Canis ISSN: 2398-2942

Old dog encephalitis

Synonym(s): Disseminated encephalomyelitis in mature dogs, subacute diffuse sclerosing encephalitis, chronic dementional distemper

Contributor(s): Kyle Braund, Simon Platt

Introduction

  • Thought to be the result of infection with canine distemper virus (CDV) Canine distemper disease.
  • There is some speculation that this form of distemper no longer exists as a spontaneously occurring disease.
  • Signs: cerebral, eg visual deficits, circling, seizures, ataxia, and behavioral changes, eg head-pressing, continual pacing and an incoordinated high-stepping gait.
  • May or may not be history of distemper-like episode in past.
  • Diagnosis: definitive diagnosis may be difficult because of low specificity of signs.
  • Clinical picture is milder than in the acute form seen in younger animals.
  • Treatment: corticosteroids, anticonvulsants.
  • Prognosis: poor - recovery does not occur.

Pathogenesis

Etiology

  • Believed to be caused by a variant of canine distemper virus.

Predisposing factors

General
  • Presently unknown.

Specific

  • Presently unknown.

Pathophysiology

  • The underlying pathogenesis is presently unknown, however, the virus-host cell interaction appears different from that of multifocal distemper encephalitis.
  • Recent studies suggest the ODE is a variant of virulent CDV-induced canine neurological disease that can evolvede novowithin the CNS of subclinically infected dogs in absence of external sources of re-infection.
  • This is a highly cell-associated virus. Viral mutations occur after infection.
  • The virus appears to have a predilection for cerebral cortex and upper brain stem leading to progressive cortical/subcortical signs (the 'clinical signs').

Timecourse

  • This is a subacute/chronic neurologic disorder that may span many months.

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.
  • Axthelm M K & Krakourka S (1998) Experimental old dog encephalitis (ODE) in a gnotobiotic dog. Vet Pathol 35 (6), 527-534 PubMed.
  • Thomas W B (1998) Inflammatory diseases of the central nervous system in dogs. Clin Tech Small Anim Pract 13 (3), 167-168 PubMed.
  • Evans M B et al (1991) Comparison of in vitro replication and cytopathology caused by strains of canine distemper virus of vaccine and field origin. J Vet Diag Invest (2), 127-132 PubMed.
  • Rima B K et al (1987) Humoral response in dogs with old dog encephalitis and chronic distemper meningo-encephalitis. J Gen Virol 68 (Pt 6), 1723-1735 PubMed.


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