Borna disease

Borna disease, also known as sad horse disease, is an infectious neurological syndrome of warm-blooded animals, caused by Borna disease viruses 1 and 2 (BoDV-1/2). BoDV-1/2 are neurotropic viruses of the species Mammalian 1 orthobornavirus, and members of the Bornaviridae family within the Mononegavirales order.

Borna disease is a severe neurological illness that predominantly affects horses and sheep, but it has been observed in a wide range of mammals. The disease is characterised by ataxia and abnormal depressive behaviour, frequently culminating in death. There have been rare cases of human fatalities associated with encephalitis caused by Borna disease virus infection. Additionally, correlative evidence exists linking BoDV-1/2 infection with neuropsychiatric disorders such as bipolar disorder in humans.