      borna disease virus is the virus that causes borna disease. == virology == === genome === it has the smallest genome (8.9 kilobases) of any mononegavirales species and is unique within that order in its ability to replicate within the host cell nucleus. borna virus was isolated from a diseased horse in the 1970s, but the virus particles were difficult to characterise. nonetheless, the virus' genome has been characterised. it is a linear negative-sense single stranded rna virus in the order of the mononegavirales. this order contains the family of lyssaviruses which includes the viruses responsible for rabies. a new family named the bornaviridae was created to hold this virus. several of the proteins encoded by the borna virus genome have been characterised. the g glycoprotein is important for viral entry into the host cell. it has 
Bornaviruses Protein_families