Bovine spongiform encephalopathy

[[File:Bse-cattle-250.jpg|thumb|right|165px|Cow with BSE showing abnormal posturing and weight loss]]
{{biology}}
'''Mad cow disease''', or '''bovine spongiform encephalopathy (BSE)''', is a [[disease]] that affects cows. In [[humans]], the disease is called '''variant Creutzfeldt-Jakob Disease (vCJD)'''. The two types of BSE are "classical" BSE and "atypical BSE". Classical BSE has nearly been eradicated due to implemented control measures, and it's assumed that humans can contract classical BSE and that it causes vCJD; according to the World Organisation for Animal Health, the "hypothesis that BSE [[prion]]s have been passed to humans, causing vCJD, is strongly supported by epidemiological and clinicopathological studies." Atypical BSE is thought to be a natural, yet still very rare, condition appearing spontaneously in cattle.<ref>[https://www.woah.org/en/disease/bovine-spongiform-encephalopathy/ "Bovine spongiform encephalopathy"]. ''World Organisation for Animal Health''.</ref> As of the 2020s, atypical BSE was more common.<ref>Anand Chandrasekhar (September 16, 2023). [https://www.swissinfo.ch/eng/business/is-mad-cow-disease-making-a-comeback/48783906 "Is mad cow disease making a comeback?"]. ''SWI swissinfo'' (Swiss Broadcasting Corporation).</ref>

Though it is rare in [[human]]s, we can contract the disease through eating infected meat (but don't worry, if you die of CJD, it's much more likely you'll die of the form unrelated to cows).<ref>[https://web.archive.org/web/20150417132053/http://www.medicine.ox.ac.uk/bandolier/booth/Risk/Madcow.html Risk of death from variant Creutzfeld-Jacob Disease (vCJD) and CJD in the UK] (2007) ''Bandolier, University of Oxford'' (archived from April 17, 2015).</ref> CJD debilitates and later kills the infected person, taking between eight weeks and a couple of years, and is 100% fatal.  

The [[brain]]s and spinal cords of infected [[animal]]s are considered more infectious than other parts, and there are thus "rules against beef processors using the brains or spinal cords of the animal to make food products".<ref>[http://kidshealth.org/kid/talk/qa/mad_cow_disease.html What is Mad Cow Disease?] </ref>

Because of this, you still can't give blood in the [[USA]] if you were in the [[United Kingdom]] for more than three months total from 1980 to 1996.<ref>[https://www.redcrossblood.org/donate-blood/how-to-donate/eligibility-requirements/eligibility-criteria-alphabetical/eligibility-reference-material.html Eligibility Reference Material] ''American Red Cross''.</ref> In 2008, the disease caused a stir in [[South Korea]] when the government lifted a ban on U.S. beef imports,<ref>[https://www.reuters.com/article/us-korea-protest-idUSSEO21734120080531 Anti-U.S. beef protest draws 100,000 S.Koreans]. ''Reuters''.</ref> since Korean beef dishes tend to contain more offal than those in the US. However, part of the outrage was sparked by misinformation and pseudoscience,<ref>[http://english.chosun.com/site/data/html_dir/2008/05/09/2008050961017.html Mad Cow Thesis Twisted All Out Of Proportion]. ''chosun.com''.</ref> as well as opposition to America's economic hegemony and [[Neoliberalism]].<ref>[https://www.semanticscholar.org/paper/The-2008-Candlelight-Protest-in-South-Korea%3A-the-of-Pang/9f2022df985b483054f163706ac7f3aee0235621 The 2008 Candlelight Protest in South Korea: Articulating the Paradox of Resistance in Neoliberal Globalization]. Huikyong Pang.</ref>

The occasional [[woo]] merchant or general brain donor will come up with some mulch about BSE being an [[alien]] disease,<ref>[https://abcnews.go.com/Health/story?id=117683&page=1 Mad Cow Research: Small Steps, Big Questions] by Amanda Onion
January 6, 2006, 5:56 AM) ''ABC News''.</ref> or more specifically, alien energies.<ref>[http://www.4truthseekers.org/articles/alien_invasion_and_mad_cow_disease.php Alien invasion and mad cow disease] by Peter Farley (2006-12-12) ''4TruthSeekers.org'' (archived from July 31, 2016).</ref>

==Mechanism==
Our best theory as to the mechanism behind Mad Cow Disease, and other transmissible spongiform encephalopathies, is that it's not caused by a [[virus]] ''or'' a [[bacterium]] ''or'' a [[parasite]] ''or'' a congenital condition, but instead by a misfolded [[protein]] called a [[prion]].

Prions are fascinating [[molecule]]s. Like all protein molecules, they are chains of [[amino acids]]. In general, every protein molecule in your body does its job because of its shape; the way a given amino acid chain is "folded" in three-dimensional space determines what kinds of other molecules it can capture, latch on to, twist apart, etc. Normally, every amino acid chain will fold in one specific, predictable manner as it's being assembled from one end to the other.  However, in a few cases, the ''same'' amino acid chain can be folded into a very different shape after it's been assembled, if it's acted upon by the proper outside force. This will make the molecule incapable of performing the duty that its old shape had.

Prions (PrP<sup>Sc</sup>) are, amino-acid-for-amino-acid, identical to a nerve tissue protein called PrP<sup>C</sup>. However, they're folded in a radically different manner, which causes them to be extremely protease-resistant, almost impervious to disinfection, and one of, if not ''the'' most powerful toxin in the world. They act as catalysts to ''re-fold PrP<sup>C</sup> into new prions.''  Thus, one prion will, when introduced into neuronic tissue (such as brain tissue), create more PrP<sup>Sc</sup>.

This quasi-self-replicating behavior has led some to speculate as to whether prions should be considered a form of [[life]] (but, like viruses, prions do not respire, which is by some definitions a requirement for life).

Frustratingly, prions don't break down in the presence of acid or heat — their new structure is far more stable than PrP<sup>C</sup>. This means that neither cooking nor the digestion process can remove prions from infected cow brains.<ref>[https://www.researchgate.net/publication/7001642_Doppel_More_rival_than_double_to_prion Doppel: More rival than double to prion] by Kefeng Qin et al. (2006) ''Neuroscience'' 141(1):1-8. doi:10.1016/j.neuroscience.2006.04.057.</ref>

Cows were not the first species known to be infected by prion diseases. The [[sheep]] disease scrapie is now known to be very similar to mad cow disease. Spongiform encephalopathy first reached [[epidemic]] proportions in cows, however, due to the practice of grinding up the undesirable parts of a slaughtered cow (including the brain) and feeding this protein meal to other cows. Since the alarm bells were raised for mad cow disease, this practice has been discontinued.

==See also==
*[[Vegetarianism]]
*[[Zombies]] (No you will not become a zombie from prions)

==External links==
*{{wpl|Bovine spongiform encephalopathy|Bovine spongiform encephalopathy}} from [[Wikipedia]]
*[http://www.mad-cow.org/ The Official Mad Cow Disease Home Page]

==References==
{{reflist}}

[[Category:Disease]]
[[Category:Medicine]]

Categories: Disease, Medicine