Cardiomyopathy syndrome in farmed Atlantic salmon Salmo salar: occurrence and direct financial losses for Norwegian aquaculture

Cardiomyopathy syndrome (CMS) is a disease of unknown aetiology, having significant economic impact as it primarily affects large, farmed Atlantic salmon Salmo salar L. in seawater, close to harvest. In the present study, we have demonstrated that CMS is a transmissible disease under experimental conditions. Histopathological lesions consistent with CMS were induced in Atlantic salmon post-smolts after injection of tissue homogenate from farmed fish diagnosed with CMS. Six weeks post-injection (p.i.), experimental fish started developing focal to multi-focal lesions in the atrial endo-and myocardium, with subsequent progression to the ventricle. This proceeded into severe endocarditis and subsequent myocarditis with mononuclear cell infiltration of the atrium and, to a lesser degree, the spongy layer of the ventricle. These lesions were consistent with histopathological findings in field outbreaks of CMS. From Week 33 p.i., lesions also appeared in the compact myocardium, with focal epicarditis adjacent to focal myocardial lesions. In conclusion, these results indicate that CMS has an infectious aetiology and should be treated as a potentially contagious disease.

Section: Discussionsupporting

confidence: 51%

Section: Discussionmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 99%

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Experimental transmission of cardiomyopathy syndrome (CMS) in Atlantic salmon Salmo salar

Fritsvold¹,

Kongtorp²,

Taksdal³

et al. 2009

“…CMS is most commonly diagnosed during the late sea-water phase in farmed salmon and is thus a disease causing considerable losses for the affected farms and the industry (Brun et al 2003). The clinical features of CMS vary from acute death without prior clinical signs to elevated mortality with nonspecific signs such as impaired or abnormal swimming behaviour.…”

Section: Introductionmentioning

confidence: 99%

Piscine myocarditis virus (PMCV) in wild Atlantic salmon Salmo salar

Garseth

Biering²,

Tengs³

2012

Cardiomyopathy syndrome (CMS) is a severe cardiac disease of sea-farmed Atlantic salmon Salmo salar L., but CMS-like lesions have also been found in wild Atlantic salmon. In 2010 a double-stranded RNA virus of the Totiviridae family, provisionally named piscine myocarditis virus (PMCV), was described as the causative agent of CMS. In the present paper we report the first detection of PMCV in wild Atlantic salmon. The study is based on screening of 797 wild Atlantic salmon by real-time RT-PCR. The samples were collected from 35 different rivers along the coast of Norway, and all individuals included in the study were classified as wild, based on visual appearance and scale reading. Two samples tested positive during PCR analysis, and the results were confirmed by sequencing. KEY WORDS: Piscine myocarditis virus · Wild Atlantic salmon · PCR · CMS · Disease interactionResale or republication not permitted without written consent of the publisher OPEN PEN

“…Cardiomyopathy syndrome (CMS) is an economically important disease of adult Atlantic salmon Salmo salar in seawater (Brun et al 2003). This enigmatic syndrome currently accounts for significant losses through disease in terms of tonnage (S. Murray pers.…”

Section: Introductionmentioning

confidence: 99%

Comparative experimental transmission of cardiomyopathy syndrome (CMS) in Atlantic salmon Salmo salar

Bruno

Noguera²

2009

Cardiomyopathy syndrome (CMS) has been recorded in wild and farmed Atlantic salmon Salmo salar. Characteristic heart lesions primarily involving the myocardium are reported in natural outbreaks with associated mortality. To date, no experimental trials have reproduced these lesions in the laboratory. The present study reports on the first successful experimental transmission of CMS in Atlantic salmon in Scotland, with full development of the histological lesions that are described for the syndrome. Tissue homogenates of CMS-infected fish indicative of mild and severe lesions from Scottish and Norwegian natural outbreaks, respectively, were injected into naïve fish, and both induced heart lesions consistent with CMS. Lesion development was earlier and progression faster in the fish group receiving the Norwegian homogenate, but equivalent in both groups by the end time point of the experiment. The study demonstrated that the reported condition for both countries is identical, as evaluated through light microscopy, and that tissue homogenates from either mild or severely affected fish contain the transmissible agent. KEY WORDS: Cardiomyopathy syndrome · Atlantic salmon · TransmissionResale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESS