First isolation of border disease virus in Japan is from a pig farm with no ruminants

The first isolation of border disease virus (BDV) in Japan was from a pig farm of the farrow-to-finishing type that kept no small ruminants or cattle. The infection was detected in the course of sero-surveillance for classical swine fever virus (CSFV) in Japan. The infected pigs had no clinical symptoms of CSFV or other disease; nevertheless, a high sero-positive rate of 58.5% was identified. A persistently infected pig with the BDV was found and suspected to be the cause of sero-prevalence in the farm. The isolated BDV was genetically close to BDV strains from New Zealand, but there was no epidemiological evidence concerning the route(s) of the invasion into the farm.