Detection of infectious pancreatic necrosis virus (IPNV) from the environment in the vicinity of IPNV‐infected Atlantic salmon farms in Scotland

Abstract

Infectious pancreatic necrosis virus (IPNV) has been isolated from mussels, sediment and surface water in the vicinity of clinically infected salmon farms, at shore bases supplying the farms and for several hundred metres distance from farms in the direction of current flow. There was evidence of decreasing prevalence of IPNV in mussels from Shetland once IPN outbreaks subsided, indicating they are an unlikely source of re-infection on farms. There was little evidence of persistence in the environment, although conclusions were complicated by the presence of IPNV on neighbouring farms 1 year after the outbreak.

Infectious Pancreatic Necrosis Virus Causing Clinical and Subclinical Infections in Atlantic Salmon Have Different Genetic Fingerprints

“…Survivors of IPNV infection become persistently infected and are sources of infection to naïve fish (Roberts and Pearson, 2005). The ability of the virus to survive in the environment and in alternative hosts (Mulcahy and Pascho, 1984; Rimstad, 2003; Gregory et al, 2007) ensures that the infection is perpetuated through subsequent stocks of fish at particular sites.…”

Isolation of a novel aquatic birnavirus from rainbow trout Oncorhynchus mykiss in Australia

“…IPNV has also been isolated from mussels, sediment and sea water during outbreaks of IPN in sea farms (Gregory et al 2007). Persistence in the marine environment is shortlived -the concentration of virus peaking around a month after a disease event and de clining over the following 6 to 8 mo (Gregory et al 2007). In the freshwater environment the prevalence in free-ranging fish was reported to be low, and titres in water are approximately 107-fold lower than those used for the experimental challenge.…”

Experimental Transmission of Infectious Pancreatic Necrosis Virus from the Blue Mussel, Mytilus edulis, to Cohabitating Atlantic Salmon (Salmo salar) Smolts

“…Although IPN outbreaks in Atlantic salmon have not been a recent problem in North America, there are endemic strains of IPNV in the region (32,33). Further, IPNV can persist in seawater and sediments and has been detected in many bivalve species (23,34,35). Therefore, Atlantic salmon may be at risk for becoming infected with IPNV during the stress of saltwater acclimation.…”

“…Mussels may increase both the risk of infection with IPNV in the post-smolts in addition to increase the risk of IPN disease outbreak. The prevalence of IPNV in Atlantic salmon is increasing in countries with intensive Atlantic salmon farming such as Scotland and Norway (22,23). Although IPN outbreaks in Atlantic salmon have not been a recent problem in North America, there are endemic strains of IPNV in the region (32,33).…”

“…In addition to asymptomatic farmed fish, infectious IPNV has been isolated from cohabitating farmed and wild fish, shellfish, sediments below the net pens, and birds (7,23,24). IPNV has been isolated from wild marine fish (including but not limited to saithe, Atlantic cod, pollock, and hake) species in the vicinity of marine salmon farms but has also been detected in wild salmonid fish that have had no contact with hatchery-reared fish (25).…”