Equis ISSN 2398-2977

Neurology: Borna disease

Synonym(s): Near Eastern Equine Encephalitis (NEEE)

Contributor(s): Caroline Hahn, Graham Munroe

Introduction

  • A rare, sporadic, severe neurological disease occurring in spring and early summer.
  • Cause: Borna disease virus (BDV) - classified by itself in theBornaviridaefamily.
  • Signs: abnormal mentation; compulsive behavior; circling; head pressing; depression; tremors; hyperesthesia; often progresses to convulsions or coma. 
  • Diagnosis: neurological examination; antibody testing of CSF and serum.
  • Treatment: symptomatic care.
  • Prognosis: grave high mortality; residual neurological deficits are common, necessitating euthanasia.

Pathogenesis

Etiology

  • Caused by Borna disease virus (BDV).
  • Cell-free virus has still to be isolated for full virology to be possible.
  • Route of infection is unknown - ? inhalation, ingestion, tick-borne.

Pathophysiology

  • Low morbidity.
  • The specific etiology of the development of the clinical disease is unknown, but thought to be the result of a virus-induced, cell-mediated, immunopathological reaction.
  • The virus can produce latent or persistent infections, or asymptomatic carrier states which may excrete the virus and be a potential risk to others.
  • High mortality around 80%.

Timecourse

  • A long incubation period of 4 weeks to 6 months before clinical signs.
  • Acute encephalitis phase usually lasts 1-3 weeks.
  • Full recovery is rare.

Epidemiology

  • Route of infection is unknown - ? inhalation, ingestion or tick-borne.
  • Cases are usually sporadic.
  • In-contacts or recovered animals may become asymptomatic carriers which can excrete the virus indefinitely.
  • ? Wild birds are implicated in transmission of the disease between populations.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Priestnall S Let al(2011)Borna disease virus infection of a horse in Great Britain.Vet Rec168(14), 380 PubMed.


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