Abstract
Borna disease virus, an unclassified infectious agent, causes immune-mediated neurologic disease in a wide variety of animal hosts and may be involved in pathogenesis of selected neuropsychiatric diseases in man. Initial reports suggested that Borna disease virus is a single-stranded RNA virus. We describe here a method for isolation of viral particles that has allowed definitive identification of the genome as containing a negative-polarity RNA. Further, we show that the viral mRNAs are transcribed in the nucleus.