CMS is a viral disease that causes inflammation of the fish's heart.

Researchers plan simpler, faster salmon heart disease test

An early warning system to alert salmon farmers to cardiomyopathy syndrome (CMS) in their fish in under three hours is being developed by a Scottish research group.

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CMS is one of the biggest causes of losses to the Norwegian salmon industry and an increasing problem for Scotland’s salmon farmers.

Although the triggers of CMS are not fully understood, it is known to be caused by piscine myocarditis virus (PMCV) and can lead to heart failure in apparently healthy fish - resulting in significant stock losses.

Cardiac markers

The project consortium includes Cooke Aquaculture, the University of Edinburgh, Life Diagnostics, Benchmark Genetics, Moredun Research Institute and the Scottish Aquaculture Innovation Centre (SAIC).

The consortium aims to identify specific cardiac markers in the blood of fish, which can be used to detect CMS prior to signs of clinical disease, said SAIC in a press release. In both human and veterinary medicine, cardiac issues are already detected via biomarkers, measured using commercial testing kits. 

Although there is no vaccine or treatment for CMS, a warning system would enable salmon producers to better manage the disease and minimise its economic impact. In its early stages, CMS is difficult to detect, and fish can be infected for some time before symptoms appear.

On-site testing

The team will identify new cardiac markers to specifically detect heart disease in salmon and apply these to diagnostic techniques currently used in human and veterinary diagnostics. This will include tests adapted for on-site farm testing with the ability to provide results in less than three hours.

The biomarkers could also help to differentiate between CMS and other salmon heart diseases, such as pancreas disease and heart and skeletal muscle inflammation. 

In addition, the project outcomes could also contribute to future genetic breeding programmes against CMS, using the methodologies developed in this project to select fish that show physiological resistance to the disease.  

An insidious disease

Dr Andrei Bordeianu, veterinarian with Cooke Aquaculture Scotland, said: “Piscine myocarditis virus is an insidious disease spreading unnoticed on farms until a tipping point is reached and it is too late to act once CMS is confirmed.

“Monitoring the spread of disease in cages requires laborious, expensive sampling to achieve only limited results. Investigating new possibilities to measure the virus’ impact on large sections of our salmon population is something that will bring invaluable support to health monitoring on our farms and will help us to evaluate the mitigation measures we currently undertake.”

Dr Polly Douglas, aquaculture innovation manager at SAIC, added that finding simple, cost effective and non-lethal diagnostic methods that can help to reduce the impact of disease in aquaculture was crucial to addressing the objectives of the Scottish Government’s 10-year Farmed Fish Health Framework.