[Control of enzootic Aujeszky's disease on pig farms]

Virologic and serologic investigations were carried out to demonstrate the persistence of the virulent virus of Aujeszky's disease. Threefold vaccinations were conducted with a live vaccine, embracing all animals on the farm and those that were born during the time when sanitation measures were applied. The first vaccination of the sucking pigs was performed with 10 doses of the vaccine in each case. During the time of applying sanation measures the farm was kept closed, the pigs after weaning being transferred to another farm. After sanitation was over some new virologic and serologic studies were carried out along with the serologic examination of nonimmune pigs that had stayed on the farm. These investigations did not prove the presence of a wild virus on the farm. It was found that the manifold vaccinations and use of higher amounts of the vaccine might well suit the base in working out sanitation programmes for farms infected with Aujeszky's disease.