Prevalence surveys performed in Europe since the late 1970s up to the present show that BVDV has been endemic in all countries where no systematic control has been initiated. Under such conditions, approximately 50% of all herds have PI animals, and 90% of all cattle become exposed during their lifetime. Countries where systematic BVDV control schemes have been implemented, such as Norway, Sweden, Finland and Denmark, are now almost free of BVDV.