Lawsuit filed against Minister of Fisheries

& Marine Harvest Canada

application filed in Federal Court
Adobe Acrobat document [1.8 MB]

Published Science on the Piscine Reovirus & HSMI

Piscine Reovirus – what does the scientific literature say


1985 ~ 30 million Atlantic salmon eggs began entering British Columbia for the purposes of salmon farming


11999 a disease syndrome was first observed in farmed Atlantic salmon in Norway – cause unknown, at some point it is named Heart and Skeletal Muscle Inflammation, HSMI.


12004 team of 5 Norwegian scientists find HSMI can spread fish to fish by injecting a homogenate of an infected fish into a naïve fish and by cohabitation. Thus they determined the “syndrome” is an infectious disease. A viral aetiology was “strongly suggested.” The number of reported outbreaks was increasing [as recorded by the National Veterinary Inst. of Norway, 2003] In 2002, 41 farms were diagnosed with HSMI. Symptoms of the disease occur 5-9 months after transfer. (Kongtorp et al. 2004)


22005 HSMI appears in Scotland. Afflicted fish are described as “lethargic” “stacking up and holding station in the current,” as opposed to normal farm salmon swimming patterns of continuous circling the pen. This paper reports “pale lethargic fish accumulating on the net floor, sometimes lying on their sides,” and “soft, flabby” hearts. “There is little doubt that fish with lesions as severe as these would be reluctant to move and would be suffering clinically from a failing cardiovascular system.” Biosecurity helped limit the spread to adjacent sites. (Ferguson et al. 2005) (this study includes Norwegian authors from the 2004 paper).


32010 Piscine reovirus is discovered and proposed as the causative agent of HSMI. There are now 419 farms infected with HSMI in Norway. All salmon with HSMI have the virus. PRV cannot be cultured. PRV also found in fish not showing HSMI, PRV in low amounts in wild salmon. Compares similarities between salmon and poultry production as conducive to transmission and reduced resistance to infectious agents. “it is urgent that measures be taken to control PRV … due to the potential for transmission to wild salmon populations.” (Palacios et al 2010)


4In popularized version of the above paper one of the authors states: If the potential hosts are in close proximity, it goes through them like wildfire,” said Lipkin.


52010 fish with HSMI seem to be able to recover with time.” This could be part of the reason fish with PRV can appear “healthy.” States HSMI has not been found in freshwater, but this refers to the disease, not the virus, and then says the disease is normally observed 5-9 months after transfer [to saltwater]. Also compares chicken and salmon farming as similar both infected with reoviruses that are causing economy damage. In the case of the Dalrymple fish, the virus was confirmed in the fish in freshwater, and from this paper is not surprising if they did not appear to have the disease. (Løvoll et al. 2010)


62012 calls HSMI an “emerging disease,” “widespread and economically important.” “Our results confirm the association between PRV and HSMI and strengthen the hypothesis of PRV being the causative agent of HSMI.” While only 20% of afflicted farm salmon might die, morbidity includes “most” fish (so nearly all the fish show signs of the disease at some point, but can recover). “PRV is almost ubiquitously present in Atlantic salmon marine farms,” amount of virus is lower in fish not showing signs of the disease. Reports the reoviruses in chickens also cause heart problems, but are “generally benign” in humans. Notes that farm salmon do recover. Suggests a secondary factor, such as stress is required in addition to PRV to cause the disease, HSMI. The paper suggests that while PRV may be common to all farm salmon, that possible a more virulent strain is appearing in the feedlot environment of salmon farms. (Finstad et al 2012)


72012 “… it would be premature to conclude about the effects on wild fish at the present time” [and even less is known about the impact on wild Pacific salmon] (Biering et al 2012)


82012 Marine Harvest 2012 Annual Report [only partially printed out, bad alignment issues] lists HSMI as the #2 largest cause of mortality [death] in their fish see screen shots below.


92013 Calls HSMI “severe” disease PRV detected in 55.2% escaped Atlantics, 24% of hatchery Atlantics and 13.4% of wild Atlantics in Norway. 162 infected farms in 2007. Few studies on spread of viruses from farm salmon to wild, “generally acknowledged that aquaculture can influence diseases in wild fish populations… or by introducing pathogens into new geographical areas.” In two Norwegian rivers PRV detected in escaped and hatchery Atlantics, but not in wild Atlantics. They note “limited knowledge about the occurrence of PRV in farmed salmon,” and so could not confidently correlate prevalence in the wild salmon to farm infection of PRV. The paper notes if wild salmon show signs of the disease they would be “less capable of returning to rivers,” and all these samples were from the rivers. In general, diseased wild fish are difficult to sample because they display abnormal behaviour or reduced swimming capacity and will be removed by predators or otherwise disappear in the mass of water.” They note it is important to screen wild fish for PRV to shed light on any association with decreasing wild populations.   (Garseth et al 2013)


102013 (in prep.) First report of PRV outside of Norway. The strain sequenced in BC is of Norwegian genotype and diverged from Norwegian sub-genotype Ia in 2006 ± 1. The virus has also been detected in Atlantic herring, mackerel and smelt. (I am co-author and samples include BC farm salmon from supermarkets)


112011 - Aquaculture is the key driver for the introduction of non-native species. Most farming systems allow pathogen exchange between farmed and wild populations which underpins host-switching. Subsequently movements of animals between farms may result in the spread of newly emerged diseases.” Aquaculture and the ornamental aquatic animal trade are the key drivers for the introduction of non-native aquatic animal species…. Without improved risk mitigation (quarantine, introduction of fertilized eggs) disease emergence as a result of non-native species introduction will continue with potentially serious consequences for wild aquatic animal populations” Note this paper using the term “parasite” to mean virus (Peeler et al 2011).


122008 In this year Gary Marty, provincial farm salmon health vet reports a pattern of heart inflammation in BC farm salmon that has “has also been described with Hearth and Skeletal Muscle Inflammation in Atlantic salmon reared in Europe.” It was unknown at that time that PRV was associated with HSMI, and there was no test for HSMI, other than the diagnostics that Dr. Marty did, so technically this may be diagnosis of HSMI – need to get expert opinion on this.


13 2012 DFO denies presence of PRV, fish farm industry denies presence of HSMI, Provincial vet, Gary Marty says it is common in farm salmon, but “wild fish are not infected with PRV


14 2012 Gary Marty co-publishes paper reporting 200 juvenile salmon collected in Broughton in 2008 do not have PRV. This is highly significant because I found it to be so prevalent in the same age class and species in the same region in 2012. While this is an extremely scant “trend” it is all we have and it supports the scientific literature warning that this virus spreads fast and easily… like “wildfire.”


15, 16 2012 juvenile and adult salmon sampled in Broughton in 2012 test positive for PRV at the Kibenge Lab at the Atlantic Veterinary College


Facts Important to this case:


The disease HSMI was known from 1999 -2010, but there was no way to screen incoming Atlantic salmon eggs for this, because the causative agent was unknown.


It has spread rapidly through Norwegian farms


1999 – 1st noticed1

2002 – 41 farms infected1

2007 – 162 farms infected9

2010 – 419 farms infected3


The symptoms of the disease occur 5-9 months after seawater transfer5 – so smolts leaving the hatchery would not appear sick.


Fish with the disease (not just the virus) are seen lying on their sides on the bottom of the net cage while still alive.2


Biosecurity is important to help limit the spread to adjacent sites2


At a time when humans are being encouraged to eat fish to help combat … coronary disease, it seems somewhat ironic the heart disease seems to be such a problem in the fish themselves.”2


Urgent that measure be taken to control PRV to prevent transmission to wild salmon populations.3


Spreads like “wildfire4


Farm fish with PRV may recover, this does not refer to wild salmon, which would be extremely vulnerable to predation if found lying on their side, on the seafloor, as described for farm salmon fighting HSMI (floor of the pen in this case).5


PRV widespread, this paper suggest higher virulence in some strains of PRV may be causing disease, whereas the lower virulence may not – just a theory.6


Premature to make any conclusions that this virus has more/less impact on wild salmon than on farm salmon – nothing can be said about impact on health of wild salmon at this point.7


HSMI is the #2 killer of Marine Harvest farm salmon worldwide and BC is where #2 greatest farm salmon losses are occurring for Marine Harvest (they show a map and there are no MH farms listed for eastern Canada, so all numbers reporting on Canada, are BC)8


HSMI referred to as a “severe” disease. Found in free-ranging Atlantics in Norway, but at much higher levels in escaped farm salmon and hatchery salmon, than the truly wild Atlantics. 9


PRV sequence from BC matches PRV sequence from Norway, the virus appears to be Norwegian and to have entered BC in 2006 ± 110


HSMI-type lesions were found in BC farm salmon, prior to discovery of PRV. Since the only diagnostics available for HSMI in 2008 was detection of the lesions, this report by Dr. Marty might be seen as reporting of the disease.11


Aquaculture can import disease with potentially serious negative consequence to wild species12


200 Juvenile salmon collected in Broughton Archipelago in 2008 by DFO test negative for PRV, testing done by Dr. Gary Marty.14


BC wild juvenile and adult salmon test positive for PRV in Broughton Archipelago in 2012 15, 16





1Kongtorp, R.T., Kjerstad, A., Taksdal, T., Guttvik, A., Falk, K. 2004 Heart and Skeletal muscle inflammation in Atlantic salmon Salmo salar L.: a new infectious disease. Journal of Fish Diseases 27, 351-358.


2Ferguson, H.W., Kongtorp, R.T., Taksdal, T., Graham, D., Falk, K. 2005 An outbreak of disease resembling heart and skeletal muscle inflammation in Scottish farmed salmon, Salmo salar L., with observation on myocardial regeneration. Journal of Fish Disease 28, 119-123.

3Palacios G, Lovoll M, Tengs T, Hornig M, Hutchison S, Hui J, Kongtorp RT, Savji N, Bussetti AV, Solovyov A, Kristoffersen AB, Celone C, Street C, Trifonov V, Hirschberg DL, Rabadan R, Egholm M, Rimstad E, Lipkin WI: 2010 Heart and skeletal muscle inflammation of farmed salmon is associated with infection with a novel reovirus. PLoS One 2010, 5:e11487.



5Løvoll, M., Wiik-Nielsen, J., Søren, G., Wiik-Nielsen, C. R., Kristofferson, A.B., Faller, R., Poppe, T., Jung, J., Pedamallu, C., S., Nederbragt, A. J., Meyerson, M., Rimstad, E., Tengs, T. 2010. A novel totovirus and piscine reovirus (PRV) in Atlantic salmon (Salmo salar) with cardiomyopathy syndrome (CMS). Virology Journal. 7: 309


6Finstad, Ø. W., K. Fal, M. LØvol, E. Øystein, E. Rimstad. 2012 Immunohistochemical detection of piscine reovirus (PRV) in hearts of Atlantic salmon coincide with the course of heart and skeletal muscle inflammation (HSMI). Veterinary Research, 43:27.

7Biering, E., Madhun, S. A., Isachsen, C. H., Omdal, L. M., Einen, A. C. B., Garseth, Å. H., Bjørn, P. A., Nilsen, R., Karlsbakk, E. 2012. Annual report on health monitoring of wild anadromous salmonids in Norway. Institute of Marine Research 6, 2013

8Marine Harvest 2012 Annual Report

9Garseth ÅH, Fritsvold C, Opheim M, Skjerve E, Biering E: Piscine reovirus (PRV) in wild Atlantic salmon, Salmo salar L., and sea-trout, Salmo trutta L., in Norway. J Fish Dis 2012, doi:10.1111/j.1365-2761.2012.01450.x

10Kibenge, M. J. T., Iwamoto, T., Wang, Y., Morton, A., Godoy, G., Kibenge, S. B. (under review) Whole-genome analysis of piscine reovirus (PRV) shows PRV represents a new genus in family Reoviridae and its genome segment S1 sequences group it into two separate sub-genotypes

11Gary Marty 2008 Final Report AHC Case 08-3362 to Mainstream Canada


12Peeler E.J., Oidtmann B.C., Midtlyng P.J., Miossec L. & Gozlan R.E. (2011) Non-native aquatic animals introductions have driven disease emergence in Europe. Biological Invasions 13, 1291–1303.


13 FIS article April 17, 2012, Disease in fish claimed wrong by salmon farmers


14 Saksida, S.M., Marty, G.D., Jones, S.R., Manchester, C.L., Diamond, C.L., Bidulka, J., St-Hilaire, S. 2012. Parasites and hepatic lesions among pink salmon, Oncorhynchus gorbuscha (Walbaum), during early seawater residence. Journal of Fish Diseases. 35 137-151


15 August 9, 2012 lab report from Atlantic Veterinary College


16 September 28, 2012 lab report from Atlantic Veterinary College

Support this Work

We are just 2 women with little overhead & big projects. Your donation helps to pay for lab bills, research costs, video production and awareness raising campaigns.

Donate Here

Follow us on FaceBook

Print Print | Sitemap
© Twyla Roscovich