Development of an inhibition ELISA test for the detection of non-capsid polyprotein 3ABC in viral suspensions destined for inactivated foot-and-mouth disease vaccines.

The use during the last decade of immuno-enzymatic tests based on the detection of antibodies to the non-capsid proteins (NCPs) of foot-and-mouth disease virus (FMDV) to assess viral circulation, irrespective of vaccination, supported the incorporation into the OIE code of the 'free from FMDV with vaccination' category and opened the way to a 'vaccination to live' policy. Eradication programmes in South America include systematic vaccination accompanied by large serosurveys through NCP antibody testing to ensure the absence of residual viral activity. For correct interpretation of serosurveys, a major prerequisite is that vaccines made of semi-purified preparations of inactivated virions do not contain levels of NCPs, which upon proper presentation conditions, could induce an antibody response under the conditions for field immunization.