The 5'-untranslated genomic region of the pestivirus strain Europa, originated in human leucocytes and previously identified as bovine diarrhea virus (BVDV), was amplified by reverse transcription-PCR and sequenced. Analyses based on primary nucleotide sequence homology and on secondary palindromic sequence structures characteristic to genotypes revealed that this human isolate should be assigned to a novel genotype of pestivirus, type Ic. This newly emerged genotype was related to, but distinguishable from the three known BVDV genotypes, Ia, Ib and II. Three other bovine field isolates of BVDV originated from Germany were also found to belong to this new genotype Ic. Within pestivirus genotype Ic strains, the overall nucleotide sequence homology was 95-96%, and 88-92%, 88-90% and 77-79% with the other BVDV genotypes Ia, Ib and II, respectively. With the strains from border disease virus (genotype III) and hog cholera virus (genotype IV), homologies were less than 75%.