INFECTIOUS SALMON ANEMIA - CANADA: (BRITISH COLUMBIA) PACIFIC, 1ST REPORT
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[1]
Date: Tue 18 Oct 2011
Source: Metro News [edited]
<http://www.metronews.ca/vancouver/local/article/999363--salmon-disease-found-in-pacific-fish>
A highly infectious disease recently found in salmon could have profound effects on both the British Columbia salmon industry and local aboriginal communities, a Simon Fraser University [SFU] professor warned yesterday [17 Oct 2011].
SFU researchers Richard Routledge and Nicole Gerbrandt, in collaboration with independent biologist Alexandra Morton, found the 1st-ever traces of the disease, infectious salmon anemia (ISA), in wild sockeye salmon in the North Pacific Ocean. 2 out of 48 salmon smolts [young salmon] collected from Rivers Inlet were infected with the virus, and researchers fear it could spread.
[byline: Kendra Wong]
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ProMED-mail rapporteur Mary Marshall
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[2]
Date: Mon 17 Oct 2011
Source: PhysOrg.com, Simon Fraser University (SFU) report [edited] <http://www.physorg.com/news/2011-10-lethal-atlantic-virus-pacific-salmon.html>
The highly contagious marine influenza virus, infectious salmon anemia
(ISA) has for the 1st time been officially reported after being found in the Pacific on BC's central coast.
Now it threatens both wild salmon and herring, say biologist Alexandra Morton and Simon Fraser University professor Rick Routledge, whose laboratory led to the discovery of ISA in BC salmon smolts.
Morton is calling for removal of Atlantic salmon from BC salmon farms.
"Loosing a virus as lethal and contagious as ISA into the North Pacific is a cataclysmic biological threat to life," said Morton. "The European strain of ISA virus can only have come from the Atlantic salmon farms. The European strain ISA infected Chile via Atlantic salmon eggs in 2007." Morton says ISA was first found in Norway in 1984. "Since then, there have been lethal outbreaks in every important salmon-farming region around the globe, with the exception -- or so we thought -- of BC. Now we know for sure that it has hit BC.
"The Cohen Inquiry revealed ISA signs have been reported in farm salmon in BC since 2006. The fisheries ministers have written me repeatedly that BC is safe from ISA. Clearly they are not in control of the situation. "If there is any hope, we have to turn off the
source: Atlantic salmon have to be immediately removed."
The virus was found in 2 of 48 sockeye smolts collected as part of a long term study, led by Routledge, on the collapse of Rivers Inlet sockeye populations.
Dr Fred Kibenge of the ISA reference laboratory at the Atlantic Veterinary College in Prince Edward Island made the diagnosis and notified the Canadian Food Inspection Agency (CFIA) of the positive results for the European strain of ISA virus.
Says Routledge: "ISA is a deadly exotic disease which could have devastating impacts on wild salmon and the many species that depend on them throughout much of British Columbia and beyond.
"The combined impacts of this influenza-like virus and the recently identified parvovirus that can suppress the immune system could be particularly deadly."
Morton adds: "The New York Times reported from Chile that the Chilean aquaculture industry suffered more than USD 2 billion in losses, saw its production of Atlantic salmon fall by half, and jobs were lost."
"A scientific study concluded that salmon eggs shipped from Norway to Chile are the 'likely reason' for the outbreak of the virus in Chile in 2007. And nearly 40 million Atlantic salmon eggs have been imported into BC since 1986."
"This is devastating news and something I worked hard to prevent. This has international implications throughout the North Pacific."
Routledge concurs that the only plausible source for the European strain of ISA virus that he found on BC's Central Coast is the Atlantic salmon farms.
Rivers Inlet is on the BC Central Coast in the heart of the Great Bear Rainforest -- 100 km [62 mi] north of a cluster of Norwegian-owned Atlantic salmon feedlots off Port Hardy and 140 km [87 mi] south of Marine Harvest's feedlots near Klemtu.
"The potential impact of ISA cannot be taken lightly," said Routledge.
"There must be an immediate response to assess the extent of the outbreak, determine its source, and to eliminate all controllable sources of the virus -- even though no country has ever eradicated it once it has arrived."
Routledge is a fish-population statistician who was a founding member of the Pacific Fisheries Resource Conservation Council. Morton received an honorary degree from SFU for her work linking sea lice infestation in wild salmon to fish farming in the Broughton Archipelago, which has sparked international attention.
The 2 researchers said that the federal Cohen Commission on the decline of sockeye salmon runs in the Fraser River was told that more than 1000 cases of ISA-type lesions have been reported on BC salmon farms since 2006 -- yet no suspect cases or diagnoses of ISA were reported to the Canadian Food Inspection Agency, or to the World Organization for Animal Health (known as OiE, from its former name of Office International des Epizooties).
Morton, who long ago urged the federal government to close the border to Atlantic salmon eggs as the virus spread in fish farms around the world, says the fact that ISA was found in smolts suggests it has been loose in the Pacific for several years. [At least it has been loose for some time, an exact amount of time is unknown. - Mod.TG]
"Government and industry are clearly not testing effectively. There needs to be an international volunteer epidemiological team formed right now. No one party can own the data. We have to use everything we know to try and contain this."
The researchers say if there is any hope of controlling this disease it must be addressed at the source. The virus is also prone to mutating into increasingly virulent forms.
ISA virus and BC salmon farms
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ISA has only appeared where salmon are raised in aquaculture and has spread worldwide since first being reported in Norway in 1984. ISA can infect herring, as well as, salmon. ISA was first reported in Eastern Canada in 1996 and continues to cause problems there.
In 2007, ISA began in a non-lethal form in Chile and became a virulent epidemic killing 70 per cent of the farm salmon. Chile does not have wild salmon.
In January 2009, a group of Canadian scientists, including David Suzuki, signed a letter warning the Canadian fisheries minister of the risks of introducing ISA into BC. Ex-minister Gale Shea refused to acknowledge that ISA reached Chile in eggs, although Cermaq, a state-controlled Norwegian aquaculture company that has become one of the principal exporters of salmon from Chile, endorsed a scientific study concluding that salmon eggs shipped from Norway to Chile were the 'likely reason' for the outbreak of the virus in Chile in 2007.
ISA is known to exist in a non-lethal state, causing low mortalities on salmon farms and then mutate into highly virulent strains when contained in salmon farms.
Forty million Atlantic salmon eggs have been introduced into BC since 1986. The Fish Health Certificate that must be signed by the foreign hatcheries does not specifically request ISA virus reporting (Manual of Compliance, Ottawa 2004, page 51).
Fisheries and Oceans did not require reporting of ISA virus on salmon farms, but the Canadian Food Inspection Agency intervened in January
2011 and made ISA virus a reportable disease (<http://www.gazette.gc.ca/rp-pr/p2/2010/2010-12-22/html/sor-dors296-eng.html#REFa>;
see "Regulatory Impact Statement" 2/3 down the site.)
As a participant of the Cohen Inquiry, Alexandra Morton read the BC Ministry of Agriculture and Lands disease reports and found over 1100 reports of "classic" ISAV lesions in farm salmon.
Justice Cohen was petitioned by her lawyer, Greg McDade, to allow her to report these to the Canadian Food Inspection Agency, but the CFIA appear to have merely called the fish farmers and asked if they had ISA virus; no testing was done.
In 2004, Dr Laura Richards, director general of DFO [Department of Fisheries and Oceans] Science, Pacific Region, successfully petitioned on behalf of the fish farm industry to waive the Canadian Fish Health Protection Regulations to allow Atlantic salmon eggs from a hatchery that does not meet Canadian regulations (CohenCommision.ca Exhibit no 1683).
Since then all Atlantic salmon eggs have come from this hatchery. In
2005 an entire shipment was destroyed due to viral concerns (CohenCommission.ca Exhibit no 1684). There is no record of testing the eggs that arrived in BC from the same hatchery the previous month (CohenCommision.ca Exhibit no 1683).
More information: Report on ISA to World from Dr Fred Kibenge, University of Prince Edward Island <http://www.oie.int/eng/A_aquatic/Docs/Presentations/1.11Kibenge.ppt>.
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This may be extremely important and clearly shows a movement of the disease. It will be interesting to see the response of the government with regard to the Atlantic fish.
This highly contagious disease can be insidious, with an initially low mortality rate; however, the cumulative mortality can sometimes exceed 90 per cent if the disease remains unchecked. Infectious salmon anemia was first described in Norway in 1984, and it continues to be a problem in that country despite control measures. Since the late 1990s, outbreaks have also been reported in other locations. This disease devastated the salmon industry of the Faroe Islands in 2000, and an epizootic in Scotland in 1998-1999 cost an estimated USD 32 million to eradicate. ISA has been a recurring problem in Chile, the Cobscook Bay in Maine, and the Bay of Fundy in New Brunswick, Canada.
In New Brunswick, it results in annual losses of about USD 4.8-5.5 million to farmers, and millions of fish have been culled in control efforts. New outbreaks can also occur in areas where this disease was absent for many years. In 2009, an outbreak was reported again in Scotland.
Understanding of the epidemiology of ISA is still incomplete, which complicates its control. The reservoirs for the virus are not known, but experiments have shown that several species of salmonids can carry virulent ISA viruses asymptomatically. These viruses could cause outbreaks if they are transmitted to farmed Atlantic salmon.
Noncultivable, apparently nonpathogenic, isolates have also been detected in wild salmonids. Small changes in these viruses, analogous to the mutations that allow low pathogenicity avian influenza viruses to become highly pathogenic, may allow them to become more virulent.
Recent evidence also suggests that some ISA viruses may cause illness in species other than Atlantic salmon. One isolate has been linked to illness among farmed Pacific coho salmon in Chile, and a highly virulent strain can cause disease in experimentally infected rainbow trout.
Infectious salmon anemia virus (ISAV) is a member of the genus _Isavirus_ in the family Orthomyxoviridae. Hemorrhagic kidney syndrome is an old name for the disease in Atlantic salmon. In coho salmon, it has also been called icterus syndrome.
The 2 major lineages of ISAV are the European genotype (or genotype I) and the North American genotype (or genotype II).
Epidemiological studies suggest that ISAV can be transmitted indirectly in water and on fomites, as well as by close contact between fish. Horizontal transmission can occur in both freshwater and seawater. Sea lice (_Lepeophtheirus salmonis_ and _Caligus_ sp.) may be mechanical vectors. These parasites could also increase the susceptibility of fish by increasing stress. In the laboratory, ISAV remained infective when held at 15 deg C (59 deg F) for 10 days or 4 deg C (39 deg F) for 14 days. There was a 3 log (1000-fold) reduction in the viral titer when ISAV was held at 4 deg C (39 deg F) for 4 months. It was stable between pH 5.7 and pH 9.0. Because the virus's survival can also be affected by factors such as UV irradiation and components in the water which can either bind or inactivate it, it is difficult to estimate the length of time before ISAV is inactivated in nature.
Infectious salmon anemia should be a consideration in Atlantic salmon with increased mortality and signs of anemia, or lesions consistent with this disease. It should always be investigated if the hematocrit is less than 10 per cent.
The differential diagnoses for infectious salmon anemia include other causes of anemia and hemorrhages, as well as winter ulcer and septicemias caused by _Moritella viscosa_.
Outbreaks of infectious salmon anemia can be diagnosed by virus isolation, the detection of antigens and RT-PCR. A few isolates from sick salmon have been difficult to culture, even when viral nucleic acids can be found. The avirulent isolates carried subclinically in wild salmonids can usually be detected only by RT-PCR.
Portions of this comment have been extracted from <http://www.cfsph.iastate.edu/Factsheets/pdfs/infectious_salmon_anemia.pdf>
- Mod.TG]
[see also:
Infectious salmon anemia - Chile 20110730.2287 2010
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Infectious salmon anemia - Chile 20100820.2909 Infectious salmon anemia - Chile (02): (MA) 20101109.4064
2009
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Infectious salmon anemia - Chile 20090715.2526 Infectious salmon anemia - Chile (02): origin 20090719.2568] .................................................sb/tg/mj/sh/ll
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