[Clinical aspects and diagnosis of border disease]

The term Border disease (BD) refers to a clinical condition of newborn lambs that results from congenital infection by a pestivirus (family: flaviviridae), occurring during the first one-half of gestation. The most prominent clinical features are tonic-clonic tremors and hairy fleece ("hairy shaker" symptomatology). Moreover early transplacental infection often causes fetal death, abortion or stillbirth and teratogenic disorders. In Germany there are only few reports on clinical cases of BD, however in sheep antibodies have been found frequently in different regions of the country. Similar to the situation with bovine viral diarrhea/mucosal disease (BVD/MD) the existence of persistently infected sheep is proven. As permanent carriers and initiators of clinically apparent as well as more commonly clinically inapparent infections persistently infected animals are of great epidemiological importance. As a new method for the diagnosis of persistently Border disease Virus (BDV) infected sheep flow cytometry is presented. This special procedure of immunofluorescence has the overall advantage of rapid and reliable detection of pestivirus-infected cells by a highly conserved viral epitope (p 80/125). All biotypes of pestiviruses (non cytopathic = ncp and cytopathic = cp isolates) are recognized equally well by monoclonal antibodies (mAb) which provides some advantage compared to conventional techniques because most virus isolates from sheep belong to the ncp biotype.