Pseudorabies virus in North-West Italian wild boar (Sus scrofa) populations: prevalence and risk factors to support a territorial risk-based surveillance

Although the eradication of Pseudorabies virus (PrV) in domestic pigs is ongoing, the circulation of this virus in wild boars remains a threat in the currently unprotected, 'low prevalence', pig population. In this study, we reported PrV prevalence data and the influence of possible risk factors in 2 North-West Italian wild boar populations (free and enclosed) with the goal of supporting the implementation of a risk-based AD surveillance system. Sera from 1,425 wild boars were collected between 2011 and 2015 and tested by ELISA for the presence of PrV antibodies; the overall raw seroprevalence was 30.39% (433/1,425; CI 95% 28.01-32.85%). A significant difference was however observed between the prevalence rates of the free range population (9.98%; 90/902; CI 95%; 8.10-12.12%) and the enclosed population of La Mandria park (Piedmont, Italy) (65.58%; 343/523; CI 95%; 61.51-69.65%). In both populations a significantly higher number of adults and females were found positive to PrV ELISA. Specific territorial data on PrV circulation in wild boars should be acquired from other regions for guiding risk-based measures in order to reduce the threat of AD re-infection in a more cost-effective manner.