Polymerase chain reaction was the most widely use nucleic-acid-based diagnostic techniques since its invention [141, 142] . With the development of RT-PCR to amplify RNA targets many workers have assessed the usefulness of it as a reliable tool for FMD diagnosis [29, 30, 32, 33] and in parallel with conventional assays [34, 143, 144] . A particularly high sensitivity was reported by RT-PCR ELISA [143, 145] . A specific RT-PCR was developed and validated for the detection of the polymerase gene (3D) of FMD with an analytical sensitivity equal to 1000 times higher than that of a single passage virus isolation [146] . In a study to compare the sensitivity of assays for the diagnosis of FMD, a cell suspension plaque test on BHK21-CT cells and a reverse transcription nested PCR (RT-nPCR) were used to examine nasal swabs and probang samples obtained from FMDV infected cattle, it has been observed that examination of nasal swab revealed a higher number of infected animals using RT-nPCR than by the used the plaque tests and for probang samples both test gave approximately equivalent result [147] . PCR products generated have currently only been analyzed by gel electrophoresis exposing to the chance of post-PCR contamination. However PCR offers potential advantages over other conventional tests. The risk of false negative associated with poor sample handling is limited. Because virus, if present, would be inactivated by RNA extraction, it would be acceptable to use lower level biosafety. Further, cell culture loses the sensitivity due to presence of inhibitors like interferons and presence of some enzymatic inhibitors. Several studies have compared Reverse Transcription (RT-PCR) methods with FMDV isolation [35, 143, [147] [148] [149] . The sensitivity of the methods reach similar to or greater than virus isolation techniques and these can supplement or go in parallel, but not replace, the routine procedures for diagnosis of FMDV. Detection of all seven serotypes of the virus with each of the serotype specific primers in selected RT-PCR protocols at OIE/FAO World Reference Laboratory for FMD (WRL), Pirbright demonstrated suitable specificity and detected cell culture passage isolate with some success but were not adequate for the serotyping of suspension prepared from clinical samples of epithelium. RT-PCR though has paved the way to more sensitive and rapid test in the field of molecular diagnosis, serotyping of FMDV has been of difficult and this has been solved with the advent of multiplex PCR (mPCR).