 Pestiviruses are small, spherical, single-stranded, enveloped RNA viruses of 40 to 60 nm in diameter.The genome consists of a single, linear, positive-sense, single-stranded RNA molecule of approximately 12.3 kb.Two BVDV genotypes are recognised, based on the nucleotide sequence of the 5’untranslated (UTR) region; BVDV-1 and BVDV-2.