Phylogenetic analysis of NS5B gene of classical swine fever virus isolates indicates plausible Chinese origin of Indian subgroup 2.2 viruses

Twenty-three CSFV isolates recovered from field outbreaks in various parts of India during 2006-2009 were used for genetic analysis in the NS5B region (409 nts). Seventeen of these were studied earlier [16] in the 5'UTR region. Phylogenetic analysis indicated the continued dominance of subgroup 1.1 strains in the country. Detailed analysis of a subgroup 2.2 virus indicated the plausible Chinese origin of this subgroup in India and provided indirect evidence of routes of CSFV movement within South East Asia region.