The detection of foot-and-mouth disease virus in oesophageal-pharyngeal samples by a polymerase chain reaction technique.

A polymerase chain reaction (PCR) technique was used to detect the presence of foot-and-mouth disease virus (FMDV) in oesophageal-pharyngeal(OP) samples from experimentally infected steers. Ten-fold dilutions of OP samples were also diluted, inoculated onto lamb kidney cell cultures, and incubated overnight. The cultures that did not show overt cytopathogenic effects (CPE) of FMDV infection were frozen and thawed; both the fluid and the cell pellet were tested by the PCR technique. The PCR detected FMDV in the fluids of 57% of the cell cultures inoculated with 2-20 tissue culture infective doses-50% (TCID50) and of 33% of cell cultures inoculated with the 0.4-2 TCID50. The PCR detected FMDV in cell pellets of all cell cultures inoculated with 20 TCID50, of 71% of cell cultures inoculated with 2-20 TCID50 and of 50% of cell cultures inoculated with 0.2-2 TCID50. A diagnostic scheme using PCR and cell culture that would provide rapid and sensitive detection of FMDV in OP samples is proposed.