Disease Information for Variant Creutzfeld-Jakob disease (Mad Cow Disease)

In March of 1996, the British government announced that consumption of beef from cows with an infectious brain disorder (Bovine Spongiform Encephalopathy) may have caused a variant form of Creutzfeldt-Jakob Disease (V-CJD) in several young people in the United Kingdom; Cows with Bovine Spongiform Encephalopathy, also known as BSE or "Mad Cow Disease," experience rapidly progressive neurological and neuromuscular symptoms similar to those associated with CJD in humans; As with CJD, abnormal changes in prion proteins are also thought to play a role in the brain degeneration associated with BSE; BSE was first recognized in the UK in 1986 and was linked to contaminated cow feed composed of sheep meat and bone meal; The sheep may have been infected with scrapie; In the late 1980s, Britain banned the use of such feeds in animals raised for human consumption; Since Britain"s announcement, a global ban on British beef products was put into effect, and there has been much scientific study and debate concerning any potential link between consumption of affected beef and Variant Creutzfeldt-Jakob Disease; For example, a team of researchers from the University of California, San Francisco, US, and the National CJD Surveillance Unit, Western General Hospital, Edinburgh, UK has provided evidence suggesting that the disease-causing prion in BSE may be responsible for V-CJD; During the investigation, prion proteins were obtained from cows with BSE and from individuals with V-CJD and injected into two groups of genetically altered or "transgenic" (Tg) mice; The specific disease-causing prion proteins (isoforms), degenerative brain changes (neuropathology), and the time between initial prion exposure and symptom onset (incubation period) were indistinguishable among both groups of mice; However, when inoculation occurred with prion proteins obtained from sheep with scrapie, the results were significantly different; The study"s investigators suggest these findings may represent the first direct evidence that BSE may have been the source of the disease-causing prion proteins responsible for V-CJD in the UK; Affected Populations: By the summer of 2002, European experts had counted 97 people in Great Britain, three in France, and one in Ireland who had died or were dying from the new variant of CJD (V-CJD) since it was first identified in 1996; All of the cases identified in England had a particular genetic trait, which is not a mutation, that may have predisposed them to the condition; The genetic abnormality involves a variation of the prion protein; Approximately 40 percent of the British population has this genetic trait

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