An enzyme-linked immunosorbent assay (ELISA) for the detection and quantification of antibodies against swine vesicular disease virus (SVDV)

A liquid phase blocking sandwich ELISA has been compared with virus neutralisation for testing pig sera for antibodies against swine vesicular disease (SVD) virus. Highest infectivity titre of SVD virus was obtained using a multiplicity of infection of 30 pfu/cell and harvesting after 21 h. Titres obtained for 300 clinically normal animals were assessed by ELISA and 89% were found to be 1/6 or less. Results were skewed and spread up to 1/45. Comparison of known positive sera resulted in a correlation between the two methods of 0.68 and showed that a virus neutralisation titre of 1/16 was equivalent to 1/40 (log10 1.61) by ELISA. Variation in results obtained by replicate testing using ELISA and virus neutralisation was almost identical. Overlap between positive and negative sera was shown to be reduced to 1-1/2 fold in ELISA. Therefore, the ELISA correlated well with virus neutralisation and has several advantages over the latter.