Øystein Evensen got his degree in veterinary medicine from the Norwegian School of Veterinary Science in 1984 and his PhD in pathology in 1987. He is currently professor in in aquatic medicine at the Norwegian University of Life Sciences (NMBU), Faculty of Veterinary Medicine, and head of the research group "Host-pathogen interactions in infection and immunity".
Major research interests concern viral and bacterial diseases of farmed salmon, mechanisms of infection, and vaccine development. A special area of interest over the last years has been cardiomyopathy syndrome of Atlantic salmon. The research group also works on immunoprophylactic principles against sea lice infection in Atlantic salmon. To study infection mechanisms and pathogenic events of disease (pathogenesis) related mainly to viral infections, the research group also uses model fish. Here the group has used reverse genetics made viruses to understand virulence mechanisms and virulence factors that the virus employs to circumvent antiviral responses of the host.
In addition to research linked to Norwegian salmon production, Evensen's research group is involved in research and capacity building in Africa (Zambia, Tanzania, Kenya and Uganda), with focus on tilapia lake virus, diagnostic methods and pathogenesis studies.