Establishment of a typing enzyme-linked immunosorbent assay for foot and mouth disease antigen, using reagents against viruses endemic in Thailand.

Antisera were produced at a central laboratory in Thailand against the endemic serotypes (O, A and Asia 1) of foot and mouth disease (FMD) virus. At a regional veterinary laboratory, these antisera were used in an indirect sandwich enzyme-linked immunosorbent assay (ELISA) for the detection and serotyping of FMD virus (FMDV) antigen. ELISA readings of < 0.10 optical density (OD) units were considered negative. This was verified using fifty tissue samples which were known to be negative for FMDV. The highest mean sample value for three different dilutions was 0.02 OD units. Of a total of 93 samples submitted for antigen typing, 80 (86%) tested positive by ELISA and 13 (14%) were negative. No FMDV was detected in ELISA-negative samples following attempted tissue-culture virus isolation.