[Elimination of persistently BVDV infect animals: efficient herd screening using RT-PCR and antigen ELISA in milk and...

With the long-term perspective of the eradication of BVD/MD in the German federal state Saxony-Anhalt a voluntary control program was initiated in 2002 by an administrative regulation based on federal German guidelines. The short-term aim of this program is the establishment of BVDV-unsuspected herds achieved by elimination of persistently infected cattle. The diagnostic program and particularly the choice of the diagnostic tools was based on the consideration of laboratory experiences as well as on economic and logistic aspects. A combination of RT-PCR and antigen-ELISA was found to be the suitable diagnostic methods. The screening started with examinations of sera pools using Real Time RT-PCR in the Light-Cylcer system. After positive pool results the individual persistently infected animals were detected using various commercial ERNS-antigen-ELISAs. The RT-PCR revealed a high degree of sensitivity and robustness. With respect to highly specific ELISAs the producers have to ensure the detection of all currently important virus strains. The prevalence of persistently infected animals in the cattle population of Saxony-Anhalt was about 0.2% during the last 3 years. This is probably due to nearly 10 years of broad vaccination and will prove advantageous for BVDV elimination.