Aujeszky's disease (AD) is increasing in Europe and it has become a serious problem in some of the countries of the European Communities (EC). The control and eradication of the disease is very difficult since AD virus (ADV) evokes a persistant latent infection in its main host, the pig. Such latent infection can also occur when vaccinated pigs are exposed to the virus. In view of this, the Commission of the European Communities (CEC) thought it necessary to have a survey on the current state of knowledge on AD and ADV. Therefore, a seminar was organised by the Federal Research Institute for...