A long-term survey of pseudorabies virus infections in European wild boar of western Germany

In a long-term study, a total of 1,112 European wild boar (Sus scrofa) shot in the southern part of North Rhine Westphalia between 1993 and 2000 were investigated for the infection with pseudorabies virus (PRV). Of 929 sera tested during the 7 year observation period -92 (9.4%) had PRV-specific antibodies with an overall seroprevalence in the south west of North Rhine Westphalia of 11.4%. A total of 473 tissues and 516 mucosal swabs collected between 1996 and 2000 from wild boar originating from those districts were tested for the presence of PRV using virus isolation in cell culture. In 2000, 4 viruses were isolated from the tonsils of piglets and juvenile wild boar shot in the district of Bonn, which were identified as type Ip PRV. When tonsils and lungs were additionally tested in a glycoprotein D-specific PCR, 14 (4.0%) and 2 (1.6%) were positive. Virus isolation and PCR results suggest that PRV might be mainly transmitted by wild boar piglets. The results also indicate that PRV-infections have been endemic in wild boar populations in the south west of North Rhine Westphalia for several years. Based on present knowledge, the area covered by this study appears to be part of a larger, coherent endemic area comprising wild boar populations in neighbouring re ions of western Germany. Recently, PRV was eradicated in the domestic pigs in North Rhine Westphalia resulting in a recognition as an officially Aujesky's disease free region within the EU. As in other regions, so far, PRV infections in the wild boar population appear not to affect the domestic pig population.