Serosurvey of Aujeszky's disease virus in the Swiss wild boar population

Abstract

In parallel to the control programs for Aujeszky’s Disease (AD) in domestic pigs in Europe, a prevalence increase of AD virus (ADV) infection has been observed in wild boar (Sus scrofa). Furthermore, AD cases have been reported in hunting dogs after contact with wild boar. In Switzerland, domestic pigs are AD-free. A serosurvey performed in wild boar in 2004/2005 had revealed a prevalence of 2.8% (95% confidence interval CI: 1.9-4.0%). Considering the locally increasing wild boar abundance and assuming that ADV prevalence may be density-dependent, we wanted to re-estimate the ADV seroprevalence in Swiss wild boar. As this study is part of a European project (APHAEA) with the aim to harmonize procedures in wildlife health investigations, we used the same diagnostic test as previous ADV serosurveys in Spain and Germany. So far, 945 serum samples from free-ranging wild boar collected over 5 hunting seasons (2008-2012) from 5 different study areas in Switzerland were included in this study. Samples were analyzed by a commercial ELISA kit (IDEXX PRV/ADV gI Ab Test) for detecting antibodies against Suid Herpesvirus-1. An overall prevalence of 0.7% (95% CI: 0.3-1.5) was obtained, with additional 6.1% doubtful samples that will be retested. These preliminary data indicate that the prevalence of ADV infection in the Swiss wild boar population has remained low so far and that the influence of animal density on AD prevalence is less important than originally assumed.