[Use of an immunoenzyme histochemical method for the improvement of the etiologic diagnosis of Aujeszky's disease in swine].

With regard to the legal regulations for the diagnosis of Aujeszky's disease in pigs, a retrospective immunoenzymatic study was performed on brains of 20 pigs, in which Aujeszky's disease had been diagnosed based only on clinical, macroscopical and histological findings, although the etiological agent could not be demonstrated neither by immunofluorescent technique nor by virological cultivation. Applying the peroxidase-antiperoxidase-(PAP) method, in 6 of 20 animals (30%) viral antigen of porcine herpesvirus type 1 was demonstrated in situ in at least two of five different locations of the brain. Reasons for negative results in immunohistological and virological investigations are discussed and the significance of the performed immunoenzymatic technique is pointed out.