A notifiable fish disease has hit a farm in Yorkshire in the second outbreak of the virus in UK history.
According to reports from the Centre for Environment Fisheries and Aquaculture Science (Cefas), scientists are investigating the source of an outbreak of Viral Haemorrhagic Septicaemia (VHS) at a trout farm in Yorkshire.
The virus, which has only been seen once before in the UK in farmed Turbot, is considered a very serious threat to trout stocks and fish farms have a legal responsibility to notify the authorities if they suspect an infection.
The virus is most commonly seen in Rainbow trout and can rapidly kill up to 80% of the fish. Other trout in the UK are naiive - previously unexposed and have not been previously infected or built up immunity - so the disease has the potential to cause widespread damage to native fish stocks if it manages to get into the wild.
As a preventative measure up to 50,000 trout at the infected farm have been culled.
Cefas has placed movement restriction orders on fish farms along the entire length of the River Ouse in Yorkshire in an attempt to contain the disease.
Cefas says that other fish farms in the area which may have had contact with the infected farm have been inspected but they have not yet found any clinical evidence of the disease at other locations:
"Results of tests from samples are expected soon (tests can take up to two weeks) and inspections of other sites in the Ouse catchment area are due to be completed later this week.
"The affected farm has now been cleared of all fish and plans are in place to disinfect the site.
"There is no treatment for VHS. As a List II notifiable disease there is a legal obligation to report any suspected outbreaks of VHS to the Fish Health Inspectorate."
VHS is a species of Novirhabdovirus and occurs in both marine and freshwater, where it primarily infects salmonid fishes. However, the disease can also kill Pike, Cod, Whiting a range of popular food fish species.