In order to evaluate the genetic variability of Porcine parvovirus (PPV), the complete capsid protein sequences (VP1/VP2) from seven recent field isolates from Germany, one isolate from the UK and one German vaccine strain were sequenced and analysed, along with two American (NADL-2 and Kresse), three Asian and 22 Brazilian partial PPV sequences retrieved from GenBank. The analysis revealed a high degree of diversity: 1?2-2?6 % at the nucleotide level and 1?2-6?8 % at the amino acid level. Phylogenetic analysis defined two German clusters: one formed by four German isolates and the English, Asian and American sequences; and the second, distinct cluster formed by the other three of the seven German isolates examined. The latter cluster was still observed when the 22 partial sequences (853 nt of the 39 terminus of the VP2 gene) from the Brazilian isolates were included in the analyses, indicating that the VP2 sequence determines the phylogeny.Porcine parvovirus (PPV) is an important cause of reproductive failure in swine, characterized by fetal death, mummification, stillbirths and delayed return to oestrus (Mengeling, 1999). It is classified in the genus Parvovirus, the subfamily Parvovirinae and the family Parvoviridae, and contains a single-stranded (minus-strand) DNA genome of about 5 kb. The large ORF1 and the small ORF3, in the left half of the genome, code for the non-structural proteins NS1, NS2 and NS3. ORF2, in the right half of the genome, encodes the structural proteins VP1, VP2 and VP3. VP1 and VP2 are a result of alternative spliced RNAs giving VP1 a specific N terminus of 150 aa. VP3 is generated by proteolytic cleavage of VP2 (Ranz et al., 1989;Bergeron et al., 1993).Although the three structural proteins form the icosahedral non-enveloped capsid, VP2 can assemble into virus-like particles (VLPs) by itself and the immunogenic activity of the VLPs is indistinguishable from that of inactivated whole-virus vaccines (Martinez et al., 1992). Nine linear Bcell epitopes have been defined within the major capsid protein VP2, but so far only peptides from the N terminus of VP2 are known to induce virus-neutralizing antibodies (Kamstrup et al., 1998).The capsid proteins VP1/VP2 of the carnivore parvoviruses canine parvovirus (CPV) and Feline panleukopenia virus (FPV) determine the host range (Chang et al., 1992;Truyen et al., 1995;Shackelton et al., 2005). For PPV, however, not much is known about host-range determinants. Two amino acid differences (one in VP1/VP2 and one in NS1) extend the host range for PPV in cell culture from porcine to porcine and canine cells (Vasudevacharya et al., 1992). The pathogenicity of the highly virulent PPV Kresse isolate appears to be determined by only three substitutions in the VP1/VP2 protein (Bergeron et al., 1996). The threedimensional structure of empty PPV capsids was determined by X-ray crystallography and was found to be similar to that of the related parvoviruses CPV and FPV. The three differences in amino acid sequence associated with the pathogenic phenotype of K...
