ABSTRACT

Aujeszky's disease (AD, pseudorabies) eradication programs in domestic pigs are implemented in several European countries where AD virus (ADV) circulates in local wild boar (Sus scrofa), making studies on ADV infection dynamics in wild boar increasingly relevant. The objective of our study was to characterize ADV dynamics in wild boar at a site in central Portugal and compare this site to three enzootic sites in central Spain. A total of 235 wild boar were sampled during the hunting season 2014–15. We collected serum, tissues (oropharyngeal tonsils and trigeminal and sacral ganglia), and swabs (oral, nasal, and genital) and analyzed these samples to detect ADV antibodies (enzyme-linked immunosorbent assay) and DNA (PCR). An overall seroprevalence of 42.6% was found (range 12.7–57.7%), being highest in adults (54.1%; 72/133). Overall, 2.8% (3/108) oral, 6.4% (7/109) nasal, and 12.8% (12/94) genital swabs were PCR positive. We found 20.4% (20/98) of the wild boar had at least one positive swab and were considered shedders. We found ADV in tissues of five animals; of 111 tonsils, three (2.7%) were PCR positive. Trigeminal (2/48; 4%) and sacral (2/53; 4%) ganglia collected in central Portugal, pertaining to three animals, were positive for ADV DNA. Logistic regression models showed that seroprevalence was influenced by site and age, whereas ADV shedding was influenced by site. Our study describes patterns of ADV infection in wild boar in Portugal and shows that wild boar also pose a risk, albeit lower than that in central Spain, for the eradication of AD from extensively managed domestic pigs in Portugal.

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