Interference of vaccination against bluetongue virus serotypes 1 and 8 with serological diagnosis of small-ruminant lentivirus infection.

The effects of the recent vaccinations against bluetongue virus serotype 1 (BTV-1) and BTV-8 in Europe on the reliability of enzyme-linked immunosorbent assays (ELISAs) currently used for diagnosis of small-ruminant lentivirus (SRLV) infection were examined. Primary vaccination against BTV-8 in goats induced an increase in reactivity that did not exceed 3 months in a whole-virus indirect ELISA and a competitive ELISA based on the gp135 glycoprotein. Subsequent BTV-1/8 vaccination extended the time scale of false-positive reactivity for up to 6 months. These results are of relevance for SRLV-monitoring programs.