THE INTERFERENCE BY MATERNALLY-DERIVED ANTIBODY WITH ACTIVE IMMUNIZATION OF FARM-ANIMALS AGAINST FOOT-AND-MOUTH-DISEASE

Foot-and-mouth disease (FMD) is a highly contagious disease affecting ruminants and pigs. In countries in which control of FMD relies predom inantly on vaccination, young stock ingest specific anti-FMD virus ant ibodies in the colostrum. This maternally-derived antibody (MDA) provi des immediate protection against infection with FMD virus, but also in terferes with the development of active immunity following vaccination . However, susceptibility to infection precedes the ability to respond to vaccination in the presence of MDA. Currently available vaccines c annot overcome this inhibitory effect of MDA, and protection of young stock can only be provided by their isolation from FMD virus.