Creutzfeldt-Jakob, Mad Cow, Alzheimer’s All Deadly Prion Diseases
UK ministers might fund a renewed investigation of “hidden” mad cow disease infection in the British population. The government discussed the issue in response to a select committee report on Creutzfeldt-Jakob Disease (CJD), the human version of mad cow disease. Both are prion diseases (also known as transmissible spongiform encephalopathies–or TSEs). Prions also cause Alzheimer’s disease.
Evidence suggests that the rogue prion proteins responsible for the disease in genetically susceptible people can have a very long incubation period. In some cases individuals can carry prions for decades, or even all their lives, without developing any symptoms. These carriers, however, are contagious long before presenting symptoms of CJD.
MPs on the Science and Technology Select Committee said they feared the vCJD “storm” that caused widespread alarm in the late 1990s may only have abated and could return. In their report, they call for a large scale study of vCJD prevalence to be conducted using a new diagnostic blood test developed by Medical Research Council (MRC) scientists.
Outlining the Government’s response, public health minister Jane Ellison said: “We will explore the possibility of using the prototype test developed by the Medical Research Council Prion Unit to carry out a blood prevalence study, as the Committee recommended.”
But the Government pointed out that a number of scientific and technical hurdles had to be crossed before such a study could be undertaken. It also stressed that there were competing research funding priorities, and said starting the work within 12 months as suggested by the select committee was “ambitious.”
A total of 175 cases of vCJD were reported in the UK and 49 in other countries between October 1996 and March 2011. Thousands of cattle were destroyed, burned or buried to help contain the deadly prion disease.
The origin of the disease was supposedly traced to meat contaminated with brain and spinal cord tissue, especially cheap-cut burgers and pies consumed in the 1980s. As it turns out, the entire carcass and bodily fluids of infected animals are infectious.
Scientists discovered that variant CJD was effectively the same disease as bovine spongiform encephalopathy (BSE), which affects cattle. It is always fatal and there is no cure. CJD is closely related to Alzheimer’s disease–in fact doctors can’t tell the difference in most cases. Both diseases are part of a larger family called prion disease or transmissible spongiform encephalopathy (TSE). The only differences between the diseases may be a different mutation of the deadly prion.
Strict controls have been in place since 1996 to keep infectious prions out of the human food chain and the use of meat-and-bone mix has been outlawed.
It is also possible for vCJD to be transmitted through blood transfusions, surgeries and dental procedures and other pathways, including human sewage. Documented cases of vCJD peaked in 2000, when 28 people died from the disease in the UK. Many more cases were likely misdiagnosed as Alzheimer’s disease. The prion pathogen lurks in soil, water and other environmental pathways.