PhD defence on prevalence and diagnostic of PRV-3 virus in rainbow trout

The virus Piscine orthoreovirus (PRV) has been associated with disease outbreaks in salmonid farming worldwide in recent years. In Denmark, severe outbreaks linked to the PRV-3 genotype were first observed in two separate rainbow trout recirculating aquaculture farms in 2017.

During her PhD study at DTU Aqua, Juliane Sørensen has developed and tested a new diagnostic method to detect PRV-3 and other pathogens in farmed fish. In addition, she has investigated the distribution of PRV-3 in Denmark and various aspects of the virus.

She concludes that PRV-3 is widespread in Danish aquaculture, and that the virus has been present since at least 1995. The spread likely occurred through the transport of live fish between farms.

The outbreaks in Denmark in 2017 occurred during the winter. Therefore, Juliane Sørensen has investigated the relationship between low water temperatures and the virus. She concludes that there is more PRV-3 virus when the water temperature is low, and that the pathologic changes in the fish are more severe. However, low water temperatures alone are not enough to trigger mortality under experimental conditions.

Juliane Sørensen's field studies show that infections with several pathogens often occur in rainbow trout in recirculating systems (RAS). Using the diagnostic method developed as part of the PhD project (high-throughput qPCR), Juliane and her colleagues found PRV-3 together with the putative gill pathogen Candidatus Branchiomonas cysticola at high levels during a disease outbreak. In this case, they assessed that stress associated with moving the fish may have had a significant role in the outbreak.

About the defence

Juliane Sørensen will defend her PhD thesis “Mitigating the impact of PRV-3 infection in rainbow trout production by high-throughput diagnostic platforms” on Friday, 1 March 2024, at 13:15. The defence can be followed online or at DTU, Anker Engelunds Vej, 2800 Kgs. Lyngby, building 306, auditorium 32.

Examiners

• Professor Peter M. H. Heegaard, DTU Health Tech (chair)
• Senior Researcher Carlo Lazado, Nofima, Norway
• Professor Øystein Evensen, Norwegian University of Life Sciences, Norway

Chair at the defence

• Senior Researcher Tommy Norin, DTU Aqua

Supervisors

• Principal supervisor: Senior Researcher Niccolò Vendramin, DTU Aqua
• Co-supervisor: Senior Researcher Kerstin Skovgaard, DTU Bioengineering

Learn more

A copy of the thesis is available for reading at DTU Aqua. Please contact PhD Coordinator Susan Zumbach Johannesen, szjo@aqua.dtu.dk