e., not ISAv).
- No panel member recognized the provincial salmon farm auditing methods as scientifically published methods used internationally to test for ISAv.
- Miller noted that Dr. Gary Marty from the province produced a document that detailed internationally recognized methods to test for ISAv to the Cohen Commission but these weren’t the methods his provincial lab was using to test farm fish for ISAv.
- Miller stated that it was generally recognized that DFO staff weren’t supposed to communicate about ISA over email within the Department of Fisheries and Oceans.
- Miller said since she reported positive tests for ISAv she felt alienated in the department and that she may have been excluded from some disease conservations.
- Miller was a bit surprised at the December 2, 2011 DFO statement from Minister Keith Ashfield that ISA was not in BC.
- It is possible that this virus could mutate into a pathogenic strain.
- A post doctorate in Dr. Miller’s lab—Dr. Brad Davis—used a retrospective statistical analysis on their microarray data and found a strong host influenza response associated with the samples that tested positive for ISAv. These results suggest a correlation between positive testing of ISAv and the expression of a flu-like response in the fish.
- Miller tested some farm Chinook from Creative Salmon and 25% were positive for ISAv. She also found piscine reovirus which potentially could lead to heart-skeletal muscular inflammation in the farm fish, which has never been reported in BC. In addition, she found the piscine reovirus in a similar percentage of wild sockeye.
- Nylund said piscine reovirus potentially caused 10% mortality in Chile farms.
- Miller tested some archived fish samples and found positives for ISAv in Fraser sockeye going as far back as 1986. She also found positives in pink salmon.
Witnesses – Infectious Salmon Anemia virus (ISAv):
- Nellie Gagné – Molecular Biology Scientist and Laboratory Supervisor, DFO, Moncton
- Dr. Fred Kibenge – Chairman, Department of Pathology and Microbiology, Atlantic Veterinary College, University of Prince Edward Island
- Dr. Kristi Miller – Head, Molecular Genetics, DFO
- Dr. Are Nylund – Professor, University of Bergen, Norway
See evidentiary documents page for a listing of key exhibits discussed at the hearings.
News Coverage resulting from December 15th Cohen hearings: List is updated as additional media is published.
- Westerly News; January 5, 2012; “Salmon virus may be linked to local fish”
- CBC; December 15, 2011; “Salmon virus in B.C. for decades, say biologists”
- Vancouver Sun; December 15, 2011; “B.C. sockeye test positive for potentially deadly virus, inquiry told”
- Globe and Mail; December 15, 2011; “Virus present in B.C. salmon for decades, inquiry told”