J Fish Dis 2014 Apr 12;37(4):371-83. Epub 2013 May 12.
Fish Virology Department, Istituto Zooprofilattico Sperimentale delle Venezie, viale dell'Università, Legnaro, Padova, Italy; EURL for Fish Diseases, DTU VET, Frederiksberg C, Copenhagen, Denmark.
Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a severe pathological condition caused by RNA viruses belonging to the Nodaviridae family, genus Betanodavirus. The disease, described in more than 50 fish species worldwide, is considered as the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of the aquaculture industry. To date, four different genotypes have been identified, namely red-spotted grouper nervous necrosis virus (RGNNV), striped jack nervous necrosis virus (SJNNV), tiger puffer nervous necrosis virus and barfin flounder nervous necrosis virus, with the RGNNV genotype appearing as the most widespread in the Mediterranean region, although SJNNV-type strains and reassortant viruses have also been reported. Read More