Comparative genetic characterization of Porcine Circovirus type 2 samples from German wild boar populations

PCV-2 is involved in "postweaning multisystemic wasting syndrome" (PMWS), "porcine dermatitis and nephropathy syndrome" (PDNS), respiratory and reproductive disorders, and thereby plays a crucial role in today's swine production world-wide. The virus is apparently ubiquitous in domestic pigs and has also been demonstrated in wild pigs. Up to now, a characterization of PCV-2 samples from wild pigs, which might help to estimate the possible role of wild pigs as sources of domestic pig infection, has not been carried out. Spleen samples from 16 PCV-2-positive wild pigs from hunting grounds of four regions in Germany were used for the analysis of the viral genome. In one sample, the complete sequence of the genome was determined. In the other, a 742 nucleotide fragment from the highly variable capsid sequence of the ORF2 was sequenced. Analysis of the sequences led to the identification of three PCV-2 strains. One strain, representing 14 of the 16 samples, was closely related with Chinese, but not with German strains. The genome of this strain was shortened by one nucleotide by a deletion close to the end of ORF2. The deletion led to a shift of the stop-codon and to the insertion of a further codon. Two further strains differed in up to 4.7% of nucleotides and up to 10.5% of amino acids (aa). These strains were aligned with clusters of PCV-2 samples from mainly French and German domestic origin.