Feline spongiform encephalopathy

This paper reviews the recently recognised condition of feline spongiform encephalopathy and its importance as a neurological disorder of cats. Its possible origin and relationship to other transmissible spongiform encephalopathies are discussed.     

Bovine spongiform encephalopathy: a review

Transmissible Spongiform Encephalopathies are a group of chronic, always fatal diseases affecting the central nervous system of humans and animals. They occur in all species and are probably caused by agents called prions. In this minireview, a first part provides an overview of the various disease forms, a second part is devoted to the molecular biology of transmissible spongiform encephalopathies, and a last part deals with the specific problems of the Bovine Spongiform Encephalopathy.     

Diagnosis of bovine spongiform encephalopathy: A review

Summary

Cows affected with bovine spongiform encephalopathy (BSE) display chronic neurological signs consisting of behavioural changes, abnormalities of posture and movement, and/or hyperaesthesia. At present, there are no laboratory test available to diagnose BSE in the live animal. In this article, we describe the post‐mortem diagnostic examination of brains from BSE‐suspected cattle as currently performed at ID‐Lelystad. The routine laboratory diagnosis of BSE consists of histopathological examination of the brain and detection of the modified prion protein, PrP^BSE, in brain tissue. These tests, however, have the disadvantage of being laborious and time consuming, so that results are available only after several days.

Recently, at ID‐Lelystad a new post‐mortem test has been developed that enables screening of larger volumes of brain samples for PrP^BSE within 1 day. This BSE test is especially suited for slaughterline monitoring. A preliminary validation study has shown that both sensitivity and specificity are 100% compared to the gold diagnostic standard of histopathology.     

Diagnosis of bovine spongiform encephalopathy: a review

Cows affected with bovine spongiform encephalopathy (BSE) display chronic neurological signs consisting of behavioural changes, abnormalities of posture and movement, and/or hyperaesthesia. At present, there are no laboratory test available to diagnose BSE in the live animal. In this article, we describe the post-mortem diagnostic examination of brains from BSE-suspected cattle as currently performed at ID-Lelystad. The routine laboratory diagnosis of BSE consists of histopathological examination of the brain and detection of the modified prion protein, PrP(BSE), in brain tissue. These tests, however, have the disadvantage of being laborious and time consuming, so that results are available only after several days. Recently, at ID-Lelystad a new post-mortem test has been developed that enables screening of larger volumes of brain samples for PrP(BSE) within 1 day. This BSE test is especially suited for slaughterline monitoring. A preliminary validation study has shown that both sensitivity and specificity are 100% compared to the gold diagnostic standard of histopathology.     

Bovine spongiform encephalopathy in a cow in the United Kingdom

Bovine spongiform encephalopathy (BSE) was diagnosed in a cow with a history of behavioral change, apprehension, hyperesthesia to auditory and tactile stimuli, wide-based stance, and marked hind limb hypermetria. Myoclonus involving individual muscles was observed in the shoulder region, ventral cervical region, and upper portion of the hind limb. Clonus was observed in the forelimbs. Clinicopathologic findings were normal, except for high serum globulin concentration, which was attributable mainly to an increase in the gamma-globulin fraction. Results of electroencephalography revealed almost continuous high-amplitude complexes in the occipital leads, interspersed with short runs of normal activity. There were generalized discharges, but these were not periodic. Current theory implicates the scrapie agent (prion) as the causal agent for BSE. The presence of scrapie in, and the possible entry of prion into bovine feedstuffs could result in the emergence of BSE in the United States.     

A case of spongiform encephalopathy ("cattle madness") in a cow in Switzerland

Spongiform encephalopathies occur in humans and several domestic animal species. Among them, the bovine spongiform encephalopathy (BSE) has aroused considerable interest because of a massive outbreak of this disease in Great Britain, which is thought to result from feeding meat and bone meal contaminated with the spongiform encephalopathy agent. We observed the first case of BSE in Switzerland, which is also the first case on the European continent. A 6 year old cow suffered from progressive neurological disease. On neuropathological examination typical spongiform changes and neuronal vacuolation were found. The origin of the infection remains unknown. It cannot be excluded that the animal was exposed to cattle feed derived from Great Britain. It is possible that additional sporadic cases may occur in Switzerland, an outbreak such as in England is unlikely to happen.     

Bovine spongiform encephalopathy: epidemiological studies

This study, initiated in June 1987, describes the epidemiology of bovine spongiform encephalopathy (BSE), a recently described novel neurological disease of domestic cattle first identified in Great Britain in November 1986. Records suggested that the earliest suspected cases occurred in April 1985. There was variability in the presenting signs and the disease course, but the majority of cases developed behavioural disorders, gait ataxia, paresis and loss of bodyweight; pruritus was not a predominant sign. The form of the epidemic was typical of an extended common source in which all affected animals were index cases. The use of therapeutic or agricultural chemicals on affected farms presented no common factors. Specific genetic analyses eliminated BSE from being exclusively determined by simple mendelian inheritance. Neither was there any evidence that it was introduced into Great Britain by imported cattle or semen. The study supports previous evidence of aetiological similarities between BSE and scrapie of sheep. The findings were consistent with exposure of cattle to a scrapie-like agent, via cattle feedstuffs containing ruminant-derived protein. It is suggested that exposure began in 1981/82 and that the majority of affected animals became infected in calfhood.     

Bovine spongiform encephalopathy and human health

Because bovine spongiform encephalopathy (BSE) has probably been caused by accidental transmission of the transmissible agent of sheep scrapie there is concern that humans may be at risk from BSE. Epidemiological and experimental evidence is examined which suggests that this is unlikely.