Publication - Factsheet

Diseases of wild and farmed Finfish

Published: 17 Dec 2019

Some fish and shellfish diseases of particular significance in Scotland.

Diseases of wild and farmed Finfish
Salmonid alphavirus (SAV)

Salmonid alphavirus (SAV)

Salmonid alphaviruses are serious pathogens of farmed Atlantic salmon and rainbow trout in Europe. SAVs are single stranded RNA viruses which are divided into 6 genetic subtypes and belong to the genus Alphavirus in the family Togaviridae. SAV3 is found in Norway. SAV 1, 4, 5 and 6 are found in salmon in the UK with SAV 1 being the biggest problem and SAV 2 is associated with rainbow trout sleeping disease throughout Europe including the UK. The clinical signs of the disease can include lethargy, loss of appetite, abnormal swimming and high mortality.

The diagnostic methods include:

  • Histopathology
  • Immunofluorescence antibody test (IFAT)
  • Real-Time PCR and Sequencing
  • Virus isolation