Porcine circovirus type 2 (PCV2) antigen localisation and post-weaning multisystemic wasting syndrome (PMWS) in free-ranging wild boar (Sus scrofa ssp scrofa) in Italy

Wild boar (Sus scrofa ssp scrofa) is a host of porcine circovirus 2 (PCV-2), and infection in this species has been reported in many countries. This study sampled tissues from 348 wild boars in Italy in the provinces of Bologna, Padua and Pisa. No clinical signs or macroscopic lesions were recorded in the sampled animals. Immunolocalisation for PCV-2 was performed on tissues, and viral antigen was disclosed in 38 animals, 11 immunohistochemistry (IHC) positive out of 148 (7.43%) sampled in northern Italy and 27 immunofluorescence (IF) positive out of 200 (13.5%) sampled in central Italy, respectively. Histologically, 19 cases displayed post-weaning multisystemic wasting syndrome (PMWS) histological lesions, but PCV2 was only proved in nine of them (three from Bologna and Padua by IHC and six from Pisa by IF). Animals aged 7 to 8 months were the most affected by PCV2 infection, suggesting an important role of this age class in the epidemiology of the virosis in the tested populations. Moreover, the study confirmed that wild boar can be a host of PCV-2, and showed that the virus and PMWS is widespread and endemic in wild boar in Italy as in other countries.