Salmon Virus Controversy in British Columbia; Study Says Found in Certain Amounts

A feared virus that occurs among farmed salmon in Europe may have been detected in Canada's British Columbia (B.C.) according to a recently published study, although the Canadian Food Inspection Agency has not yet declared presence of the virus, a European variant of infectious salmon anaemia virus (ISAV), on the West Coast. In 1996, a case of the virus was detected in Atlantic Canada. No signs of it have yet been detected in regular testing in Washington state, which borders B.C.

Death to infected fish can occur over weeks or months. The disease is the most feared virus in the salmon farming industry. The findings were recently published in the peer-reviewed The Virology Journal, from the international publishing house Springer Nature.

ISAV's presence in B.C. was found by a study that tested more than 1,000 farmed and wild fish. This was an extension of a preliminary study that announced in 2011 that ISAV had been found in the province. However, researchers say in the report that in the more recent stages of the study, a code was cracked to detect ISAV as a mutation in the fish. The study also found evidence of ISA virus in sea lice, which could spread it to wild salmon.

"I have been following this work for many years. ISA virus is a serious matter," Dr. Daniel Pauly, at the University of British Columbia (UBC), said in a release. "A member of the influenza family in open ocean feedlots is a risk Canada should not be taking on the west coast."

The fear in B.C. and for the streams along the U.S. border is that ISAV could spread from farms to wild salmon. In a previous situation of ISAV infection in Chile in 2007, where the disease was not contained, $2 billion in damages resulted.

"The potential that viruses such as ISAV are contributing to widespread decline in sockeye salmon populations cannot be taken lightly," co-author Dr. Rick Routledge said in the release. "The findings in this paper should lead to development of more sensitive screening for this specific virus. This opportunity needs to be pursued with vigor."

More has been learned since the early results of the study in 2011, said report co-author Alexandra Morton in the release. "This was a difficult strain of ISAV to detect, because of a small mutation. It is easy to see how it was missed, but we have cracked its code. It is critical that we learn from what happened to Chile. In my view, this work gives B.C. and our U.S. neighbors the opportunity to avoid tragic consequences."

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