May 9, 2018
Atlantic salmon-related virus may also cause disease in Chinook salmon, study finds
For the first time, a new study has found that the Piscine orthoreovirus (PRV), which causes disease in farmed Atlantic salmon, may cause a related disease in Chinook salmon, a species of Pacific salmon, in British Columbia, Canada.
"The results of this study are significant because they show - for the first time - strong evidence that the same strain of PRV that causes heart and skeletal muscle inflammation disease (HSMI) in Atlantic salmon is likely to cause disease in at least one species of Pacific salmon", said Dr. Brian Riddell, president and CEO of the Pacific Salmon Foundation, one of the partners constituting the Strategic Salmon Health Initiative (SSHI), of which the study is part of.
Riddell added that these findings add to the existing concerns about the potential impacts of open net salmon farming on wild Pacific salmon off the coast of BC.
Before this study, there was a debate as to whether PRV posed a risk to migratory salmon, especially in British Columbia where commercially important wild Pacific salmon are in decline.
PRV was previously known to cause HSMI - a significant cause of mortality and economic loss in the salmon-farming industry - in Atlantic salmon. HSMI has been reported in Norway, UK/Scotland, Chile and British Columbia.
But until the study findings, the PRV-1 strain that causes HSMI, and the only strain detected in BC, had not been shown to be directly affiliated with disease in Pacific salmon.
"Our study used novel molecular tools to show that PRV-1 was intimately involved in the development of jaundice/anemia in Chinook salmon", said Dr. Kristi Miller-Saunders, lead scientist in the SSHI and who works for Fisheries and Oceans Canada, another SSHI partner.
"The study also reveals a difference in PRV-1 sensitivity between species that could easily explain why the virus causes inflammation in Atlantic salmon and cell death in Chinook salmon. Based on the results, we concluded that Chinook salmon may be at more than a minimal risk of disease from exposure to PRV occurring on salmon farms", she added.