Mainstream Canada Dixon Bay IHN update: depopulating the site - Mainstream Canada, Thu, 2012-05-17
Mainstream Canada has begun depopulating its Dixon Bay farm site, after IHNv (Infectious Haematopoietic Necrosis virus) was detected.
IHNv can cause the Infectious Haematopoietic Necrosis disease in farmed Atlantic salmon.
Samples collected during routine fish health disease screening were submitted to the provincial government's Animal Health Centre lab in Abbotsford, B.C. The lab detected the virus with qPCR tests and confirmed it by genetic sequencing. Histopathological results also confirmed that the fish were affected with the disease caused by the IHN virus...
Read more at:
http://www.mainstreamcanada.com/mainstream-canada-dixon-bay-ihn-update-depopulating-site-0
PAA Note: Release includes IHN Questions and Answers Info.
Mainstream Canada farm north of Tofino tests positive for IHN virus - Mainstream Canada, Tue, 2012-05-15
During routine fish health tests May 14, Mainstream Canada's Dixon Bay farm tested positive for the IHN (Infectious Haematopoietic Necrosis) virus.
Third-party lab PCR test results have shown the presence of the virus. Sequencing has confirmed the presence of IHN virus in these fish.
The farm site has been isolated and is currently being prepared for depopulation, if deemed necessary upon completion of the investigation. The company is following strict protocols to limit the spread of the virus. The protocols are part of Mainstream Canada's fish health management plan as well as an industry viral disease management plan.
The Canadian Food Inspection Agency (CFIA) has been notified and is investigating the finding. Fisheries and Oceans Canada's National Laboratory is conducting confirmatory testing.
"We are very concerned about this fish health event and are taking every step to make sure it is contained and any risks minimized," said Fernando Villarroel, Mainstream Canada's managing director. "This shows our disease monitoring programs work. We were able to quickly detect IHN while in its early stages and react decisively. Early detection is crucial to minimizing the risk in any fish health situation.
The IHN virus is naturally carried by Pacific salmon, trout and herring. Studies show wild Pacific salmon have a natural resistance to the virus and very rarely suffer ill effects from it...
Read more at:
http://www.mainstreamcanada.ca/mainstream-canada-farm-north-tofino-tests-positive-ihn-virus-0
PAA Note: News Release includes IHN Fact Sheet
Reference Link: Mainstream Canada News Page
More information about IHN can be found at:
BC Salmon Farmers Website - Hot topics - IHN
http://www.salmonfarmers.org/hot-topics - www.salmonfarmers.org/sites/default/files/hot-topics/ihn.pdf
Below are some frequently-asked questions and answers released by Mainstream Canada:
What is IHN?
IHN or Infectious Haematopoietic Necrosis is caused by a virus native to the West Coast of North America. It is an infectious disease of trout and Pacific salmon. The virus can be carried by wild salmon, trout and herring. IHN poses no human health risk.
Where does IHN come from?
IHN occurs naturally in wild fish. They can carry the virus without the virus ever causing any disease. There is a very low risk of IHN affecting wild salmon due to the fact that wild fish are more resistant to the virus, having lived with background levels of the virus in the ocean for centuries.
How do farmed salmon become infected?
Atlantic salmon, due to the fact that they are not native to the area and have not had hundreds of years to develop a natural resistance, are susceptible to the virus and the disease it causes. The virus can be spread horizontally (from fish to fish) in both freshwater and saltwater, including from wild fish to Atlantic salmon. It can also pass vertically (from parents to offspring) through infected ovarian fluid.
How serious is IHN?
This virus can cause high mortalities in farmed salmon and has done so in the past. Since then, management practices have been put in place to prevent the virus from entering farms, and to quickly react if the virus is detected on a farm.
What do BC Salmon Farmers do to prevent IHN?
Good overall fish health conditions decreases the susceptibility of the fish to infection. We have strict control policies and sound hygiene practices to stop the virus from entering the sites. This includes disinfection of fertilized eggs and regular fish health checks to screen for the presence of the virus.
What would BC Salmon Farmers do if an IHN-infected fish was discovered?
The three Atlantic salmon farming companies in BC have a salmon farming industry viral disease management plan to co-ordinate their reaction in the eventuality that IHN infected salmon are discovered.
These include protocols for limiting the spread of the virus, as well as the secure disposal of infected fish.
IHN is a reportable disease in Canada. If the virus is discovered, the appropriate government agencies must be contacted immediately (DFO, CFIA).
News Coverage of Interest:
Fatal IHN virus detected in B.C. Atlantic farmed salmon for first time since 2003
By Mike Hager, Vancouver Sun May 16, 2012
For the first time in nine years Atlantic salmon farmed in British Columbian waters have tested positive for a virus that can be rapidly fatal to them, but is endemic in wild Pacific salmon and largely a low risk.
Mainstream Canada announced today that fish at its Dixon Bay farm north of Tofino tested positive for Infectious Hematopoietic Necrosis (IHN). The virus is harmless to humans, but attacks the kidneys and spleen of salmon and can lead to rotting flesh and organ failure. IHN has been present in the waters of B.C. for hundreds of years and wild salmon have developed a resistance to it, though young salmon and sockeye can be vulnerable to it, according to fish virologist James Winton.
The Canadian Food Inspection Agency will arrive at the farm tomorrow for testing as Mainstream waits to see if and how many of the roughly 500,000 farmed fish on site will have to be culled.
"This year now turns out to be a very bad year for IHN virus and we still don't completely understand why," said Winton, on the phone from Seattle where he works for the U.S. Geological Survey. "A lot of the sockeye were coming back with higher percentages and higher amounts of the virus, so it's not surprising that we're seeing a cycle again in some of the farms.
"Atlantics - they haven't evolved with this virus so they're sort of susceptible to all strains of [IHN]."
Mainstream spokeswoman Laurie Jensen said the virus may have been passed on to the contained salmon by a wild fish species passing through the area and that IHN is "a fact of farming and husbandry."
Mainstream operates 27 farms in B.C., and 17 of those in the Tofino area. Those 17 are conducting IHN tests of their fish Jensen said.
If IHN is discovered, a company must call in the CFIA as well as Fisheries and Oceans Canada.
The infected fish are all young and about one kilogram, Jensen said. The company usually grows them until they are five or six kilograms before killing and selling them.
She acknowledged that the company's media release was part of a concerted PR strategy.
"There's a lot of misinformation around salmon farming, so, yes, we are trying to be more transparent and open and let people know exactly what we do."
IHN can be spread from fish to fish in both freshwater and saltwater, and the virus itself can persist in the water for days Winton said. It can also be passed down from parents to offspring through the ovarian fluid surrounding the eggs Winton said. The virus is incurable once contracted and a commercial vaccine is available, but it is relatively expensive Hinton said.
The virus was first recognized in the 1950s and B.C.'s Atlantic salmon farms have seen outbreaks in 1992, 1995, 1996,1997 and 2001 to 2003 according to the Ministry of Agriculture.
