Rovac is the possible ancestor of the Russian lapinized vaccines LK-VNIVViM and CS strains but not the Chinese strain (C-strain) vaccine against classical swine fever.

Classical swine fever (CSF), or hog cholera, is a highly contagious disease that emerged in the first half of the nineteenth century. To fight against the disease and protect pigs, different vaccines were developed, including early generation of lapinized Rovac strain and the later development of the “Chinese” strain (C-strain). However, details of the development of these vaccines are lost in history. In order to investigate the phylogenetic relationship between the Rovac and other lapinized vaccines, this study determined the genome sequence of the Rovac, which comprised 12,304 nucleotides, notably with the 3′untranslated region (3′UTR) containing a 13-nucleotide insertion. The near-complete genome of Russian vaccine strain LK-VNIVViM was determined by next-generation sequencing on Illumina MiSeq platform. Whole genome phylogenetic analysis revealed a closer relationship of the Rovac strain with the Russian LK-VNIVViM, CS strain and its derivative RUCSFPLUM (genotype 1.2), rather than with the C-strain (genotype 1.1). In addition, it demonstrated an ancestry role of the LK-VNIVViM in relation to the CS strain and RUCSFPLUM. The study suggested that the Rovac vaccine is the possible ancestor of the Russian vaccine strains but not the C-strain vaccine.