they still talk about PRv not causing HMSI.
"The PRV strain present in indigenous Pacific salmon in the PNW, historically and experimentally, appears to be relatively benign and unable to produce significant disease or HSMI in native salmonids.
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ENGO pundits are once again using typical distraction tactics but its okay i'll post it again so they can read it over
https://www.dnr.wa.gov/sites/default/files/publications/PRV whitepaper revised Sept 2017.pdf?3c0h5&9laxp
PISCINE ORTHOREOVIRUS (PRV) IN THE PACIFIC NORTHWEST APPEARS TO BE OF LOW RISK TO WILD PACIFIC SALMONIDS
This summary report contains the most current information available on PRV risk to wild Pacific salmonids contributed by expert fish health practitioners and researchers in the Pacific Northwest Prepared By The Pacific Northwest Fish Health Protection Committee By T.R. Meyers Alaska Department of Fish and Game Juneau Fish Pathology Laboratory
Summary Conclusion Based on Available Data: The ubiquitous nature of piscine orthoreovirus (PRV), its apparent historic presence in wild Pacific salmonid stocks in the Pacific Northwest and the lack of clear association with disease in Pacific salmonids suggest the virus poses a low risk to wild species of Pacific salmonids.
Molecular testing of archived fish tissues in BC has shown that PRV was present in wild and farmed salmonids since 1987 and may have been present as early as 1977 in one sample from steelhead trout (19)
Why PRV in the PNW is of low risk regarding HSMI in wild Pacific Salmonids
1. The disease “heart and skeletal muscle inflammation” (HSMI) has not been reported in wild salmon populations in Norway or elsewhere and appears to only be a threat to farmed fish
2. While PRV causes HSMI in farmed Norwegian Atlantic salmon, high levels of PRV genetic material have been detected in asymptomatic wild and cultured salmonids with no evidence of HSMI disease
3. Histopathological lesions of HSMI were recently described as statistically correlated with the presence of PRV at one Atlantic salmon farm in British Columbia, Canada (BC) while other studies have detected the presence of PRV genetic material in wild and cultured Chinook, coho and pink salmon and steelhead trout from Washington State, BC and Alaska where years of surveillance have reported no presence of HSMI
4. Molecular testing of archived fish tissues in BC has shown that PRV was present in asymptomatic wild and farmed Pacific salmon since 1987 and may have been present as early as 1977 before Atlantic salmon were imported for aquaculture
5. HSMI has not been reported in Pacific salmon or steelhead in North America to date
6. Laboratory studies with Chinook and sockeye salmon have demonstrated that PRV is infectious and will persist for quite some time but does not cause fish mortality, HSMI, or any other apparent disease
7. Development of HSMI and HSMI-like diseases of farmed salmonids (Atlantic and coho salmon; rainbow trout) infected by PRV may be a result of different viral strains, host specific antiviral responses and environmental stressors that do not appear to be present or active for indigenous salmon on the Pacific Coast
8. The presence of PRV genetic material in Pacific salmon tissues is not sufficient evidence for HSMI disease
Laboratory challenges of Chinook, sockeye and Atlantic salmon injected with PRV infected material from Pacific Northwest salmonids resulted in no significant mortality or clinical disease (21, 22). A second study of Chinook salmon also injected with PRV positive material from Pacific Northwest salmonids resulted in virus replication with transient cytoplasmic inclusion bodies in red blood cells causing no reduction in hematocrits and no fish mortality (23). Similar challenge studies in rainbow trout (23) also resulted in no direct mortality following injection with PRV infectious material.
These experimental studies suggest PRV in the Pacific Northwest is of low virulence for rainbow trout, Chinook and sockeye salmon.
The PRV strain present in indigenous Pacific salmon in the PNW, historically and experimentally, appears to be relatively benign and unable to produce significant disease or HSMI in native salmonids.
