The problem from my perspective is that mere presence of piscine reovirus (PRV) is getting kind of blown out of proportion. Personally, I have no issue with someone private trying to look into things like this. For instance, researchers from BC universities (i.e. UBC) are quite active in the Fraser watershed doing salmon research. I know a few of them quite well and they are very competent people who very professional in their approach. They collaborate with DFO and ENGOs like the Pacific Salmon Foundation and do good work which is transparent and defensible. In contrast, those private individuals in the anti-fish farm camp (i.e. people like Don Staniford) looking for viruses are the complete opposite, in my opinion.
The mere presence of PRV does not prove anything, but what I do have a problem with are the conclusions made afterwards which are more speculation at this point than fact. Reoviruses get their name from the respiratory and enteric orphans – meaning that they were commonly associated with the respiratory and digestive system, but not with disease. The “O” in reovirus stands for orphan – meaning they are viruses without a disease.
Suspicions of HSMI are based on one study from Palacios et al 2010 which found a link between PVR and HSMI. Soon after Ms Morton found PRV in farmed salmon purchased in stores and started calling the PRV the “heart and skeletal muscle inflammation virus” which is misleading and should have been balanced with some objectivity considering the evidence gathered to date. For instance, if you look at local evidence you will find something completely different. As I stated before on this forum, believe it or not, most healthy broiler chickens (80-90%) from the Fraser Valley would be positive for reovirus. Recent testing of 150 healthy, wild pink salmon on our coast showed no positive PCR test results the virus and no suspicious heart lesions (Saksida et al. 2012). In 2010, Dr. Gary Marty found that 75% of the farmed salmon he tested were positive for PRV, but found no signs of disease.
It is important to note that Ms Morton did not find HSMI in her samples and neither did Rick Routledge with the cutthroat trout in Cultus Lake. Just because you find a virus in the host does not necessarily mean that the host is suffering from a disease. There is a difference between a virus and a disease. You need to examine the tissues – preferably someone who is fish pathologist. Neither Morton nor Routledge did this necessary follow-up to confirm their suspicions. Neither Morton nor Routledge are fish pathologists or virologists. Viruses are actually part of a larger equation which can involve environmental conditions, individual fitness, physiological stress, etc. Fish farm critics like Morton and Staniford use “viruses” and “diseases” interchangeably - misinforming the public as a result. Thus, a positive PCR test for PRV does not mean that the host has HSMI. Morton’s findings in market sized fish may not have been in vain totally because they are good evidence that the virus was not the cause of disease in those fish. HSMI primarily affects juvenile fish. Think about…if most of them had this deadly virus they would not have survived past the juvenile stage.
Palacios, G., Lovoll, M., Tengs, T., Hornig, M., Hutchison, S., Hui, J., Kongtorp, R.T., Savji, N., Bussetti, A.V., Solovyov, A., Kristoffersen, A.B., Celone, C., Street, C., Trifonov, V., Hirschberg, D.L., Rabadan, R., Egholm, M., Rimstad, E. & Lipkin, W.I. 2010. Heart and skeletal muscle inflammation of farmed salmon is associated with infection with a novel reovirus. PloS One 5(7), e11487.
Saksida, S.M., G.D. Marty, S. St-Hilaire, S.R.M. Jones, H.A. Manchester, C.L. Diamond, and J. Bidulka. 2012. Parasites and hepatic lesions among pink salmon, Oncorhynchus gorbuscha (Walbaum), during early seawater residence. J. Fish Dis. 35:137-151.