Border disease (BD) virus belongs to the genus Pestivirus together with bovine viral diarrhoea virus (BVDV) genotypes 1 and 2 and classical swine fever virus (Pletnev and others 2011). The pathogenicity of BD virus for bovine fetuses has been recognised early (Gibbons and others 1974), but only since 1994 has renewed attention been drawn to the mutual transmission between species (Carlsson and Belak 1994). Transmission of BD virus from persistently infected sheep to cattle was demonstrated (Krametter-Frotscher and others 2008, 2009, Reichle 2009, Braun and others 2013, 2014). Nevertheless, reports on clinical disease in cattle caused by BD virus are rare (Cranwell and others 2007, Krametter-Frotscher and others 2010, McFadden and others 2012). The present report describes the radiological and pathological findings in three calves (Table 1) persistently infected with BD virus. Persistent infection with pestivirus was suspected based on an initial positive ear notch sample taken within 1 week after birth on the three different farms of origin and tested in private laboratories by ELISA or RT-PCR. This was later confirmed in our lab using real-time RT-PCR and serology on blood samples collected independently on at least two occasions, a minimum of 17 days apart. Thus, all calves were strongly positive for viral RNA and negative for serum antibodies against pestiviruses at the latest time point analysed, that is, at the age of 2, 8 and 15 months after birth for animals 1, 2 and 3, respectively. This identifies all three calves as persistently infected with a pestivirus. Genotyping based on the sequence within the 5′ untranslated region of the pestiviral genome (Bachofen and others 2008) revealed that calves were persistently infected with BD virus ‘Switzerland’ (Peterhans and others 2010). This was corroborated by the fact that (i) the mother animals of all three calves possessed …
