Photo courtesy of: Mainstream Canada
A British Columbia fish farm has been placed under quarantine and is now depopulating due to the detection of the IHN (Infectious Haematopoietic Necrosis) virus. IHN is not considered to be a threat to wild Pacific Salmon but it can be devastating to the Atlantic salmon farmed on the West Coast of Canada.
During routine fish health tests on Monday, May 14, Mainstream Canada's Dixon Bay farm tested positive for IHNv. Third-party lab PCR test results confirmed the presence of the virus and Mainstream Canada has begun depopulating the site under the watch of the Canadian Food Inspection Agency.
"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.
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.
Fish removed from the site will be euthanized and transported to a composting facility for disposal. Strict biosecurity protocols will be followed during all stages of this process.