Borna disease (also called contagious equine encephalitis) is a viral disease that mainly affects horses and sheep. In the past ten years, numerous new Borna viruses have been discovered in birds and reptiles, which can be clearly distinguished from the causative agent of Borna disease in horses.
Situation in Austria
In Austria, the virus has been detected in animals only sporadically so far - in recent years, 4 cases of Bornasch disease have been detected in horses.
In humans, no case of inflammation of the brain (encephalitis) caused by Bornavirus has yet occurred in Austria. In Germany, infections of humans with classical Bornavirus (BoDV-1) were detected for the first time in 2018, resulting in Bornasch disease being classified as a zoonosis.
Shrews are considered to be the pathogen reservoir of the classic Borna disease virus (BoDV-1): they carry the virus throughout their lives without becoming ill themselves. In the past ten years, numerous new bornaviruses have been discovered in birds and reptiles that can be clearly distinguished from the causative agent of Borna disease in horses. These include bornavirus of squirrels (VSBV-1), which was described as causing central nervous disease in breeders of variegated squirrels in Germany in 2015.
Borna disease was first described in 1813. It received its name when a large number of cavalry horses in the town of Borna, Germany, became ill in 1894. More recently, disease has also been reported in cattle, goats, cats, and monkeys. Cases of disease in animals in Austria are very rare: In the 1990-ies, there were two cases in horses and one case in dogs in Vorarlberg. Vorarlberg is considered an area where classical bornavirus is endemic. In 1998, an isolated case was diagnosed in a horse in Styria. In 2015 and 2016, four horses became ill in a region of Upper Austria. Clinical signs in animals include behavioral changes, movement disorders, forced movements, empty chewing, lowered head posture, teeth grinding, startle, and in the final stage, recumbency. Similar symptoms can be caused by encephalitis agents such as West Nile virus, TBE, Japanese encephalitis virus, or rabies, as well as by various poisonings. In Austria, all clinical forms of encephalitis in horses are notifiable (§16 Animal Diseases Act). Dead/euthanized animals (organs) with suspected encephalitis must be sent to the responsible NRL for equine encephalomyelitis (AGES Mödling).
In humans, no case of inflammation of the brain (encephalitis) caused by bornaviruses has yet occurred in Austria. In Germany, infections of humans with classical bornavirus (BoDV-1) were detected for the first time in 2018, resulting in Borna disease being classified as a zoonosis.
Last updated: 10.10.2023