Strengthened knowledge about the Spironucleus parasite

The following has been translated and edited from the Norwegian Seafood Research Fund (FHF) about the Spironucleaus parasite. Review the original text.  

Strengthened knowledge about the Spironucleus parasite

FHF (the Norwegian Seafood Research Fund) has released findings from the SpiroFri project, revealing strengthened knowledge about the Spironucleus parasite.  

The FHF-funded SpiroFree project was initiated following several outbreaks of spironucleosis at fish farms in Northern Norway in 2023, which cost the industry over a billion Norwegian kroner (around £75.8 million).  

The Institute of Marine Research (IMR) acted as the project lead, and the team included Nofima, the Norwegian Veterinary Institute, and Grieg Seafood, among others.  

The benefits of the research are immediate: In addition to a set of technical recommendations, new and more accurate qPCR methods (molecular tests) have been developed, which can distinguish between different species of Spironucleus. This will make it easier for fish farmers to monitor infection pressure in both intake water and fish stocks.  

Research shows that the parasite does not survive well in clean freshwater or 100% seawater, but prefers low-temperature brackish water with around 10ppt (parts per thousand) salinity. This provides the industry with concrete evidence for risk assessment in connection with the transport of fish between sites.   

Trials with UV disinfection show that ‘medium pressure’ UV lamps are decidedly more effective against S. salmonicida than ‘low pressure’ lamps. The results show that the current requirements for UV treatment are not sufficient for treatment against S. salmonicida.   

One infection trial showed that the parasite did not become established in RAS systems. The infection trials document that salmon develop the disease, while trout and char can act as infection carriers without developing serious disease.   

However, lumpfish are vulnerable, displaying rapid disease development and high mortality, which means they are considered unsuitable for facilities where the salmon may have spironucleosis.   

Find out more here. This page include a link to download  a lengthier final report (in Norwegian).   

If you have any questions about FHF funding calls (for which Scottish applicants may be eligible) or if you want to find out more about their current research priorities, contact the SAIC team, who will be happy to help.