![]() 1,24,27,28 Bradycardia and reduced rumination are often observed, indicating disturbance of autonomic innervation. 24–26 The most common neurologic signs in cattle with BSE are apprehension, pelvic limb ataxia, and hyperesthesia to auditory, visual, or tactile stimuli. ![]() 22,23Ĭlinical Signs and Histopathologic Changes in Cattle With BSEĬattle with BSE develop signs of CNS disease that can be vague and nonspecific and that are often accompanied by a decrease in milk yield and loss of body weight. 20,21 Bovine spongiform encephalopathy is the only TSE known to be transmissible from animals to humans. Other well-known TSEs are scrapie of sheep, 16 transmissible mink encephalopathy, 17 chronic wasting disease of cervids, 18 and kuru 12,19 and sporadic Creutzfeldt-Jakob disease of humans. 1,4 These unusual proteins, called prions, 5 are the infectious agent of all TSEs, 6 and inoculation with these prions or sometimes merely the ingestion of tissue containing prions transmits the disease to a new host. This group of uniformly fatal diseases causes a slow-onset encephalopathy that is notable by the distinct lack of any immune response and by aggregations of characteristic protein deposits that are detectable primarily in the CNS. 2īovine spongiform encephalopathy belongs to a class of diseases known as TSEs, so named because of the vacuolization often observed in the brains of TSE-affected animals. 3 The disease has now been confirmed in native-born cattle in 25 countries throughout the world, including Asia and North America. 2 However, because the incubation period of this disease exceeds the usual slaughter age for cattle, these recorded case numbers represent only a fraction of the infected animals it has been calculated that since 1980, approximately 2 million cattle have developed BSE in the United Kingdom. 1 From its first recorded appearance in England, more than 184,500 cases have been confirmed throughout the United Kingdom, an epizootic that peaked in 1992. Bovine spongiform encephalopathy was described as a new disease of cattle in 1987.
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