Detection and differentiation of pestivirus antibodies in sheep and suckler cow herds in Southern Germany

Abstract Background Pestiviruses such as bovine viral diarrhea virus (BVDV) or the ovine border disease virus (BDV) are not strictly species-specific and can be transmitted between related animal species. Due to serological cross-reactivity, antibodies against e.g. BDV may interfere with BVDV diagnostics. To assess the impact of non-BVDV pestiviruses on BVDV surveillance during the transition period from virological to serological testing in a region free from BVDV for six years, the presence and type of pestivirus antibodies in sheep and cattle in Southern Germany were investigated. Results Pestivirus antibodies were detected in 15.1% of the examined sheep farms by ELISA and identified as BDV-specific by virus neutralization test. No BVDV-specific antibodies were detected in sheep, consistent with the low prevalence of BVDV in cattle in the investigated region. In cattle, 8.1% of farms and 1.7% of animals were tested positive for pestivirus antibodies by ELISA. Most antibodies were differentiated as BVDV-specific and in those cases, all samples originated from animals that were at least 75 months old, with an average age of 183 months. However, BDV-specific antibodies were detected in six cattle farms. Conclusions BDV seems to be currently the predominant pestivirus in sheep in Southern Germany, while interspecies transmission to cattle appears to be rare. Nevertheless, the presence of BDV-specific antibodies in cattle is relevant for serological BVDV surveillance due to serological cross-reactivity, particularly in the context of declining BVDV seroprevalence.