Borna disease virus: a mystery as an emerging zoonotic pathogen.
Authors: Richt J A, Rott R
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary: Borna Disease Virus as an Emerging Zoonotic Threat Borna disease virus (BDV), a negative-sense RNA virus in the family Bornaviridae, represents a significant but poorly understood threat to equine and other animal populations, particularly across Central Europe where it has been documented for decades as a cause of progressive viral polioencephalomyelitis with devastating neurological consequences. Clinical infection typically emerges after an incubation period of weeks to months, manifesting as characteristic behavioural disturbances, locomotor and sensory dysfunction, progressing to paralysis and death, though natural infections often remain subclinical and go undetected. BDV's zoonotic potential gained international concern when antibody evidence suggested human susceptibility alongside a broad range of domestic and wild animal species, raising questions about occupational exposure risks for equine professionals and animal handlers. However, the presence of active viral markers (RNA or antigen) in human neuropsychiatric patients remains highly controversial and inconsistently documented, making definitive claims about human pathogenicity premature and highlighting critical gaps in our understanding of transmission and clinical significance. For practitioners, this means maintaining awareness of BDV as a differential diagnosis in horses presenting with unexplained neurological or behavioural problems—particularly in endemic regions—whilst recognising that the human health implications, though scientifically interesting, remain unproven and should not drive clinical decision-making.
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Practical Takeaways
- •Horses and sheep presenting with progressive neurological signs, behavioural changes, and paralysis should be investigated for Borna disease as a differential diagnosis, particularly in Central Europe
- •While BDV has zoonotic potential based on serological evidence in humans, the presence of active virus in human neuro-psychiatric patients remains unconfirmed and controversial
- •Veterinarians should be aware that most natural BDV infections may be subclinical, complicating diagnosis and potentially allowing asymptomatic transmission among susceptible animals
Key Findings
- •Borna disease virus (BDV) is a negative-sense, single-stranded RNA virus in the family Bornaviridae that causes progressive polioencephalomyelitis in horses, sheep, and other domestic and zoo animals
- •BDV infection causes severe clinical signs of viral encephalitis with striking behavioural disturbances after an incubation period of weeks to months, progressing to paralysis and death
- •Natural BDV infections are subclinical in most cases, but BDV-specific antibodies have been detected in sera and cerebrospinal fluid from neuro-psychiatric patients, raising questions about zoonotic potential
- •Reports of BDV-RNA or BDV-antigen in peripheral blood leukocytes or brain tissue of neuro-psychiatric patients are highly controversial, making the role of BDV in human disease questionable