Border Disease Virus

Abstract

Border disease virus (BDV) is a pestivirus (genus Pestivirus) within the family Flaviviridae and is closely related to Hog cholera virus (Classical swine fever virus) and Bovine viral diarrhea viruses (BVDV). Nearly all isolates of BDV are noncytopathic in cell culture. The virus causes Border disease (BD), a congenital disease of sheep and goats, first reported from the border region of England and Wales but since then, recorded worldwide. BD in sheep is characterized by barren ewes, abortion, stillbirths, and the birth of small, weak lambs, some of which have tremor, abnormal body conformation, and hairy fleece (‘hairy-shaker’ or ‘fuzzy’ lambs). The disease in goats is rare, with abortion predominating. BDV infections are most commonly associated with sheep, but all domesticated and wild cloven-hoofed artiodactyls are likely to be susceptible. As well as sheep and goats, pigs, cattle, reindeer, European bison, and chamois have yielded BD viruses. Vertical transmission is important in the epidemiology of BD. The infection of fetuses in early gestation can result in the birth of persistently infected (PI) lambs. These PI lambs are viremic, they have no antibody to BDV, and they constantly excrete virus. These PI animals are a potent source of infection and ensure the spread of virus within susceptible populations.