Francisella philomiragia subsp. noatunensis infection in farmed cod (Gadus morhua): Diagnosis, characterisation, and environmental studies

Farming of marine fish species in Norway is currently going through what may be described as a boom period. A combination of technological innovation in the field of larval production, combined with regulated wild-fisheries and concurrent favourable marke t prices, have made farming of marine species, in particular cod (Gadus morhua), increasingly commercially attractive. Subsequently, production of farmed cod is currently increasing dramatically and is expected to increase significantly within the next fe w years. As expected, the introduction and increased production of a new species to culture has not been without development of novel diseases. In common with the early days of salmon farming, the primary diseases are found to be bacterial in nature. A ne w systemic infection caused by F. philomiragia subsp. noatunesis has recently emerged and has rapidly developed into a major threat to the industry. The focus of the proposed project is, therefore, further characterisation of Francisella spp. isolated fro m fish, in particular that from cod, and precise taxonomic placement of relevant species. A proposed draft genome sequence of F. philomiragia subsp. noatunensis will, through comparative studies of the several available Francisella genomes available to us through our cooperation with the Swedish Defence Agency, will make identification of virulence related traits e.g. pathogenicity islands, type IV secretion systems and possible vaccine candidates etc. possible. The diversity of Francisella spp. in aquati c and terrestrial environments will be studied such that the general level of knowledge relating to the Francisella population and ecology will be increased. The risks of transmission between different fish types and types of organism will be investigated .