Felis ISSN 2398-2950

Spongiform encephalopathy

Synonym(s): FSE, transmissible spongiform encephalopathy

Contributor(s): Robin Franklin, Agnes Delauche, Laurent Garosi

Introduction

  • Transmissible spongiform encephalopathy first reported in 1990.
  • Cause: infection with prion, same agent as for bovine spongiform encephalopathy (BSE).
  • Signs: behavioral changes, hypermetria, polyphagia.
  • Diagnosis: characteristic histological changes in gray matter of brain.
  • Treatment: none.
  • Prognosis: very poor.

Pathogenesis

Etiology

  • Infective agent known as prion is a small protein coding for production of membrane associated protein.
  • Same infective agent in BSE.
  • As most of the feline spongiform encephalopathy (FSE) cases occurred in parallel to the BSE epidemic, exposure of affected cats to feed contaminated with PrPBSE has been taken as causative of the disease.
  • Lesion profiles, transmission experiments in mice and western blotting studies have provided strong evidence that FSE is caused by the same agent which causes bovine spongiform encephalopathy (BSE) in cattle and new variant Creutzfeld-Jakob Disease (nvCJD) in humans.
  • However, in 1998, a domestic cat and his owner have been shown to be affected with a similar strain distinct from PrPBSE. A bifurcation in phenotypes was noted: the man revealed a phenotype reminiscent of sCJD rather than of vCJD and the cat showed a clinical phenotype disctinct from FSE. It remains unknown whether this incidence was due to a chance, whether a horizontal transmission occurred between the man and the cat, or if both contracted the disease from the same unknown source.
  • With a ban on the use as pet feed of bovine spleen and CNS tissue, the FSE epidemic declined rapidly.

Predisposing factors

General

  • The condition in cats is believed to result from ingestion of BSE contaminated food.
  • Agent present in commercial cat food prepared before ban imposed on incorporation of bovine neurological tissue in petfoods.

Pathophysiology

  • Infective agent  →  excess production of membrane associated protein  →  accumulates in brain  →  clinical signs.
  • Infection with prion  →  accumulation of abnormal form of host membrane protein (PrP).
  • Vacuolation of neuronal perikarya and neurites  →  spongiform changes in gray matter and neuronal degeneration  →  clinical signs.

Timecourse

  • Weeks to months.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Imran M, Mahnood S (2011) An overview of animal prion diseases. Virol J 8, 493 PubMed.
  • Hilbe M M, Soldati G G, Zlinszky K K et al (2009) Immunohistochemical study of PrP(Sc) distribution in neural and extraneural tissues of two cats with feline spongiform encephalopathy. BMC Vet Res 5, 11 PubMed.
  • Zanusso G, Nardelli E, Rosati A et al (1998) Simultaneous occurrence of spongiform encephalopathy in a man and his cat in Italy. Lancet 352 (9134), 116-117 PubMed.
  • No author named (1996) Feline spongiform encephalopathy - BSAVA Scientific Committee. JSAP 37 (4), 198 PubMed.
  • Bratberg B, Ueland K, Wells G A (1995) Feline spongiform encephalopathy in a cat in Norway. Vet Rec 136 (17), 444 PubMed.
  • Pearson G R, Wyatt J M, Gruffydd-Jones T J et al (1992) Feline spongiform encephalopathy: fibril and PrP studies. Vet Rec 131 (14), 307-310 PubMed.
  • Pearson G R, Gruffydd-Jones T J, Wyatt J M et al (1991) Feline spongiform encephalopathy. Vet Rec 128 (22), 532 PubMed.


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