Thursday, 6 October 2016

PRV Present in 80% of Farmed Salmon - GD Marty, Updated Jan 10, 2017

This is the document where GD Marty, provincial fish pathologist, notes that 80% of farmed fish in BC have PRV virus. While he says HSMI has not been proven to be caused by PRV, I'd fall off my chair if it turned out to be something else.

What is alarming, is the cavalier attitude of 'Problem, what problem?'


"1. In BC, PRV is common in farmed Atlantic salmon and farmed Pacific salmon, but HSMI does not occur in BC. 
2. A PCR- positive test result for piscine reovirus does not mean that the fish have the disease HSMI; it only means that a segment of the virus (PRV) was detected in the fish.
3. Diagnosing the disease HSMI requires histopathology.
4. In 2010 the BC Ministry of Agriculture developed two PCR tests for PRV. Test validation revealed that piscine reovirus occurred in about 80% offarmed Atlantic salmon with and without unexplained heart disease. This is evidence that PRV is not the cause of unexplained heart disease."

And this:

"The samples were from 76 government audits of recently dead fish (n = 402) on the salmon farms and 137 fish that had been submitted directly from farm veterinarians, most of which were for health screening before transfer. The PRV prevalence was about 80% in all three groups of interest: audits with fish that died of unexplained heart disease (4 of 5 audits), audits with no fish that died of unexplained heart disease (56 of 71 audits), and direct submissions from salmon farms, none of which died of unexplained heart disease. We concluded that PRV is common among farmed Atlantic salmon in British Columbia, but PRV is not associated with any cause of mortality, including unexplained heart disease (Marty and Bidulka 2013)."

Hmm. On the edge of my seat, waiting to hit the floor.

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