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Author Topic: IHN Virus Confirmed on West Coast Salmon Farm  (Read 1690 times)

aquapaloosa

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IHN Virus Confirmed on West Coast Salmon Farm
« on: May 16, 2012, 02:31:57 PM »

Thought I would post this in the factual version before it gets re-delivered, re-interpreted, by you know who.

May 15, 2012
Mainstream Canada farm north of Tofino tests positive for IHN virus
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 completeion 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.
However, the virus causes Infectious Haematopoietic Necrosis disease in farmed Atlantic salmon. Since
Atlantic salmon are not native to the Pacific coast, they have not had hundreds of years to develop a
natural immunity to the virus, like their Pacific cousins. The disease can cause high degrees of mortalities
on Atlantic salmon farms if not quickly managed and contained. 
“This is the first diagnosis of IHN among farmed Atlantic salmon in BC since 2003. Although IHN kills up
to 100% of exposed Atlantic salmon, wild salmon in marine waters are very resistant to IHNV infection,”
said Gary Marty, fish pathologist for the BC Animal Health Centre. 
A lab study (Traxler et al, 1993) demonstrated this resistance under controlled laboratory exposure
conditions. 25 virus-free sockeye salmon were added to a tank with 10 IHNV-injected Atlantic salmon.
After 37 days, only 1 of the 25 sockeye salmon died, and the viral load in that fish was low.
 
For more information contact Laurie Jensen, Communications and Corporate Sustainability Manager, at
laurie.jensen@mainstreamcanada.com or 250.286.0022 ext. 2232 

 
BACKGROUNDER: IHN Fact Sheet
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 does Mainstream 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 Mainstream 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).
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Bassonator

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #1 on: May 16, 2012, 03:18:24 PM »

Thanks for that post and I know what you mean..... ;D
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aquapaloosa

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #2 on: May 16, 2012, 03:21:39 PM »

 ;)
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troutbreath

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #3 on: May 16, 2012, 03:30:48 PM »

"Studies show wild Pacific salmon have a natural resistance to the virus and very rarely suffer ill effects from it."


" 25 virus-free sockeye salmon were added to a tank with 10 IHNV-injected Atlantic salmon.
After 37 days, only 1 of the 25 sockeye salmon died, and the viral load in that fish was low."



So a one off "scientific" study showed that one in 25 Sockeye died from exposure after 37 "short" days. One would have to look at that study to see how old these fish were etc to get an idea what shananagins are being served up as "scientific fact". Who knows maybe all the fish died 2 weeks later. ???
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aquapaloosa

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #4 on: May 16, 2012, 03:38:54 PM »

Post the study buddy. ;D
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aquapaloosa

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #5 on: May 16, 2012, 03:49:34 PM »

http://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CFYQFjAA&url=http%3A%2F%2Fwww.dfo-mpo.gc.ca%2FLibrary%2F338115.pdf&ei=iy60T5jxHaKe2AWXz8wZ&usg=AFQjCNF8xNywCKuXuNoeh4NzbC_l8VZ1Lg&sig2=11IJWYs21KLA7UcvWVMZ9w

I wonder what some of the others have to say about this study done in 1991?

The numbers seem quite different from what TB's post says.  See the table at the bottom.
« Last Edit: May 16, 2012, 03:56:24 PM by aquapaloosa »
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troutbreath

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #6 on: May 16, 2012, 04:20:48 PM »

"See the table at the bottom"


Read the report itself and you clearly see that sockeye were dying from being exposed to the virus in sea water. Also mentions that they don't know the affect on Chinook. I don't know how you get any sense there is no threat to other fish from that study?
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Dave

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #7 on: May 16, 2012, 05:06:33 PM »

Pacific salmon and sockeye especially have always been susceptible to IHN - it's the west coast virus and fish rearing facilities take great precautions to prevent it's spread.  Last I heard, it's been found in all Fraser sockeye stocks, with the possible exception of the upper Pitt  Nothing new there but it's important to note these farmed Atlantic's were most likely infected by wild fish, and not necessarily salmon.
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aquapaloosa

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Re: IHN Virus Confirmed on West Coast Salmon Farm
« Reply #8 on: May 16, 2012, 05:20:03 PM »

Quote
I don't know how you get any sense there is no threat to other fish from that study?

That is another assumption on your behalf. I stated no such thing. 


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