Characteristics in the epidemiology of bovine viral diarrhea virus (BVDV) of relevance to control.

An understanding of the driving forces of BVDV transmission can be gained by considering the reproductive rate, between individuals and between herds. The former determines the prospects for eliminating the infection from herds, and the latter is the key to persistence at the population level. In this paper, the relation between these two characteristics, their underlying parameters and measures and priorities for BVDV control are discussed. A general model for BVDV control is outlined, with bio-security, virus elimination and monitoring as three necessary consecutive elements, and with immunization as an optional step. A distinction is made between systematic and non-systematic approaches to BVDV control (where the former refers to a monitored and goal-oriented reduction in the incidence and prevalence of BVDV infection and the latter to where measures are implemented on a herd-to-herd decision basis and without systematic monitoring in place). Predictors of progress for systematic control approaches in general are discussed in terms of the abilities: to prevent new infections, to rapidly detect new cases of infection, to take action in infected herds and to gain acceptance by stakeholders. We conclude that an understanding not only of the biology, but also of the social factors - human behavior, the motives that makes stakeholders follow advice and the cultural differences in this respect - are important factors in forming recommendations on alternative strategies for BVDV control.