September 26, 2018

Canada launches PRV science review

PRV Assessment will support decision making on sustainable aquaculture and aquatic animal health in Canada

The Department of Fisheries and Oceans has launched a science review to assess risks associated with Piscine Orthoreovirus, also known as Piscine Reovirus, (PRV) transfer from Atlantic salmon farms.

The results of the assessment will support decision making on sustainable aquaculture and aquatic animal health in Canada, including in the Discovery Islands and Broughton Archipelago, said Jonathan Wilkinson, Minister for Fisheries, Oceans and the Canadian Coast Guard (pictured)

The minister announced that the review will include domestic and international scientific experts including those from government, academia, Indigenous communities, ENGOs, and industry.

The review will be generated through DFO’s Canadian Science Advisory Secretariat and a final report will be publicly available in early 2019.

“Our government is committed to using best available science to protect wild Pacific salmon, including Fraser River sockeye…this scientific assessment will be undertaken by a diverse group of independent experts, and will inform thoughtful, science-based decisions on sustainable aquaculture.”

Dr. Jim Powell, the CEO of BC Centre for Aquatic Health Sciences (BC CAHS) welcomed the review saying it will be a touchstone for future analysis on the subject.

“Given the experts involved, the review will be super valuable and something that you can really rely on,” he told SeaWestNews.

Piscine orthoreovirus or PRV predates fish farms in BC and has long been present in wild salmon in Pacific Northwest waters, said Dr. Powell.

Kyle Garver a research scientist for Fisheries and Oceans Canada and a PRV expert had also concluded earlier this year that PRV has been ubiquitous in the Pacific Northwest for many decades, and that it isn’t linked to any fish disease or mortality.

The bottom line consensus from the aquaculture scientific community so far is that PRV is common but the fish on BC salmon farms are not sick. Much like humans, it’s normal that fish are naturally exposed to numerous viruses every day without adverse effect.

Question and Answer: Piscine Reovirus

Q: What is PRV?

Piscine reovirus is a virus that can infect Atlantic and Pacific salmonids. Reoviruses get their name because many are respiratory and enteric orphans. They are called “orphans” because many are viruses without an associated disease.

Q: Is Piscine reovirus found in BC?

Yes. Research published in 2014 suggests PRV has long been present in wild salmon in Pacific Northwest waters.

Q: What impact does PRV have on salmon?

PRV has been detected in healthy fish in healthy populations, showing that its presence does not mean disease occurs.

Q: But isn’t a virus a disease?

No. Not all germs in our environment cause disease. There are millions of viruses in every drop of seawater. Viruses are carried by all living things and most never cause disease. Other reoviruses have been found for decades in wild fish and never associated with disease. In British Columbia, there is no link between the presence of PRV and any disease.

Q: Do salmon farmers test for PRV ?

Yes. BC salmon farmers provided samples for the 2014 scientific study that documents PRV in BC and Alaska salmon without associated disease. BC salmon farmers are providing samples for other scientific studies that are underway. This is being done even though Fisheries and Oceans Canada (DFO) and the Canadian Food Inspection Agency (CFIA) do not have PRV on the list of reportable diseases/pathogens.

Q: What about the suggested link between Piscine reovirus and heart and skeletal muscle inflammation (HSMI)?

That link refers only to Norwegian strains of PRV in farmed Atlantic salmon. HSMI is common in Norway, but HSMI has never been identified in any wild fish in the Pacific Northwest. Viruses with the same name often occur as different types in different parts of the world. Some types might cause disease whereas others do not. Piscine reovirus is a good example.

Q: Is there any human health risk associated with Piscine reovirus?

No. Viruses found in salmon (including Piscine reovirus) are not a risk to human health.