Diagnosis of Aujeszky's disease virus infection in dogs by use of immunohistochemistry and in-situ hybridization.

Aujeszky's disease (AD) was diagnosed in seven dogs by histological examination, immunohistochemistry and DNA in-situ hybridization. All dogs which lived on two swine farms died spontaneously showing an acute neurological syndrome (hypersalivation, vomiting, pruritus, depression and coma). The most significant histopathological lesion was a non-suppurative encephalitis located in the brain stem, mainly near the floor of the IVth ventricle. Aujeszky's disease virus (ADV) antigen and ADV nucleic acid distribution coincided with the histopathological lesions. However, little ADV antigen and ADV nucleic acid was found in severely damaged areas. A few neurons stained intensely by immunohistochemistry and in-situ hybridization in non-inflammatory areas. Both immunohistochemistry and in-situ hybridization techniques are valid techniques to confirm ADV infection in paraffin-embedded tissues and will be useful for characterizing the pathogenesis of ADV in the central nervous system (CNS) in carnivores.