Figure 4From: Congenital infection with atypical porcine pestivirus (APPV) is associated with disease and viral persistence NS3 blocking ELISA results of farm A. The relative signal of the mAb 1B3 is depicted after blocking with porcine sera. Blocking with FCS was used as a reference. Sera of unsuspicious sows and piglets from unaffected farms showed relative intensities >50%. Seroconverted sows that had given birth to APPV infected piglets and their CT-affected piglets have a strong serum blocking activity with signal intensities <30%. The specificity of the ELISA reaction was validated by IF staining of cell expressing APPV-NS3H (Additional file 3). The ELISA intensities of all sows and boars of farm A are shown to demonstrate the mixed reactivity within this affected herd. In addition, the ELISA values of 14 sows, which had a litter with well-documented APPV positive CT cases, are presented separately. The sows with APPV associated CT-litters exhibit a stronger reactivity in the blocking ELISA on average. Using a cut-off value of 50% the seroprevalence in farm A reached 35% (60/170).Back to article page