Bluetongue virus RNA detection by RT-qPCR in blood samples of sheep vaccinated with a commercially available inactivated BTV-8 vaccine

In 2008, a country-wide bluetongue virus 8 (BTV-8) vaccination campaign has been initiated in Austria, using a single commercial inactivated BTV-8 vaccine. Based on preliminary data, we hypothesised that vaccine-derived BTV RNA is transiently detectable by reverse transcription quantitative real-time PCR (RT-qPCR) in the blood of vaccinated animals. Thus BTV-8 vaccine was administered to five BTV-naïve adult sheep and blood samples were taken at various time-points post-vaccination. BTV RNA was detectable by several RT-qPCR methods in all five animals, mainly within the first 9 days post-vaccination. These results show that RT-qPCR based testing for BTV-infection may be influenced by vaccination with certain inactivated BTV-8 vaccines.