Genetic diversity of international bovine viral diarrhoea virus (BVDV) isolates: identification of a new BVDV-1 genetic group Stefan Vilcek, Branislav Durkovic, Mariana Kolesárová, Irene Greiser-Wilke and David Paton Vet. Res., 35 5 (2004) 609-615 DOI: 10.1051/vetres:2004036