Control measures directed at Aujeszky's disease virus: a theoretical evaluation of between-farm effects

Abstract A state-transition model of between-farm spread of Aujeszky's disease virus(DV) was studied using simulations, the basic reproduction ratio approach and economic calculations. In the model, each farm has one of 40 (2×4×5) states, indicating: (1) whether a herd is a breeding or finishing operation; (2) one of four infection levels; (3) one of five protection levels. The basic reproduction ratio calculations, which are based on some (probably) reasonable parameter estimates, lead to the conclusion that only vaccinating both breeding herds and finishing herds will eradicate ADV from the Dutch population. This vaccination strategy is economically profitable if the disease-free period after eradication lasts for more than 35% of the time needed for eradication (assuming the same parameter values). Moreover, even when eradication fails, vaccinating both breeding and finishing herds seems profitable. Obviously, to apply this model correctly, more information is needed on what actually happens on different types of farms when applying various vaccination and/or removal strategies.