Absence of BVDV infection in free-ranging ungulates supports BVD-free status in northeastern Germany.

Bovine viral diarrhea virus (BVDV) is a major pathogen of cattle worldwide, for which control programs have been implemented in several countries. In Germany, long-term compulsory eradication measures have resulted in a marked decline of BVDV prevalence. Numerous federal states, among them Mecklenburg-Western Pomerania, have achieved an official BVD-free status in domestic cattle. As wildlife may represent a potential source of virus reintroduction, this study investigated the occurrence of pestiviruses in free-ranging ungulates in this federal state between 2023 and 2025. Blood samples and nasal swabs from 909 animals, including roe deer, red deer, fallow deer, mouflon and wild boar, were analyzed using serological and molecular methods. All blood samples tested negative for antibodies against ruminant pestiviruses, and all ruminant nasal swabs were negative in two independent pan-pestivirus RT-PCR assays. One wild boar sample, however, tested positive by RT-PCR and the atypical porcine pestivirus (APPeV) was identified. The results provide evidence that free-ranging ungulates do not play a significant role in maintaining BVDV in regions, where the virus has been eradicated from domestic cattle. Nevertheless, sustained surveillance of wildlife remains important, particularly in regions with high wildlife density and close interactions between wildlife and livestock, to ensure early detection of potential reintroduction events or emerging pestiviruses, such as APPeV.