Vaccination induces long-lasting neutralising antibodies against bluetongue virus serotypes 1 and 8 in Spanish ibex (Capra pyrenaica)

Bluetongue virus (BTV) is the causal agent of bluetongue (BT), a disease of wild and domestic ruminants. Even though control strategies have been used in livestock in Europe, BTV still persists in wild ruminant populations. Twenty-two out of 90 Spanish ibexes (Capra pyrenaica) received a single subcutaneous dose of inactivated vaccine against BTV serotype 1 (BTV-1) and 24 against BTV-8, and the remaining 44 ibexes were used as unvaccinated controls. All the ibexes were seronegative before vaccination and reverse transcription-quantitative PCR (RT-qPCR) negative both before vaccination and at the end of the study. ELISA and serum neutralisation test (SNT) were performed on sera samples at 0, 4, 12, 16 and 28 months post-vaccination (mpv). The unvaccinated ibexes remained seronegative, while BTV-1- and BTV-8-vaccinated groups were seroconverted after vaccination, showing antibody levels until the end of the study that were comparable to those proved to be protective against BTV experimental infection in this species. The results indicate that one dose of vaccine induced BTV-specific neutralising antibodies in Spanish ibex for at least 28 mpv.