If you Google “mad cow disease” you will find a plethora of crazy cartoonish cows and terrible tongue-in-cheek humour. However mad cow disease, or bovine spongiform encephalopathy (BSE) is no joking matter, especially considering that the majority of Ionic Magazine readers (yes, you) might have been exposed to the infectious agent. BSE belongs to a group of fatal neurodegenerative disorders called prion diseases, made infamous following the outbreak of BSE and its subsequent transmission to humans as variant Creutzveldt-Jakob disease (vCJD) in the 1990s. This type of prion disease presents clinically with dementia, hallucinations, and finally blindness with the inability to speak or move. These devastating symptoms are largely due to the death of neurons and the typical sponge-like vacuoles that appear in the brains of those affected. And, as mentioned earlier, death is certain.
Although the UK has suffered the highest number of vCJD deaths, the effect was global with cases arising as far as USA, Canada and Japan. At the height of the BSE epidemic in 1992, 900,000 contaminated carcasses are believed to have passed through the food chain that year alone. So ask yourself ‘how many burgers can a single infected cow produce, and how many McDonald’s did I eat in 1992’?
In 2011, 59 Britons were notified of being “at risk” of contracting CJD after undergoing surgery with the same surgical instruments that were previously used on two patients later found to be carrying the genetic form of CJD. Indeed there is a need to drastically improve disinfection techniques, as infectious prions cannot be destroyed easily.
To date, just 176 UK individuals have died of vCJD; clearly there is a large discrepancy between predicted exposure and clinical disease. But why? In fact prion diseases have a remarkably long incubation period. Kuru, a prion disease that arose among the Fore People of Papua New Guinea, due to the consumption of deceased relatives, has variable incubation periods, which often exceed 50 years. Individuals silently incubating vCJD pose a risk to the general public through blood donations for example. Professor John Collinge, one of the world’s leading experts in prion diseases, is famed for suggesting that 1 in 1000 Britons is currently incubating vCJD. If this estimate stands firm the future of Britain’s people is bleak; a second wave could kill as many as 60,000 of us. Fortunately such estimates rarely stand the test of time. But what’s being done, just in case mad cow disease is a ticking time-bomb?
Currently immunotherapy is the forerunner of prion therapeutics. In 2003, prion-attacking antibodies were shown to cure mice with peripheral prion infection. However, if the infection was allowed to reach the brain before treatment was started, the mice were not cured. This is because the antibodies could not cross the blood-brain barrier and were prevented from entering the brain due to their large size. However in 2010 a new and much smaller prion-attacking antibody was extracted from the blood of camels and successfully entered the brain. Only time will tell if these antibodies may be effective in curing prion disease both peripherally and centrally. Until then, Keep Calm, and Carry on waiting.
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