Abstract
A 15-year-old cat was referred to us with acute disorder of the limbic system and brain stem. Magnetic resonance imaging (MRI) and other clinical examinations revealed extensive encephalitis from the olfactory bulb to the midbrain. The cat was euthanased because of the severity of the disease. Histologically, the lesion observed by MRI was diagnosed as Cryptococcus encephalitis. Since the cat was positive for Burna disease virus (BDV), the brain was stained immunopathologically. Antigen to BDV was detected in the cerebellum, the pons, and the medulla oblongata, where no inflammatory response to Cryptococcus had been seen. Consequently, the cat was considered to have been infected with both Cryptococcus (Neoformans) and borna virus.
