The foot-and-mouth disease virus (FMDV) is the pathogen that causes foot-and-mouth disease. It is a picornavirus, the prototypical member of the Aphthovirus genus. The disease, which causes vesicles (blisters) in the mouth and feet of bovids, suids, ovids, caprids and other cloven-hoofed animals is highly infectious and a major plague of animal farming.