Systematic Veterinary Virology

REPLICATION

• Replication occurs in the cytoplasm and is rapid. The glycoprotein spikes over the envelope of the virus are responsible for binding of the virus to cellular receptors.
• Upon entry into the cell the virus gets uncoated and (+) sense genomic RNA acts as mRNA and is partially translated (5' end) to produce NS proteins. These NS proteins are responsible for replication, forming a complementary (-) strand (replicative intermediate), which acts as the template for further (+)strand synthesis.
• Two species of (+) RNA are synthesized, full length genomic RNA and sub-genomic mRNAs. Translation of the newly synthesized sub-genomic RNA results in production of structural proteins. Assembly occurs at the cell surface, and the envelope is acquired as the virus buds from the cell.