EVALUATION OF PRIMERS FOR PCR AMPLIFICATION OF RNA-POLYMERASE GENE-SEQUENCES OF FOOT-AND-MOUTH-DISEASE VIRUS

Eight oligonucleotide primers in 7 different combinations were used to amplify 3D gene sequences of foot-and-mouth disease virus (FMDV) by r everse transcription-polymerase chain reaction (RT-PCR). Six of the pr imers were designed at this laboratory. All the primer combinations co uld specifically amplify 3D gene sequences of FMDV serotypes O, A, and C. The largest fragment amplified was of 1,393 bp and the smallest wa s of 208 bp in size. The 1,393 bp fragment included sequences from the preceeding P18 region of FMDV genome. The second largest fragment of 734 bp included sequences from the 3'-extracistronic region of viral g enome. The remaining fragments were amplified either from the 3'- or 5 '-half of the 3D gene. Specific amplification of the entire 3D gene in fragments of different size showed sequence conservation in the 3D ge nomic region of FMDV and usefulness of the primers reported in detecti ng inapparent or persistent FMDV infection in susceptible animals by R T-PCR.