The possibility of vaccination was first permitted in 2000, but was subject to strict rules since untreated animals could also have been infected by the viruses through the vaccine.
Posibilitatea vaccinării a fost permisă pentru prima dată în 2000, dar aceasta a fost supusă unor reguli stricte, deoarece animalele netratate ar fi putut fi infectate, de asemenea, de virusuri prin intermediul vaccinului.