Pseudorabies virus in European wild boar from central Italy.

Tissue and blood samples were collected from 152 wild boars (Sus scrofa) from the Maremma area (Grosseto district, Central Italy) between November 2002 and January 2003. The presence of pseudorabies virus (PRV) antibodies, antigen, and DNA were confirmed by an enzyme-linked immunosorbent assay (ELISA), immunohistochemistry, and polymerase chain reaction (PCR), respectively. Of 152 animals, 62 (41%) were positive for viral antigen in tonsillar tissue. Of the 80 serum samples that were suitable for testing, 41 (51%) were positive for PRV antibodies. Positive immunohistochemistry results were confirmed by PCR. A significantly higher prevalence of PRV antigen and seroprevalence was detected in older animals. No differences were detected between males and females or for animals coming from different areas sampled. Results confirm that PRV is endemic in this wild boar population with a high prevalence of infection. The results of immunohistochemistry investigations demonstrated that a large number of wild boars harbor PRV in tonsillar tissues and should be considered as an important reservoir of PRV.