Fig. 5

Detection of anti-RVFV IgG antibodies in sheep sera by ELISA using plant-produced N-protein. Animal serum samples 1–20 represent PP values calculated for RVFV-negative sera (blue dots) and samples 21–40 represent PP values calculated for RVFV-positive sera (orange dots). The error bars illustrate ± mean standard deviation calculated from each PP value. The cut-off value (grey line) to distinguish between positive and negative test outcome in IgG capture ELISA was calculated as the percentage of high-positive control serum (PP) values greater than 7.0. PP values less than 4.0 are regarded as negative and PP values between 4.0 and 7.0 are regarded as suspect