Ovidae and Capridae

Border disease (BD) is a viral disease of sheep and goats first reported in sheep in 1959 from the border region of England and Wales, and since recorded world-wide. Distribution of the virus is world-wide. Prevalence rates vary in sheep from 5% to 50% between countries and from region to region within countries. Clinical signs include barren ewes, abortions, stillbirths and the birth of small weak lambs. Affected lambs can show tremor, abnormal body conformation and hairy fleeces (so-called ‘hairy-shaker’ or ‘fuzzy’ lambs) and the disease has been referred to as ‘hairy shaker disease’. Vertical transmission plays an important role in the epidemiology of the disease. Infection of fetuses can result in the birth of persistently infected (PI) lambs. These PI lambs are viraemic, antibody negative and constantly excrete virus. The virus spreads from sheep to sheep, with PI animals being the most potent source of infection. Infection in goats is less common with abortion being the main presenting sign. In many regions the commonest cause of BD is the pestivirus border disease virus (BDV), but in some parts of the world, bovine viral diarrhoea virus (BVDV) may be a more common cause of BD. The source of BVDV for sheep often is close contact with cattle.