Diagnosis of Feline Herpesvirus Infection by Immunohistochemistry, Polymerase Chain Reaction, and in Situ Hybridization:

An adult domestic shorthair cat had severe chemosis due to purulent and necrotizing blepharitis and conjunctivitis. Purulent rhinitis, necrotizing glossitis, and dermatitis were also diagnosed. The cat was positive for feline immundeficiency virus and feline leukemia virus. Histologically, intranuclear Cowdry type A inclusions were found within numerous epithelial cells adjacent to the lesions in skin, conjunctiva, and tongue. Electron microscopic examination revealed herpesviral particles within the lesions. Paraffin-embedded skin and tongue tissues were processed in a polymerase chain reaction, using primers to amplify a 306-bp region of the thymidine kinase gene of feline herpesvirus type 1, resulting in a distinct amplification product of the predicted size. The distribution of feline herpesvirus was demonstrated by immunohistochemistry and nonradioactive in situ hybridization. Positive immunostaining was found in nuclei and cytoplasm of numerous epithelial cells within and next to the lesions, wherea...