Enveloped. Usually rounded but can be filamentous. The virions are 90-130 nm in diameter.


segmented ssRNA(-) linear genome, encapsidated by nucleoprotein (NP) Contains 8 segments coding for at least 8 proteins. Segments size range from 0.8 to 2.2 kb. Genome total size is about 13.5 Kb.


Viral RNA polymerase (PB1, PB2 and PA) transcribes one mRNA from each genome segment. Transcription is primed by cap snatching. mRNA are polyadenylated by the viral polymerase stuttering on a poly U track. Segment 7 mRNA can be alternatively spliced, giving rise to mRNA coding for P6 and P7 proteins.



  1. Virus attaches to sialic acid receptor though HA protein and is endocytosed by clathrins in the host cell.
  2. endosome acidification induces fusion of virus membrane with the vesicle membrane; encapsidated RNA segments migrate to the nucleus.
  3. Transcription of genomic segments by the viral polymerase produces mRNAs that are capped and polyadenylated by the viral polymerase.
  4. Replication of genomic segments.
  5. High level of M1 protein induces genomes segments export from nucleus by NEP protein.
  6. Virus assembly and budding occurs at the plasma membrane.

Matching UniProtKB/Swiss-Prot entries

10 entries grouped by strain (browse by keywords)

10 entries

Infectious salmon anemia virus (isolate Atlantic salmon/Norway/810/9/99) (ISAV) reference strain

RDRP_ISAV8 RNA-directed RNA polymerase catalytic subunit (EC (Polymerase basic protein 1) (PB1) ...
PA_ISAV8 Polymerase acidic protein (RNA-directed RNA polymerase subunit P2)
P6_ISAV8 Protein P6
P4_ISAV8 Protein P4
P5_ISAV8 Protein P5
P7_ISAV8 Protein P7
PB2_ISAV8 Polymerase basic protein 2 (RNA-directed RNA polymerase subunit P3)
NCAP_ISAV8 Nucleoprotein (Nucleocapsid protein) (Protein N)
FUS_ISAV8 Fusion glycoprotein F0 [Cleaved into: Fusion glycoprotein F1; Fusion glycoprotein F2]
HEMA_ISAV8 Hemagglutinin-esterase (HE protein) (EC