Infectious salmon anaemia virus (ISAV): Characterization of functional virulence markers

The applicant, Der Falk, has played a key role for ISA research since he was part of the team that made the first isolation of the ISAV in 1995. Since then he has more than 40 publications in international journals on ISA and has been frequently sited. He is now a designated OIE expert on ISA. Dr. Falk plan to work for 12 months at the lab of Dr. Sergio Marshall at the Pontifical Catholic University of Valparaís, Chile and who is also both national and international reference laboratory for ISA, thus this project will provide an opportunity to address and explore common challenges related to ISA research and control. A major challenge associated with ISA control is questions related to risk and drivers for the transition of non-virulent HPR0 ISAV to virulent HPR-deleted ISAV. These questions have become very important in relation to international Atlantic salmon trade as both virus types have been made notifiable by the OIE. To address and solve this key question, we need knowledge about ISAV virulence factors which are currently insufficient both with regard to genetic and functional features. In addition, more knowledge concerning ISAV functional virulence factors will also provide an important foundation for development of new targeted vaccines against ISAV based on modern molecular technology. The current project proposal includes two work packages. In the first, the significance of the virus receptor destroying enzyme (RDE) for virulence will be explored through functional studies. The potential importance of this factor is underlined by the fact that the most used anti influenza drugs, Tamiflu and Relenza, are RDE inhibitors. In the second work package, a selection of HPR-del ISAV will be examined with respect to variation in functional activities potentially associated with virulence. Results from these studies will provide a foundation for identifying virulence factors and markers, also at the molecular level.