Genetic characterization of border disease virus (BDV) isolates from small ruminants in Italy

Border disease virus (BDV) belongs to the Pestivirus genus in the family Flaviviridae. Genetic analyses of pestiviruses that have been isolated from sheep and goat have led to the proposal that BDV isolates can be phylogenetically segregated into at least seven clusters, subtypes BDV-1 to BDV-7. In order to investigate the genetic heterogeneity of small ruminant pestivirus isolates in Italy, a selection of 5′-UTR sequences from isolates that were collected from clinical specimens between 2002 and 2014 was analysed. Phylogenetic reconstructions indicated that the BDV-positive samples clustered within the BDV-1, BDV-3, BDV-5, and BDV-7 groups. These results suggested high genetic diversity within the Italian BDV field isolates. The phylogenetic analysis indicated the first evidence of BDV-1 and BDV-5 circulation in Italy. The marked diversity of the pestivirus isolates might reflect the sheep trade with foreign countries.