Introduction
Bovine spongiform encephalopathy (BSE), also known as Mad Cow Disease, emerged in cattle in the UK in 1986, marking a pivotal moment in veterinary and public health history. Over a decade, the insidious disease claimed the lives of nearly 200,000 cows, prompting a rigorous scientific inquiry into its origins and potential mitigation strategies.
Amidst the investigative fervour, researchers encountered a perplexing twist: despite stringent sterilisation protocols, the instruments used in the cow autopsies inadvertently transmitted the disease to live mice involved in separate experiments. This unexpected transmission challenged conventional understanding, as pathogens such as bacteria, viruses, and parasites should not survive after procedures. So how could this disease possibly be transmitted to the mice?
Delving deeper, scientists unravelled a startling revelation: Mad Cow Disease was not caused by conventional infectious agents, but rather by prions—a misfolded form of protein. These misfolded prions possessed the ability to induce misfolding in other normal prions upon contact, perpetuating a cascade of pathological transformation similar to a domino effect. In affected cows, these proteins are found to affect the brain, spinal cord, and small intestine.
Symptoms
This infection is recognized as a degenerative disease characterised by the progressive deterioration of affected tissues or organs it causes. In this case, the misfolded prions aggregate to form fibres, which intertwine around each other, killing the neurons in the infected cow. When neurons die off, holes are left in the brain. Consequently, this results in symptoms including impaired mobility and speech, dementia, occasional hallucinations, and ultimately death.
Comparison of Cow Brains, healthy and infected, under a microscope using special stains:
Brain from a healthy cow.
Spongy Brain seen in a “mad cow”
[The large white spaces represent the holes.]
Cause of Mad Cow’s Disease
The primary cause of Mad Cow Disease was attributed to the pellets fed to cattle, specifically due to a component found within them; beef contaminated with the BSE agent. Thus, the notion arose that cows consuming their own kind might have triggered this fatal disease. While lacking definitive proof, this theory is intriguing as it appears to correlate with a variant of the disease known as Variant Creutzfeldt-Jakob disease, which affects humans similarly. As of 2019, a total of 232 individuals worldwide are documented to have fallen ill with variant Creutzfeldt-Jakob Disease, tragically resulting in fatalities for all affected individuals. Notably, this variant is prevalent in Papua New Guinea, where the practice of eating the brains of dead people as part of a funeral ritual exists rather commonly. Could this correlation serve as a cautionary tale, a warning from nature against the perils of cannibalism?
Cure
Treatment and prevention options for Mad Cow Disease are currently non-existent, as there is neither a cure nor a vaccine available. Additionally, there is currently no reliable method for testing live cows for the presence of the disease.
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