either [(a) has been free for 12 months from foot-and-mouth disease, rinderpest, African swine fever, classical swine fever, swine vesicular disease, and]
o bien [a) ha(n) estado doce meses indemne(s) de fiebre aftosa, peste bovina, peste porcina africana, peste porcina clásica y enfermedad vesicular porcina, y]