Virological screening of wild and farmed fish species: Application of innovative Taqman multiplex real-time PCR protocols

Global demand for seafood is growing and fish stock maintenance becomes a pressing issue, making aquaculture production of capital importance in terms of fish resources sustainability. Therefore, fish disease outbreaks are a significant constraint to fisheries trade and aquaculture production, affecting economic development worldwide. In this study, a virological screening in wild and farmed fish populations was performed by two TaqMan multiplex real-time PCR assays developed to identify/quantify, in a single run, four viruses responsible for major economic losses in fisheries, namely: infectious pancreatic necrosis virus (IPNV), infectious hematopoietic necrosis virus (IHNV), viral haemorrhagic septicaemia virus (VHSV) and viral nervous necrosis virus (VNNV). A total of 323 fish were assessed, being the majority from four species from the Atlantic coast: gilthead seabream and seabass, two extensively farmed species in aquaculture and captured in the wild, and sardine and Atlantic horse mackerel, two of the most consumed fish species in Portugal. The genomes of IPNV (genogroup II) and VHSV (genogroup Ie) were detected in one pool of gilthead seabream and one pool of Atlantic horse mackerel, confirming the importance of molecular tools for viral screening, especially in asymptomatic hosts, since viral infections may impart major economic losses to the fish industry.