NEUROLOGICAL DISEASE AND ENCEPHALITIS IN CATS EXPERIMENTALLY INFECTEDWITH BORNA-DISEASE VIRUS

Barrier-bred cats were inoculated intracerebrally with either the rabb it-adapted Borna disease virus (BDV) strain V or a newly isolated feli ne BDV, obtained from a cat with natural staggering disease (SD). Thre e out of eight inoculated cats developed neurological signs and non-su ppurative encephalitis; all three recovered from the acute stage of di sease. Sere-conversion and the development of neutralizing antibodies occurred in all of the virus-inoculated cats. In addition, cats inocul ated with feline BDV showed an early peripheral T cell response not pr esent in cats inoculated with BDV strain V, suggesting that the feline virus exerted a more vigorous effect on the immune system. Using immu nohistochemistry and a reverse transcriptase-polymerase chain reaction assay, BDV-specific antigen and nucleic acid could be demonstrated in brain samples from each cat with encephalitis, showing that incomplet e viral clearance was probably responsible for the maintenance of infl ammation. The successful induction of neurological signs and encephali tis in one cat infected with feline BDV, together with the detection o f BDV-specific antigen and nucleic acid in the brain, provides strong evidence for the notion that BDV is the etiological agent behind felin e SD.