Occurrence of bluetongue virus in the population of animals imported to Poland from EU member states

The aim of this study was to determine the prevalence of bluetongue virus (BTV) in the blood of susceptible animals, tested in the frame of the BT national monitoring programme. The rRT-PCR assay was applied to virological examination of animals imported from BT-affected countries. On December 5, 2007, the BTV RNA was detected for the first time in blood samples of seropositive cattle from Germany. So far, the presence of the RNA was detected in 37 samples of blood collected from German cows and in one sample taken from Dutch fallow deer. The presence of viral RNA was also found in the blood taken from a 4-week-old calf born from BT positive dam imported from Germany. It was an evidence of the vertical transmission of BTV. The long persistence of BTV in blood of infected animals was demonstrated. The viral RNA was detectable as long as one month after the first collection. Taking into consideration the above results, the implemented virological monitoring tests, in parallel with the surveillance studies, should be continued to monitor the actual BT status in Poland.