A quarantine period for potentially contaminated personnel can be used to reduce the risk of transfer of foot-and-mouth disease virus (FMDV) from infected to susceptible premises. This is set at 72 hours in the UK, on the basis of results from laboratory studies and field observations. Previous analysis of FMDV carriage within human nasal cavities has relied upon virus isolation by culture in susceptible cells. This study, involving 51 people, evaluated a PCR method, which detected viral genomic material within 35 nasal swabs taken from personnel after up to eight hours exposure to infected animals. Only one of 23 people who was PCR-positive immediately after exposure to FMDV-infected animals remained positive the following day, indicating a low risk of prolonged carriage of virus in the nasal cavities.