Serology. The animals were vaccinated 6 and 2 weeks before challenge. Bars represent one animal each. Serum samples were tested by a commercially available SBV antibody ELISA (A) and in standard microneutralization tests against SBV (B), AINO (C) and AKAV (D). Horizontal dashed lines indicate the cut-off value of the respective test. The neutralization titers are expressed as reciprocal of the serum dilution showing 50% virus neutralization.