Seroprevalence of antibodies to Pestivirus infections in South Australian sheep flocks

OBJECTIVE: Bovine viral diarrhoea virus (BVDV) and border disease virus (BDV) are of the genus Pestivirus. They are known to cause significant reproductive and production losses, with BVDV acknowledged as a major source of economic loss to the Australian cattle industry. Very little is currently known about the prevalence and effect of pestiviruses in the Australian sheep industry. The present study aimed to examine the seroprevalence and effect of both BVDV and BDV in South Australian sheep flocks. METHODS: In total, 875 breeding ewes on 29 properties were serologically tested by ELISA, AGID and VNT assays for the presence of Pestivirus-specific antibodies. RESULTS: Three (0.34%) individual animals returned serological results suggestive of previous BDV infection. All three positive animals were collected from one property, giving a property level seroprevalence of 3.45% and a within-flock seroprevalence of 10%. CONCLUSION: The results suggested that BDV infection is present, albeit at a very low incidence, in the South Australian sheep flock and BVDV infection appears to be absent. Consequently, pestiviruses are unlikely to impair production in South Australian sheep populations.