[Possible methods of control of virus disease in swine today and in the future (author's transl)].

To begin with, possible approaches to the control of virus disease in swine are discussed in general. The choice of a method of control will be decided by various factors such as the ecological and geographical environment of the animal population, the epizootiological behaviour of the causative virus itself as well as economic and political considerations. These consist in definitely freeing the swine population and/or keeping it free from a particular virus, maintaining a particular virus in an enzootic state, promoting this enzootic state within the herd, vaccinating and, finally, combining the above procedures. In conjunction with the trend towards increasingly large piggeries, the equilibrium between natural or specific immunity of the animal population and various viruses is often upset to the advantage of the virus. The pressure of infection will increase unduly and the epizootiological behaviour of the virus in question will not infrequently undergo alterations. Therefore, it is believed that the need for artificially increasing immunity or maintaining it at its current level will constantly increase in the long run. This can only be achieved by frequent vaccination. It is not unlikely that vaccination will remain as the sole and last possibility of effectively controlling various forms of virus disease in pigs.