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.

In parts of Eastern and Southern Germany, Austria, Switzerland and Liechtenstein

Shrews

Via urine, faeces and saliva

Horses show behavioural changes, movement disorders, compulsive movements, empty chewing, lowered head posture, teeth grinding, frightfulness, in the final stage lying down.

There is no therapy

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 reservoir of the classical Borna disease virus (Borna disease virus, BoDV-1): they carry the virus throughout their lives without becoming ill themselves. Over the past ten years, numerous new bornaviruses have been discovered in birds and reptiles that can be clearly distinguished from the pathogen that causes Borna disease in horses. These include the Borna virus of squirrels (VSBV-1), which was described in Germany in 2015 as the cause of central nervous diseases in breeders of coloured squirrels.

Borna disease (BD) was first described in 1813. It was given its name when a large number of cavalry horses in the town of Borna in Germany fell ill in 1894. In addition to horses, sheep also frequently contract BD in endemic areas. Recently, cases have also been reported in dogs, cats, cattle, goats, New World camelids and monkeys (experimentally).

Cases of disease in animals in Austria are very rare: In the 1990s, there were two cases in horses and one case in dogs in Vorarlberg. Vorarlberg is considered an area in which the classic Bornavirus is endemic. In 1998, a single case was diagnosed in a horse in Styria. In 2015 and 2016, four horses fell ill in a region of Upper Austria.

Clinical symptoms in animals include behavioural changes, movement disorders, compulsive movements, empty chewing, lowered head posture, teeth grinding, frightfulness and, in the final stage, lying still. Similar symptoms can be caused by other encephalitis pathogens such as West Nile virus, TBE virus, Japanese encephalitis virus, the pathogens that cause American encephalomyelitis or rabies, as well as various types of poisoning.

Although Born's disease is a zoonosis, it is not currently a notifiable animal disease according to the AHL. If encephalitis is clinically suspected or in the case of progressive forms with an unfavourable prognosis or a fatal outcome, blood samples or the CNS of the affected animals should nevertheless be further examined at the National Reference Laboratory. Due to the zoonotic potential of most of the pathogens to be considered for differential diagnosis, the head should be removed and sent in (in compliance with biosecurity measures).

In Austria, no case of inflammation of the brain (encephalitis) caused by Bornaviruses has yet occurred in humans. In Germany, infections of humans with the classic Bornavirus (BoDV-1) were detected for the first time in 2018.

Information from the Robert Koch Institute

Information from the Friedrich Loeffler Institute