Symptoms alone do not prove disease
By Gary D. Marty, Times Colonist September 8, 2011
I was disappointed to read Times Colonist columnist D.C. Reid's Sept. 6 column, "Hell to pay for letting ISA virus into the Pacific."
I am the board-certified veterinary pathologist that Reid referred to as the "province's fish-table pathologist." Reid also attributed to me a statement that I did not make: "ISA, what ISA?" False attributions like these mislead the public.
Reid wrote "you will be staggered by how many hundreds of times . [classic symptoms of ISA] . were found in fish farm Atlantic salmon."
In my view, the public is also misled when a common "symptom" is attributed to a disease that does not occur in B.C.
Indeed, every one of the hundreds of fish with "classic symptoms of ISA" in the provincial fish health database was tested for the ISA virus using a highly sensitive and specific PCR test.
All fish tested negative - no virus. From 2003 to 2010, the province tested 4,726 dead farm fish for the ISA virus, and all fish tested negative - no virus.
These results are available on public websites summarized in Cohen Commission exhibit No. 1471, Aug. 22.
The provincial database that contains "classic symptoms of ISA" is available to the public as part of the Cohen Commission proceedings. However, any public comment on these medical records needs to respect ethical guidelines as outlined by the College of Veterinarians of B.C.
Gary D. Marty, D.V.M., Ph.D.
Fish pathologist, Ministry of Agriculture Abbotsford
PAA Reference Link:
Cohen Commission - Exhibit 1471 August 22, 2011
Publicly available PCR test results for infectious salmon anaemia virus (ISAV) in British Columbia farmed salmon over the past 8 years (2003 - 2010). Data were compiled as part of the BC Fish Health Auditing and Surveillance Program.
Year # Positive # Negative
2003 0 648
2004 0 675
2005 0 586
2006 0 644
2007 0 763
2008 0 588
2009 0 585
2010 0 237
TOTAL 0 4,726
Sources:
BC Animal Health Centre web site:
http://www.agf.gov.bc.ca/ahc/fish_health/index.htm
BC Centre for Aquatic Health Sciences web site:
http://www.cahs-bc.ca/fish-health-audits.php
Note: Exhibit 1471 can be accessed on the Cohen Commission website by selecting August 22 on the Calendar & Transcript Page. http://www.cohencommission.ca/en/Schedule/
