Bovine spongiform encephalopathy (BSE), or mad cow disease, is an incurable neurodegenerative disease that causes the sponge-like deterioration of the spinal cord and brain of cattle. BSE caused devastating effects towards the British cattle industry between 1996 and 2006. At its climax, more than 180,000 cattle were identified as being infected and the whole eradication program resulted in 4.4 million cattle being slaughtered in the United Kingdom alone.
BSE is a prion disease meaning that it is not caused by bacteria or a virus. Rather, it is caused by the misfolding of a specific protein molecule, called prion which in turn induces structural changes in other healthy prion proteins once its own misfolding process has finished. Such misfolded prions cannot be destroyed by conventional means of cooking, and is transmissible between species. Currently, the misfolding process of disease-causing prion molecules is still considered irreversible, and very little progress has been made in the potential vaccination or treatment of such disease.
However, a recent report published in the June 10th issue of Nature suggested that a specific population of Papua New Guinea aboriginals (whom were former cannibals known for eating brains and body parts of their deceased) possess genetic variants that prevented misfolding and propagation of prion proteins. In these populations, specific amino acid substitutions – thus DNA sequence changes – have shown great resistance to the variant Creutzfeldt–Jakob disease (vCJD). Eating meat from cows infected with BSE (aka mad cow disease) results in vCJD.
Although it is still ethically disputed whether individual human genomic information can be altered, another alternative approach may provide a solution. This approach involves producing genetically engineered cattle, inspired by the resistant genes of the Papua New Guinea people, that are resistant to BSE from bovine embryonic stem cells. Once a few founder cattle carrying resistant genes are obtained, the proliferation and commercialization of such a breed (most likely patented) would be not only highly profitable, but also provide a safer food source for beef lovers.
Reference: A naturally occurring variant of the human prion protein completely prevents prion disease; Nature. 2015 Jun 10. doi: 10.1038/nature14510.
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