Bovine Spongiform Encephalopathy

Also known as: BSE — Bovine Spongiform Encephalopathy, TSE — Transmissible Spongiform Encephalopathy', Mad Cow Disease, Prion — proteinaceous infectious particle, Scrapie — a transmissble prion affecting sheep that causes non-febrile neurological disease

Introduction

Bovine spongiform encephalopathy (BSE) is a prion –associated transmissible spongiform encephalopathy (TSE) which causes a non-febrile neurological disorder affecting adult cattle. It has occurred as a result of the exposure of cattle to animal and ruminant-derived protein feeds e.g. meat-and-bone meal (MBM) containing the scrapie-like agent. As the disease progresses histological changes show bilateral symmetrical vacuolation in the grey matter of the brain, gliosis and hypertrophy of astrocytes, neuronal degeneration and cerebral amyloidosis. There is no evidence to support the horizontal transmission of BSE under natural circumstances but there is evidence supporting vertical transmission ., ,

Transmissible Spongiform Encephalopathies (TSEs) are neurological diseases that have been found in humans, cattle, sheep and other mammals (e.g. cats, goats, deer, antelope). The agent of disease is believed to be an abnormal prion protein (or is prion associated). An abnormal prion is a protein with an abnormal folding structure when compared to the naturally occurring prion found in nervous and lymphoreticular tissues. Various abbreviations are in use to refer to this: Prion Protein (PrP); Abnormal Prion Protein (PrP^ab); Resistant Prion Protein (PrP^res); Scrapie Prion Protein PrP^sc) and others.

Clinical Signs

Clinical signs include progressive ataxia and pruritus.

Diagnosis

In most instances the abnormal prion is resistant to protein kinase digestion, a feature used in diagnostic techniques. Histology (immunohistochemistry) usually shows vacuolation and an accumulation of prion proteins in various parts of the CNS (especially the brain and spinal cord).