Experimental susceptibility of turbot Scophthalmus maximus to viral haemorrhagic septicaemia virus isolated from cultivated turbot

Juvenile pathogen-free turbot were infected with a viral haemorrhagic septi caemia virus (VHSV) isolate recovered from turbot cultivated on the island of Gigha, West Scotland. Mortality of 100% was recorded in fish infected vi a the intra-peritoneal (i.p.) route. Horizontal transmission of VHSV in sea water was demonstrated by cohabitation of naive fish with i.p. infected fi sh at a ratio of 1:1. The total cumulative average mortality in cohabiting fish was 60% by 60 d post-infection. Turbot infected via an immersion route exhibited a cumulative average mortality of 71% by the end of the experime nt. VHSV identified by enzyme-linked immunosorbent assay (ELISA) was recove red from both organ (kidney and spleen) and brain samples of individual fis h that died following infection by all experimental routes. These findings pose significant implications regarding the persistence of VHSV and its rol e in limiting natural populations of marine fish species. In addition, the establishment of infection models for the transmission of VHSV in sea water is of fundamental importance to the development of anti-VHSV vaccines in i mportant commercial species such as turbot.