Borna Virus
Borna-Disease-Virus (BoDV-1)
Profile
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 so far only been detected in animals in isolated cases – since 2015, seven cases of Borna disease have been detected in horses.
No cases of encephalitis caused by bornaviruses have yet been reported in humans in Austria. In Germany, infections in humans with the classical bornavirus (BoDV-1) were first detected in 2018, leading to Borna disease being classified as a zoonosis.
Technical information
Shrews are considered to be the reservoir hosts for the classical bornavirus (Borna disease virus, BoDV-1): they carry the virus for their entire lives without falling ill themselves. Over the past ten years, numerous new bornaviruses have been discovered in birds and reptiles, which must be clearly distinguished from the pathogen responsible for Borna disease in horses. These include the squirrel bornavirus (VSBV-1), which was described in Germany in 2015 among breeders of chipmunks as the cause of central nervous system disorders.
Borna disease (BD) was first described in 1813. It got its name when, in 1894, a large number of cavalry horses fell ill in the town of Borna in Germany. In addition to horses, sheep also frequently contract BD in endemic areas. More recently, cases have also been reported in dogs, cats, cattle, goats, New World camelids and monkeys (experimentally). Since autumn 2022, several detections have been reported in hedgehogs in Borna endemic areas of Germany; the test results suggest that hedgehogs may also act as accidental hosts. In Austria, Bornavirus was detected for the first time in a hedgehog in 2026 in a known endemic area in Upper Austria.
Cases of the disease in domestic animals in Austria are very rare: in the 1990s, there were two cases in horses and one case in a dog in Vorarlberg. Vorarlberg is considered an area where the classical 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. According to information from the Friedrich-Loeffler Institute, a case was detected in 2020 in a German laboratory in a horse from the same region of Upper Austria. In 2026, Bornavirus disease with progressive CNS symptoms was again detected in two further horses (one of which had been transferred to Lower Austria) in the known endemic area of Upper Austria.
Clinical symptoms in animals include behavioural changes, movement disorders, compulsive movements, empty chewing, a lowered head posture, teeth grinding, nervousness and, in the terminal stage, inability to rise. Similar symptoms can be caused by other encephalitis pathogens such as West Nile virus, TBE virus, Japanese encephalitis virus, the pathogens responsible for so-called American encephalomyelitis or rabies, as well as by various forms of poisoning.
Although Borna disease is a zoonosis, it is not currently classified as a notifiable animal disease under the Animal Health Act (AHL). In cases of clinical suspicion of encephalitis, or in cases of progressive forms with a poor prognosis or a fatal outcome, blood samples or CNS tissue from the affected animals should nevertheless be sent to the National Reference Laboratory for further investigation. Due to the zoonotic potential of most of the pathogens to be considered in the differential diagnosis, the head (in accordance with biosecurity measures) should be removed and sent in for this purpose.
Contact
Institut für veterinärmedizinische Untersuchungen Mödling
- vetmed.moedling@ages.at
- +43 50 555 38112
-
Robert Koch-Gasse 17
2340 Mödling
Last updated: 23.06.2026
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