Schematic representation of a generic bunyavirus virus particle (A) and SBV antigenomes (B). (A) The bunyavirus virion has a diameter of 80 to 120 nm. The three RNA segments (S, M and L) associate with the L polymerase and the N nucleoprotein to form RNP. (B) The three antigenomic RNA encode for several predicated ORF as indicated by double-sided arrows. The number of nucleotides (nt) of the different ORF and the corresponding number of amino acids (aa) are shown . Putative co-translational cleavage sites of the polyprotein encoded by segment M are indicated by scissors but are not yet characterised.