Enveloped, spherical, about 45-60 nm in diameter. The virion is comprised of an isometric core of 20-30 nm surrounded by a lipid-containing envelope. The RNA genome associates with the N protein to form the nucleocapsid.


Monopartite, linear, ssRNA(+) genome of 12-16kb in size, capped, and polyadenylated. The leader RNA (65-89 bp) at the 5’ end of the genome is also present at the end of each subgenomic RNAs.


The virion RNA is infectious and serves as both genome and viral messenger RNA. ORF1b is translated by a ribosomal frameshifting. Polyproteins pp1a and pp1ab are processed into the viral polymerase (RdRp) and other non-structural proteins involved in RNA synthesis. Structural proteins are expressed as subgenomic RNAs. The mRNA2 is bicistronic. PRRSV, LDV and SHFV also express a truncated polyprotein 1aTF due to a ribosomal frameshifting in the nsp2 gene.
The 3’ proximal region of SHFV contains in addition a large insertion that may encode three additional glycoproteins. Protein GP2 and 5a are produced by leaky scanning from the E and gp5 subgenomic mRNA respectively.



  1. Attachement to host receptors mediates clathrin-mediated endocytosis of the virus into the host cell.
  2. Fusion of virus membrane with the endosomal membrane. ssRNA(+) genome is released into the cytoplasm.
  3. Synthesis and proteolysis of replicase polyproteins.
  4. Replication occurs in viral factories. A dsRNA genome is synthesized from the genomic ssRNA(+).
  5. The dsRNA genome is transcribed/replicated thereby providing viral mRNAs/new ssRNA(+) genomes.
  6. Synthesis of structural proteins encoded by subgenomic mRNAs.
  7. assembly and ESCRT-independent budding at the membranes of endoplasmic reticulum (ER), intermediate compartments, and/or Golgi complex.
  8. Release of new virions by exocytosis.

Host-virus interaction

Apoptosis modulation

The equine arteritis virus and PRRSV induce apoptosis via host caspases activation (caspase-8 and mitochondria-dependent caspase-9)

Autophagy modulation

PRRSV induces autophagy to promote virus replication .

Innate immune response inhibition

PRRSV clearly inhibits the type-I IFN response and down-regulates TLR3, TLR7, and TLR8 expression.
At least three non-structural proteins (Nsp1, Nsp2, and Nsp11) play roles in the IFN suppression and NF-κB pathways :

Nsp1α subunit inhibits the IκB phosphorylation in the cytoplasm and therefore the activation of NF-κB.

Nsp1β inhibits phosphorylation of STAT1 and nuclear translocation of ISGF3 complex (composed of STAT1, STAT2 and IRF9). Nsp1β prevents IRF3 activation, thereby interfering with the RIG-I signaling pathway .

Nsp2 inhibits IFN production by blocking the ubiquitinylation of phosphorylated IκB and phosphorylation of IRF3 through the OTU domain. Nsp2 has the potential to deconjugate ISGylation.

Nsp11 suppresses IFN-β production through degradation of IPS-1 mRNA. For the second wave of IFN signaling, PRRSV Nsp1β blocks the phosphorylation of STATs and inhibits the nuclear translocation of ISGF3 complex (composed of STAT1, STAT2 and IRF9).

Matching UniProtKB/Swiss-Prot entries

39 entries grouped by strain (browse by keywords)

All proteins are shown (view only 30 complete proteome entries)

10 entries

Porcine reproductive and respiratory syndrome virus (strain Lelystad) (PRRSV) reference strain

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E_PRRSLEnvelope small membrane protein (Protein E) (Glycoprotein 2b) (Protein GP2b) ...
GP2A_PRRSLGlycoprotein 2a (Protein GP2a) (GP2)
GP3_PRRSLGlycoprotein 3 (Protein GP3)
GP4_PRRSLGlycoprotein 4 (Protein GP4)
GP5_PRRSLGlycoprotein 5 (Protein GP5) (G(L))
M_PRRSLMembrane protein (Protein M)
NCAP_PRRSLNucleoprotein (Nucleocapsid protein) (Protein N)
ORF5A_PRRSLStructural protein ORF5a
RPOA_PRRSLReplicase polyprotein 1ab (ORF1ab polyprotein)
RPOTF_PRRSLReplicase polyprotein 1TF (ORF1ab polyprotein)

9 entries

Equine arteritis virus (strain Bucyrus) (EAV) reference strain

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E_EAVBUEnvelope small membrane protein (Protein E) (Glycoprotein 2a) (Protein GP2a)
GP2B_EAVBUGlycoprotein 2b (Protein GP2b) (GP(S))
GP3_EAVBUGlycoprotein 3 (Protein GP3)
GP4_EAVBUGlycoprotein 4 (Protein GP4)
GP5_EAVBUGlycoprotein 5 (Protein GP5) (G(L))
M_EAVBUMembrane protein (Protein M)
NCAP_EAVBUNucleoprotein (Nucleocapsid protein) (Protein N)
RPOA_EAVBUReplicase polyprotein 1ab (ORF1ab polyprotein)

9 entries

Porcine reproductive and respiratory syndrome virus (isolate Pig/United States/SD 01-08/2001) (PRRSV)

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1ATF_PRRSSTruncated polyprotein 1aTF
E_PRRSSEnvelope small membrane protein (Protein E) (Glycoprotein 2b) (Protein GP2b) ...
GP2A_PRRSSGlycoprotein 2a (Protein GP2a) (GP2)
GP3_PRRSSGlycoprotein 3 (Protein GP3)
GP4_PRRSSGlycoprotein 4 (Protein GP4)
GP5_PRRSSGlycoprotein 5 (Protein GP5) (G(L))
M_PRRSSMembrane protein (Protein M)
NCAP_PRRSSNucleoprotein (Nucleocapsid protein) (Protein N)
RPOA_PRRSSReplicase polyprotein 1ab (ORF1ab polyprotein)

3 entries

Lactate dehydrogenase elevating virus (strain C) (LDV)

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NCAP_LDVCNucleoprotein (Nucleocapsid protein) (Protein N)
RPOA_LDVCReplicase polyprotein 1ab (ORF1ab polyprotein)
VPX_LDVCProtein X (Envelope protein) (VpX)

2 entries

Lactate dehydrogenase-elevating virus (LDV)

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NCAP_LDVNucleoprotein (Nucleocapsid protein) (Protein N)
VPX_LDVProtein X (Envelope protein) (VpX)

2 entries

Porcine reproductive and respiratory syndrome virus (strain VR-2332) (PRRSV)

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ORF5A_PRRSRStructural protein ORF5a
RPOA_PRRSRReplicase polyprotein 1ab (ORF1ab polyprotein)

1 entry

Lactate dehydrogenase elevating virus (strain Plagemann) (LDV)

RPOA_LDVPReplicase polyprotein 1ab (ORF1ab polyprotein)

1 entry

Porcine reproductive and respiratory syndrome virus (strain 16244B) (PRRSV)

RPOA_PRRS1Replicase polyprotein 1ab (ORF1ab polyprotein)

1 entry

Porcine reproductive and respiratory syndrome virus (strain HB-1) (PRRSV)

RPOA_PRRSBReplicase polyprotein 1ab (ORF1ab polyprotein)

1 entry

Simian hemorrhagic fever virus (SHFV)

RPOA_SHFVReplicase polyprotein 1ab (ORF1ab polyprotein)