Distribution and Genetic Characterization of Border Disease Virus Circulating in Sardinian Ovine Flocks

Border Disease (BD) is a worldwide distributed pathology accountable for significant losses
in the sheep and goat farming industry. The etiological agent is a Pestivirus within the family Flaviviridae
called border disease virus (BDV). Despite the Sardinian ovine population being by far larger than any
other Italian region, the prevalence and distribution of BD on the island are unknown. Here, we aim
to determine the distribution of BDV in sheep flocks and to genetically characterize the circulating
strains in Sardinia. The geographical distribution, antibody positivity, and viral genome presence
have been analysed for 1286 sheep flocks distributed all over the island from bulk tank milk sampled
between May 2014 and 2015. Of the flocks tested, 11.28% (95% CI 9.66–13.12) resulted positive for
the presence of anti-pestivirus antibodies with an uneven distribution between Sardinian provinces.
In addition, using RT-PCR, nine BDV genomes were amplified from milk pellets of the seropositive
samples. Phylogenetic analysis revealed that all the viruses amplified clustered in the same group
classified as BDV-7. This represents the first study on the distribution of pestivirus infection and genetic
characterization of BDV strains circulating in the Sardinian sheep population. Future studies are needed
to clarify the origin, the evolution, and the epidemiology of BDV-7 in Sardinia.