 PIs act as viral reservoirs and are the principal source of viral infection but transiently infected animals and contaminated fomites also play a significant role in transmission.Leading the way in BVD eradication, almost 20 years ago, were the Scandinavian countries.Despite different conditions at the start of the projects in terms of legal support, and regardless of initial prevalence of herds with PI animals, it took all countries approximately 10 years to reach their final stages.