Foot-and-Mouth disease 'vaccination-to-live': possibilities and constraints.

Major constraints to the adoption of a 'vaccination to live' policy during an outbreak of foot-and-mouth disease (FMD) in a previously FMD-free country are the dual problems in the development of persistent infection (>28 days) in some vaccinated ruminants exposed to virulent virus and reliably detecting these persistently infected animals. Rapid advances in immunology, virology, molecular biology and information management present significant opportunities for improving the management of FMD outbreaks using a variety of scientifically advanced tools without the need for slaughtering large numbers of animals. A more rapid return to FMD-free status should be capable of being achieved without massive slaughter of animals through: (i) improvements in vaccine efficacy, onset of immunity, and marker specificity; (ii) development of anti-viral compounds as an aid in the control of outbreaks with or without vaccination; (iii) improvement of rapid diagnostic tests to detect early infection and persistent infection accurately and (iv) the capture, validation and management of data on animal identification, vaccination and infection status, and movement. The most effective improvements will occur if all these strategies are used in combination.