Several cases of human illness with symptoms suggestive of Aujeszky's Disease (AD) at an outbreak of the disease in cattle and swine were evaluated during this study. Additionally serological studies of people in the group at high risk for illness caused by Aujeszky's Disease Virus (ADV) were carried out. In a herd of 180 bulls sudden clinical disease occurred with symptoms of muscular tremors, salivation, sweating and severe pruritus of the head. The clinical disease lasted two to eight hours and finished in death. In 7 days 10 bulls died and 60 were either killed or culled. A biological test for AD was positive. ADV was identified in the brain of a dead bull. Serological studies for the bulls were negative, however 92.9% on the premises farm were asymptomatically infected. On third to the fifth day of disease in the cattle clinical signs appeared in six of seven workers which had direct contact with diseased cattle. A pruritus of the palms, which spread onto the lower and upper arms, shoulders and back lasted several days.