tag:theconversation.com,2011:/ca/topics/bovine-spongiform-encephalopathy-18519/articlesBovine spongiform encephalopathy – The Conversation2022-06-10T12:30:36Ztag:theconversation.com,2011:article/1817532022-06-10T12:30:36Z2022-06-10T12:30:36ZWhat is chronic wasting disease? A wildlife scientist explains the fatal prion infection killing deer and elk across North America<figure><img src="https://images.theconversation.com/files/465390/original/file-20220525-11-rwnc2s.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4486%2C3002&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Female white-tailed deer at sunrise.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/white-tailed-deer-does-moving-at-sunrise-royalty-free-image/695666692">Gary Gray/Getty Images</a></span></figcaption></figure><p><em><a href="https://pubs.usgs.gov/of/2017/1138/ofr20171138.pdf">Chronic wasting disease</a>, a deadly neurological infectious disease that affects deer, elk and moose, is spreading across North America. Most recently detected in North Carolina in March 2022, CWD has been confirmed in 30 U.S. states and <a href="https://inspection.canada.ca/animal-health/terrestrial-animals/diseases/reportable/cwd/what-hunters-should-know/eng/1601393370403/1601393370841">four Canadian provinces</a>, as well as <a href="https://www.cdc.gov/prions/cwd/occurrence.html">Norway, Finland, Sweden and South Korea</a>. <a href="https://www.researchgate.net/profile/Allan-Houston-2">Dr. Allan Houston</a>, a professor of forest and wildlife ecology at the University of Tennessee’s 18,400-acre <a href="https://ames.tennessee.edu/">Ames AgResearch and Education Center</a> in western Tennessee, explains what is known about CWD and what wildlife scientists are trying to learn.</em></p>
<h2>How does chronic wasting disease affect animals?</h2>
<p>Chronic wasting disease is contagious and relentless. There is no cure, no way to test living animals, and once infections are introduced into wild populations, there is no realistic way to stop them from spreading. </p>
<p>An infected deer typically will survive for 18 months to two years. There’s a long incubation period in which they don’t usually show symptoms, but as the disease progresses, the animals will <a href="https://pubs.usgs.gov/of/2017/1138/ofr20171138.pdf">begin to appear listless and lose weight</a>. </p>
<p>In the final six weeks or so they can seem aimless and oblivious to danger, become emaciated and drool. They often stand with their legs spread like sawhorses, as if trying not to topple over. </p>
<p>These so-called “zombie deer” <a href="https://abcnews.go.com/Health/zombie-deer-disease-spreading-us/story?id=61107970">often get media attention</a>, but as the disease progresses in the wild, deer become more susceptible to other diseases, less able to protect themselves, more prone to predation and more apt to be <a href="http://dx.doi.org/10.7589/0090-3558-41.3.503">hit by cars</a>. They rarely live long enough to become zombies.</p>
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<a href="https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing where CWD has been detected in North America." src="https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=308&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=308&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=308&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=387&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=387&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464107/original/file-20220518-25-eibjnl.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=387&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chronic wasting disease has established itself in 30 states and four Canadian provinces.</span>
<span class="attribution"><a class="source" href="https://www.usgs.gov/media/images/distribution-chronic-wasting-disease-north-america-0">United States Geological Survey</a></span>
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<h2>How long have scientists known about CWD?</h2>
<p>Chronic wasting disease was first detected in the mid-1960s when penned deer in Colorado began to exhibit symptoms generally described as “wasting away.” Researchers attributed it to stress until the late 1970s, when wildlife veterinarian <a href="https://doi.org/10.1354%2Fvp.42-5-529">Beth Williams</a> performed necropsies on deer that had died of a similar syndrome. She found brain lesions consistent with <a href="https://doi.org/10.1021/ar050068p">transmissible spongiform encephalopathies</a> – diseases of the nervous system that afflict both animals and humans.</p>
<p>In 1978, Williams and neuropathologist Stuart Young co-wrote the first scientific paper that <a href="http://dx.doi.org/10.7589/0090-3558-16.1.89">described chronic wasting disease as a TSE</a>. But the underlying cause remained a mystery.</p>
<p>A year later, neurologist <a href="https://www.nobelprize.org/prizes/medicine/1997/prusiner/facts/">Dr. Stanley Prusiner</a> was studying TSE diseases and discovered that a very small protein could become misshapen and resistant to the body’s ability to take it apart. It entered cells, tricking them into replicating it, then moved into the lymph and nervous systems. Eventually it moved to the brain, where small clumps aggregated and caused TSE. Prusiner called that nonliving, infectious protein <a href="http://dx.doi.org/10.1073/pnas.95.23.13363">a “prion</a>.” </p>
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<a href="https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/465601/original/file-20220526-18-88qlor.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The natural social behaviors of deers help spread chronic wasting disease.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/deer-licking-fawn-on-snow-covered-field-royalty-free-image/1145795534?adppopup=true">Tamas Zsebok/Getty Images</a></span>
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<h2>Does CWD threaten humans?</h2>
<p>Prion diseases <a href="https://www.cdc.gov/prions/index.html">are always fatal</a>, but they don’t all affect the same species. The CWD prion <a href="https://doi.org/10.4161/pri.2.4.7951">favors cervids, or deerlike animals</a>. Other prions cause human illnesses such as <a href="https://www.cdc.gov/prions/cjd/index.html">Creutzfeld-Jakob disease</a>, a malady that progresses similarly to accelerated Alzheimer’s.</p>
<p><a href="https://www.cdc.gov/prions/bse/index.html">Bovine spongiform encephalopathy</a>, popularly known as “mad cow disease,” is a prion disease that infects cattle. In a small number of cases, humans exposed to BSE have <a href="https://www.cdc.gov/prions/bse/bse-north-america.html">developed a version of Creutzfeld-Jakob disease</a>.</p>
<p>No human case of CWD has ever been recorded. However, several laboratory experiments have shown that the CWD prion could be <a href="https://pubs.usgs.gov/of/2017/1138/ofr20171138.pdf">transferred to other mammals</a>. The <a href="https://www.cdc.gov/prions/cwd/index.html">Centers for Disease Control and Prevention</a> warns against eating meat from infected animals. Some infectious disease experts contend that “while the CWD threat to humans is <a href="https://doi.org/10.1128/mBio.01091-19">low, it is not zero</a>” and that risk assessments must include the potential for the emergence of new strains.</p>
<p>For example, while no one knows how or where CWD originated, some scholars think a mutated prion jumped the species barrier to deer from sheep infected with another animal prion disease called <a href="https://www.aphis.usda.gov/aphis/ourfocus/animalhealth/nvap/NVAP-Reference-Guide/Control-and-Eradication/Scrapie">scrapie</a>.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/N0Y5IHRbtqU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Animals with chronic wasting disease don’t typically show symptoms in the early stages of infection.</span></figcaption>
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<h2>Why are prion diseases so hard to combat?</h2>
<p>Because of their structure and the fact that they don’t contain genetic material, prions like the one that causes CWD are <a href="https://blogs.scientificamerican.com/artful-amoeba/prions-are-forever/">nearly indestructible</a>. Breaking a prion apart, or denaturing it, would require a very high concentration of chlorine solution or heat exceeding 1,800 degrees F (980 C). </p>
<p>Once they are deposited on the landscape in urine or feces, <a href="http://dx.doi.org/10.4161/pri.2.4.7951">CWD prions can persist for decades</a>. Years after deer infected with chronic wasting disease were removed from pens, other deer placed on the contaminated soil in those same pens also became infected.</p>
<p>In wild herds the prion is spread as deer, which are highly social animals, groom and lick one another. During the fall mating season, bucks search for mates, fight and breed. They also visit spots known as scrapes, where they lick the soil and overhead branches where other deer have left their own calling cards. Thanks to these behaviors, bucks usually have CWD at double the rate of does. </p>
<p>Because the disease does not kill quickly, infected animals are able to breed for a season or two, so there is no strong genetic selection pressure favoring the development of herdwide immunity. And recent research suggests infected does can occasionally <a href="http://dx.doi.org/10.1371/journal.pone.0071844">transmit the prion to their fawns before birth</a>.</p>
<p>In some places where CWD occurs, the infection rate may only be 1% to 5%, and the disease’s herdwide impact may not be apparent, even to hunters. Elsewhere, the infection rate can reach 50% and maybe even 100%. In those cases, population impacts will inevitably lead to a smaller and younger herd. </p>
<h2>What do hunters need to know?</h2>
<p>No one wants a disease named after them. With infected deer often appearing healthy, even at close range post-harvest, the only way to be sure an animal is disease-free is to have it tested, usually using lymph nodes.</p>
<p>As CWD spreads and more people are having deer tested, it can take weeks to receive the results. That makes meat processing a much more onerous affair.</p>
<p>It is critical to recognize that once a single deer is infected it acts like tinder to ignite a conflagration. Moving deer around, either alive or dead, can introduce and spread the disease. </p>
<p>For example, <a href="https://texasfarmbureau.org/cwd-discovered-at-two-texas-deer-breeding-facilities/;%20https://www.outdoorlife.com/conservation/cwd-outbreak-wisconsin-deer-farm/">transferring deer between breeding farms</a> has been associated with its introduction. Disregarding state wildlife regulations that explain the proper ways to transport and dispose of harvested deer, elk or moose <a href="https://www.cdc.gov/prions/cwd/prevention.html">can also spread CWD</a>. <a href="https://newschannel9.com/sports/outdoors/cwd-brings-new-variable-to-deer-baiting-debate">Feeding and baiting stations and salt licks</a> can increase infection rates by concentrating deer and creating a point-source buildup of prions. </p>
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<h2>What do you want to learn about CWD?</h2>
<p>CWD was detected in northern Mississippi and western Tennessee, where I work, in 2019. Based on what was then a relatively high infection rate, it had likely been on the landscape for a number of years and was spreading rapidly. Currently, about 40% of the Ames research station’s herd is infected. </p>
<p>Research on CWD has been ongoing for decades <a href="https://cwd-info.org">around the country</a>. But it is in the South now. At Ames, in cooperation with other scientists from around the country, we are analyzing soil and twig samples for prion concentrations and quantifying deer visits at scrape sites and salt stations. We are also investigating ways to destroy salt stations to avoid continued exposure. </p>
<p>Other studies include training dogs to detect metabolites associated with the disease, and developing an early warning system before the prion can metastasize across a landscape.</p>
<p>We are studying how hunters react when CWD is detected locally, and comparing hunting success before and after a herd has become infected. The perspectives of hunters are important because they love the outdoors and are the first stopgap in CWD’s spread. Hunting is the primary tool for deer management, especially control of overabundant deer populations <a href="https://pubs.usgs.gov/of/2017/1138/ofr20171138.pdf">where CWD can run rampant</a>. </p>
<p>Our deer hunters participate in the research at every step and often collect samples from deer they harvest. As one hunter said, “We’ve brought in everything except the tracks.” </p>
<p>We hope we can scale up our efforts along with other scientists as we analyze an ailing herd to provide insights into chronic wasting disease for the benefit of animals and humans alike.</p><img src="https://counter.theconversation.com/content/181753/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Research on chronic wasting disease at the Ames station is conducted in cooperation with the University of Tennessee, Mississippi State University, the University of Wisconsin and Colorado State University. </span></em></p>A deadly neurological infection, chronic wasting disease, has been detected in deer, elk and moose in 30 states and four Canadian provinces. Human risk is low, but hunters need to take precautions.Allan Houston, Professor of Forest and Wildlife Ecology, University of TennesseeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1250592019-11-19T20:13:59Z2019-11-19T20:13:59ZIn science, it’s better to be curious than correct<figure><img src="https://images.theconversation.com/files/302538/original/file-20191119-111645-1tke0aw.jpg?ixlib=rb-1.1.0&rect=7%2C15%2C5104%2C2858&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Scientists can make mistakes, but it's important to keep an open mind and curious approach when conducting research.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>I’m a geneticist. I study the connection between information and biology — essentially what makes a fly a fly and a human a human. <a href="https://droso4schools.wordpress.com">Interestingly, we’re not that different</a>. I’ve been a professional geneticist since the early 1990s. I’m reasonably good at this, and <a href="https://doi.org/10.1534/g3.117.043836">my research group has</a> <a href="https://dx.doi.org/10.1534%2Fgenetics.111.133231">done some really good work</a> <a href="https://doi.org/10.1534/g3.114.012484">over the years</a>. </p>
<p>But one of the challenges of the job is coming to grips with the idea that much of what we think we <em>know</em> is in fact wrong. Sometimes, we’re just off a little and we try to get a little closer to the answer. At some point, though, it’s likely that we’re just flat out wrong in some aspect. </p>
<p>We can’t know when we’re wrong, but it’s important to remain open-minded and adaptable so we can learn from our mistakes. Especially because sometimes the stakes can be incredibly high with lives on the line (more on this later). </p>
<h2>Infected tissues</h2>
<p>In the late 1980s, cattle started wasting away. In the late stages of what was slowly recognized as a disease, <a href="https://www.cnn.com/2013/07/02/health/mad-cow-disease-fast-facts/index.html">cattle began acting in such bizarre manner</a> that their condition — bovine spongiform encephalopathy — became known as mad cow disease. Strikingly, the brains of the cattle were full of holes (hence spongiform) that were caked with plaques of proteins clumped together; these were proteins that were found in the brains of healthy cattle, but now they had an unnatural shape. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&rect=48%2C0%2C6442%2C2647&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=246&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=246&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=246&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=309&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=309&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302523/original/file-20191119-111630-14ems4p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=309&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Most of the scientists working to explain mad cow disease made assumptions about its cause.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Proteins are long chains, but they fold into specific complex shapes. But the proteins in the cattles’ brains were misfolded. Some time after, people started dying from the same symptoms, and a connection was made between eating infected cattle and contracting the disease. Researchers determined that the culprit was consumption of brain and spinal tissue, the only tissue that showed the physical effects of infection. </p>
<p>One of the challenges to explaining mad cow disease was the length of time from infection to disease to death. Diseases, we knew, were transmitted by viruses and bacteria, but no scientist could isolate one that would explain this disease. Further, no one knew of other viruses or bacteria whose infection would take this long to lead to death. Science leaned toward assuming a viral cause, and <a href="https://doi.org/10.1111/j.1365-2559.1992.tb00909.x">careers and reputations were built on finding the slow virus</a>.</p>
<h2>Misfolded proteins</h2>
<p>In the late 1980s, a pair of British researchers suggested that <a href="https://doi.org/10.1038/214764a0">perhaps the misfolded proteins in the plaques was key</a>. This proposal was soon championed by Stanley Prusiner, a young American researcher early in his career. The idea was simple: the misfolded protein was both the result and cause of the infection. </p>
<p>The misfolded protein plaques killed brain tissue and caused correctly folded versions of the proteins to misfold. Prusiner’s hypothesis was straightforward, but it didn’t fit the way scientists understood diseases to work. Diseases are transmitted as DNA (and in rare cases, RNA) by viruses or bacteria. But they are not transmitted in protein folding.</p>
<p>For holding this protein-based view of infection, Prusiner was <a href="https://www.theguardian.com/science/2014/may/25/stanley-prusiner-neurologist-nobel-doesnt-wipe-scepticism-away">literally and metaphorically shouted out of the room</a>. Then he showed, experimentally and elegantly, that the misfolded proteins, which he called prions, were the cause of these diseases. For this accomplishment, he was awarded <a href="https://www.nobelprize.org/prizes/medicine/1997/summary/">the 1997 Nobel Prize in medicine</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/299550/original/file-20191030-17893-kz6hlv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">An artist’s rendering of a folded protein chain.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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</figure>
<p>We now know that prions are responsible for a series of diseases in humans and other animals, <a href="https://www.ofah.org/issues/cwd/">including chronic wasting disease, a disease whose spread poses a serious threat to deer and elk in Ontario</a>.</p>
<p>Some believe that over-cooking prion-infected meat will cause prions to lose their unnatural shape and therefore be safe to eat. That’s not true. And wildlife like elk and deer get prion-based diseases too, which means hunters need to be vigilant with their game and never consume meat from animals that could be infected. In North America, <a href="https://mbio.asm.org/content/10/4/e01091-19">as many as 15,000 infected animals may be consumed each year, posing an incredible health risk</a>. The <a href="http://www.cidrap.umn.edu/cwd">Center for Infectious Disease Research and Policy at the University of Minnesota</a> has valuable information on chronic wasting diseases in the wild.</p>
<p>So in this case, the information necessary for disease transmission is the shape of the protein, not in the genetic code of an infecting virus or bacteria. This fact is why this case specifically speaks to me as a geneticist. All my career, I’ve been trained to look for answers in DNA sequences. Prions remind me that sometimes really interesting answers are not where we expect them to be.</p>
<h2>The price of denial</h2>
<p>Where does this leave us? To me, the take-home message is that we need to remain skeptical but curious. Examine the world around us with open eyes and be ready to challenge and question our assumptions. Also, we shouldn’t ignore what is in front of us simply because it doesn’t fit our understanding of the world around us. </p>
<p>Climate change, for example, is real. It’s another example of why it’s important to be open to being wrong and the need to try to get it right. Medical science only started controlling mad cow disease after we understood the role of prions, and the years of denial cost an untold number of lives. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302292/original/file-20191118-66921-4wazy0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Taking action on climate change means recognizing our role in causing it.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>Similarly, our global refusal to accept the massive climate change around us, and our obvious role in it, <a href="https://www.theguardian.com/environment/ng-interactive/2018/dec/21/deadly-weather-the-human-cost-of-2018s-climate-disasters-visual-guide">is leading us into one weather-based disaster after another, and all the loss of life associated with these disasters</a>.</p>
<p>I’ve spent a lot of time in my career putting together models of how the biological world works, but I know that pieces of these models are wrong. I can almost guarantee you that I have something as fundamentally wrong as those prion-deniers, I just don’t know what it is. Yet.</p>
<p>But the important thing isn’t to be right. Instead, it is to be open to seeing when you are wrong.</p>
<p><em>This is a corrected version of a story originally published Nov. 19, 2019. The earlier story wrongly stated that heating prion-infected meat sufficiently causes prions to lose their unnatural shape, making the meat safe to eat.</em></p><img src="https://counter.theconversation.com/content/125059/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Merritt receives funding from Natural Sciences and Engineering Research Council of Canada and the Canada Research Chairs Program.</span></em></p>Mistakes can be made during scientific research with devastating effects. Keeping an open mind to the possibility of error and correcting immediately can make the difference between life and death.Thomas Merritt, Professor and Canada Research Chair, Chemistry and Biochemistry, Laurentian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/918142018-02-23T11:43:15Z2018-02-23T11:43:15ZMad cows, Oprah Winfrey and communicating the science in a high-profile court case<figure><img src="https://images.theconversation.com/files/207638/original/file-20180223-108122-1hjhvna.jpg?ixlib=rb-1.1.0&rect=2%2C96%2C1782%2C1212&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A reporter interviews a protester outside the Amarillo courthouse.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Associated-Press-Domestic-News-Texas-United-Sta-/f096abe143e5da11af9f0014c2589dfb/3/0">AP Photo/Eric Gay</a></span></figcaption></figure><p>Twenty years ago, images of staggering cattle and descriptions of brains resembling Swiss cheese became associated with one of the most popular television programs of the day when <a href="http://caselaw.findlaw.com/us-5th-circuit/1177368.html">Texas Panhandle cattlemen sued</a> “The Oprah Winfrey Show” for defamation under Texas’ “<a href="http://www.statutes.legis.state.tx.us/Docs/CP/htm/CP.96.htm">veggie libel law</a>.” They claimed the program’s negative portrayal of their business caused a steep decline of beef prices. </p>
<p>On the surface, this conflict looked like a battle between an industry and the TV producers who portrayed it negatively. But at its heart was some complicated science that had the potential to scare the public and be sensationalized by the media. </p>
<p>Today’s practitioners of science communication grapple with the difficulty of <a href="https://global.oup.com/academic/product/the-oxford-handbook-of-the-science-of-science-communication-9780190497620">transmitting science information via the media</a> to a lay audience. This 1998 trial serves as a rare public case study documenting the media’s imperfect attempts to clarify the <a href="https://www.fda.gov/AnimalVeterinary/ResourcesforYou/AnimalHealthLiteracy/ucm136222.htm">science of mad cow disease</a> in the midst of a celebrity spectacle.</p>
<p>Ultimately Oprah won the legal case. But how did the public’s understanding of the science fare? </p>
<h2>Facts of the case</h2>
<p>A year and a half earlier, rancher-turned-animal-rights activist Howard Lyman appeared on Winfrey’s program. He claimed the American beef industry was giving cattle feed that contained remains of processed cattle. This practice, <a href="https://www.fda.gov/AnimalVeterinary/GuidanceComplianceEnforcement/ComplianceEnforcement/BovineSpongiformEncephalopathy/default.htm">no longer legal in the U.S.</a>, had been <a href="http://webarchive.nationalarchives.gov.uk/20100514231604/http://www.food.gov.uk/scotland/regsscotland/regulations/scotlandfoodlawguide/sflgpart06/sflgpart06branch02/sflgpart06branch02doc03">banned by the British government in 1996</a> due to the belief it had led to the <a href="https://www.cbsnews.com/news/chronology-of-mad-cow-crisis/">1980s outbreak in Great Britain</a> of bovine spongiform encephalopathy.</p>
<p>BSE is a fatal nervous system disease in cattle; a human form of the disease, Creutzfeldt-Jakob, was subsequently diagnosed in England, causing the <a href="https://www.cjd.ed.ac.uk/sites/default/files/figs.pdf">deaths of 178 people in the U.K.</a> through 2017. Medical researchers believed this form of CJD was caused by eating the meat of cattle infected with BSE.</p>
<p>Upon hearing these revelations Winfrey proclaimed on-air, “<a href="http://www.nytimes.com/1998/01/21/us/talk-of-the-town-burgers-v-oprah.html">It has just stopped me cold from eating another burger!</a>” The “<a href="https://www.usatoday.com/story/life/tv/2015/10/19/oprah-effect-does-everything-she-touches-turn-gold/74211636/">Oprah effect</a>” kicked into gear and the term “mad cow disease” rose in the public consciousness.</p>
<p>The resulting lawsuit initially focused on the science of BSE and the extent of the danger to beef consumers. However, the judge’s ruling ultimately hinged on legal questions of freedom of speech, rather than whether “The Oprah Winfrey Show” broadcast scientifically valid findings. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/206919/original/file-20180219-75997-1y9dfwl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Was American beef dangerous for consumers?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/dongkwan/2411796681">Ernesto Andrade</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Science from lawyers, via media, to public</h2>
<p>The verdict itself doesn’t provide a clear reflection of how effectively the science of BSE had been communicated during the trial to the jury. But the case was also tried, as they say, in the court of public opinion.</p>
<p>U.S. District Judge Mary Lou Robinson imposed a gag order on the attorneys, prohibiting them from talking about the case outside of court. She did, however, provide permanent seats in the Amarillo courtroom for local media. One of us (Larry Lemmons) was the lead reporter for the local CBS affiliate during the trial.</p>
<p>Celebrity sightings around the courthouse were common. PETA protesters traded insults with local restaurant employees grilling burgers for the crowd. Presumably because I was one of the primary local media reporters, my reports were followed by attorneys from both sides. When I personally met Oprah Winfrey she remarked, “So you’re Larry Lemmons.” I never figured out precisely what that meant.</p>
<p>My media colleagues and I struggled to understand and communicate the specifics of BSE. We listened to the attorneys present the science to the jury, and then communicated those details to the public, who tended to be more interested in the spectacle.</p>
<p>In Amarillo in 1998, although access to the internet was growing more common, we reporters tended to regard it with suspicion. We gathered news the old-fashioned way, via in-person or phone interviews. For BSE research, I went to the library and a local college where a science professor provided me with some background. Part of my job as a reporter was to get the complicated scientific facts straight, and I couldn’t ask any of the trial participants for clarification.</p>
<p>Looking back over two decades, I wondered if my challenges communicating the science were shared by colleagues and other important players in the trial. Now, as a doctoral student of media and communication (working with Dr. Landrum and others at Texas Tech), I contacted some of them to discuss how attorneys related the science of BSE to the jury and how the media subsequently reported on information presented in the courtroom.</p>
<h2>Thinking back to the trial</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=536&fit=crop&dpr=1 600w, https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=536&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=536&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=673&fit=crop&dpr=1 754w, https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=673&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/207642/original/file-20180223-108125-98vlya.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=673&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Oprah celebrates the ruling in her favor on Feb. 26. 1998.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Associated-Press-Domestic-News-Texas-United-Sta-/4122616744e5da11af9f0014c2589dfb/5/0">AP Photo/LM Otero</a></span>
</figcaption>
</figure>
<p>As expected, there are conflicting perspectives on how effectively the science was communicated.</p>
<p>Howard Lyman’s defense attorney, Barry Peterson, said that “to prevail I had to inform the jury that there was reasonable scientific evidence to support Howard’s opinions.” But he also had to consider the political environment: “We were more concerned about our ability to successfully defend Howard and HARPO Production because we are in beef country.”</p>
<p>Despite representing the losing side, one of the plaintiff’s attorneys Vince Nowak said the trial was a success for the cattle industry because it convinced the public that BSE was not a serious threat to American livestock. Though he presented extensively on the science during the trial, he acknowledged that “science played a very small factor” in the subsequent ruling by the judge.</p>
<p>Nevertheless, some reporters said the local cattle industry, who were not affected by the judge’s gag order, should have been more eager to clarify to the media the relative risks of Texas cattle becoming infected with BSE. At the time, Kay Ledbetter worked for the Amarillo Globe-News. She said obtaining scientific information was frustrating and limited to what was discussed in the courtroom:</p>
<blockquote>
<p>“There was nobody reliable to discuss what the disease – bovine spongiform encephalopathy – really was … We were left with the catch phrase Mad Cow Disease, and our imagination.”</p>
</blockquote>
<p>On the other hand, Stacy Yates, who covered the trial for local news radio station KGNC, thought both the defense and plaintiffs did a reasonable job communicating the science and that “if you were a person who wanted to understand the science, the coverage was there.”</p>
<p>Ultimately the media covering this trial were left to muddle through as best we could – and the public relied on our efforts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/207640/original/file-20180223-108125-1dwihoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The case hinged on controversial feeding practices.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Food-and-Farm-Beef-Prices/514ac11bd9fc4c5791f8c098c26fa21b/4/0">AP Photo/Nati Harnik, File</a></span>
</figcaption>
</figure>
<h2>The name matters</h2>
<p>My own notes from the trial are rich with legal and scientific explanations that accompanied courtroom observations. Notes for one report included this passage:</p>
<p>“[Winfrey’s] attorney Charles Babcock tried to establish links between what’s called ‘new variant CJD’ in humans and mad cow disease in cattle. [Primary plaintiff Paul] Engler insisted upon precise scientific answers while Babcock tried to put the issue in layman’s terms.” </p>
<p>However, recent research on how to most effectively communicate science has found that sometimes <a href="https://global.oup.com/academic/product/the-oxford-handbook-of-the-science-of-science-communication-9780190497620">putting a scientific issue into less accurate layman’s terms</a> can add to confusion and heighten controversy.</p>
<p>Ledbetter is now an agriculture science communicator for Texas A&M AgriLife, a statewide agricultural research institution. She said that by using the term “mad cow disease,” the media misrepresented the issue:</p>
<blockquote>
<p>“It’s not Mad Cow Disease, it’s bovine spongiform encephalopathy or BSE. And if agriculture would have taken the same stance on this issue as they did on Swine Flu, trying to educate on what it really was and asking the media to call it by its real name, H1N1, many people wouldn’t have had the same concerns.”</p>
</blockquote>
<p>Ledbetter’s point of view is supported by science communication research. In one study, researchers investigating a subsequent mad cow outbreak in France determined that the framing of the issue influences public perception. When people were confronted with the term “mad cow,” they <a href="https://doi.org/10.1111/j.0956-7976.2005.00811.x">reacted more emotionally</a> than they did to a scientific label, such as BSE. It’s an open question, though, how opinion would have changed with the use of a more deliberative description of the disease during the Oprah Winfrey lawsuit. </p>
<p>Today the CDC considers the risks to Americans from BSE to be “<a href="https://www.cdc.gov/prions/bse/bse-north-america.html">extremely low</a>.” Since 1993 there have been a total of only 25 cases of BSE in North American cattle, the majority of those in Canada. In “A Comparative Study of Communication About Food Safety Before, During, and After the ‘Mad Cow’ Crisis,” food law scholar Matteo Ferrari concluded the public decides <a href="https://doi.org/10.1093/oxfordhb/9780190497620.013.15">whom to trust regarding the message</a> by how government, industry or advocates frame it.</p>
<p>In this case, the jury determined the media’s First Amendment protections outweighed the defamation concerns presented by the plaintiffs. Ironically, because of the media focus on the trial, the perspectives of the cattle industry were also highlighted.</p>
<p>The public got the message that there was little evidence that BSE threatened American livestock in a substantial way. Two decades of hindsight suggest that lawyers and media – in perhaps a piecemeal, stumbling way – did transmit relatively accurate science information. The cattlemen may have lost the case, but U.S. media consumers were left with the understanding that U.S. beef was safe. Media professionals still struggle with knowing how to best explain and condense complex science and public health issues in ways that won’t inappropriately trigger defensiveness, denial or fear. Research in the area of the science of science communication has made great strides in exploring these issues, but there is still much work to be done.</p><img src="https://counter.theconversation.com/content/91814/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Twenty years ago, a Texas court decided Winfrey hadn’t defamed the state’s cattle industry. At the time, local media struggled to explain the science at stake in the case.Larry Lemmons, Doctoral Student in Communications, Texas Tech UniversityAsheley R. Landrum, Assistant Professor of Media and Communication, Texas Tech UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/469362015-09-07T20:07:59Z2015-09-07T20:07:59ZNew prion disease raises questions about whether Alzheimer’s and Parkinson’s could be infectious<figure><img src="https://images.theconversation.com/files/94009/original/image-20150907-29002-11sib7y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Prion diseases are a rare class of brain disorders that are transmissible between animals of any species, including humans.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/thedjneight/4047040029/">djneight/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p><a href="http://www.pnas.org/content/early/2015/08/27/1514475112.full.pdf">Research published last week</a> has identified the first new human prion disease in 50 years. The paper’s lead author, <a href="https://en.wikipedia.org/wiki/Stanley_B._Prusiner">Stanley Prusiner</a>, who won the Nobel prize in 1997 for his discovery that <a href="https://theconversation.com/rare-and-deadly-creutzfeldt-jakob-disease-remains-a-bit-of-a-medical-mystery-44408">Creutzfeldt-Jakob disease (CJD)</a> could be transmitted by a “misfolded” protein, says this new disease is also potentially infectious.</p>
<p>Prion diseases are a rare class of brain disorders that are transmissible between animals of any species, including humans. The <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581658/">archetypal such disease is kuru</a>, which spread through cannibalistic rituals in the Eastern Highlands of Papua New Guinea. </p>
<h2>Rare and deadly</h2>
<p>Kuru affected mostly women and children of the Fore tribe, who ate brains and spinal cords of deceased relatives, and subsequently developed body tremors, balance problems and slurred speech. There’s no cure for kuru and sufferers always died. But it no longer strikes as cannibalism in the region has been eliminated. </p>
<p>Other prion diseases include <a href="https://en.wikipedia.org/wiki/Scrapie">scrapie in sheep and goats</a> and <a href="https://en.wikipedia.org/wiki/Bovine_spongiform_encephalopathy">bovine spongiform encephalopathy</a> (BSE) in cows. When transmitted to humans during the “mad cow disease” outbreak in Europe, BSE resulted in variant CJD (vCJD). </p>
<p>The newly described addition to the prion disease canon, Shy-Drager syndrome (SDS) or multiple system atrophy (MSA), was <a href="http://archneur.jamanetwork.com/article.aspx?articleid=562589">first recognised in the early 1960s</a> and has many features in common with Parkinson’s disease. </p>
<p>The most important of these is that a protein known as α-synuclein (α-syn) accumulates in the brain, in both Parkinson’s and SDS/MSA. This accumulation is very similar to what happens in CJD, where the prion protein (PrP) accumulates, and also in Alzheimer’s disease and other dementias, where two types of proteins, known as amyloid beta (Aβ-amyloid) and tau, build up in the brain. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=476&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=476&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=476&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=599&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=599&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94007/original/image-20150907-28970-t6awd3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=599&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The word prion comes from an amalgam of _pro_teinaceous _in_fectious particle.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ajc1/973805461/">AJ Cann/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
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</figure>
<p>The clumps and tangles of these various aggregated proteins cause neurons to degenerate and die. This is a cumulative process which takes between months and decades to manifest as overt disease. </p>
<p>In fact, many of the neurodegenerative diseases of the ageing brain are associated with the accumulation and deposition of specific proteins. It has <a href="http://onlinelibrary.wiley.com/doi/10.1002/ana.22615/abstract">long been suspected</a> that neurodegenerative diseases in general may all ultimately be caused by this process of proteins getting caught in the wrong process, and misfolding.</p>
<p>This misfolding sets off a cascade of events: the proteins oligomerise (a number of identical molecules join together); accumulate; nucleate (form a nucleus or centre); polymerise (combine to build a structure with its components); self-replicate; and eventually, propagate and spread throughout the brain. Many of these protein changes also occur in the usual food cooking process (aggregation of proteins caused by heating) or food preparation (the solidification of proteins in the refrigerator).</p>
<p>Finally, some but not all of these misfolded proteins gain the ability to be transmitted between people and animals. In fact, the word “prion” was <a href="http://www.ncbi.nlm.nih.gov/pubmed/6801762">coined by Prusiner in 1982 to describe this property</a> of a _pro_teinaceous _in_fectious particle. And we don’t yet know of ways to easily “dis-infect” or kill these proteins. All kinds of chemicals that kill bacteria and viruses do not harm prions.</p>
<h2>Infectious proteins</h2>
<p>Scientists have always kept – and still do – an open mind about whether Alzheimer’s disease and other neurodegenerative conditions are transmissible. <a href="http://www.ncbi.nlm.nih.gov/pubmed/12011456">We’ve known since the early 1960s</a> that amyloid fibrils – the accumulations of Aβ-amyloid in the brain - are self-propagating entities. </p>
<p>In diseases involving amyloid protein, the “amyloid enhancing factor”, which causes the disease to progress, is thought to be amyloid itself. In other words, the amyloid is self-replicating and makes copies of itself exponentially.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94008/original/image-20150907-28970-1u89fq0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Scientists have always kept an open mind about whether Alzheimer’s disease and other neurodegenerative conditions are transmissible.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/isaacmao/544903/">Isaac Mao/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We know that the Alzheimer’s disease-causing human Aβ-amyloid can cross-seed Aβ-amyloid accumulation in genetically susceptible rodents. Mice carrying an unstable and genetically modified human protein can then be “infected” by giving them a dose of the human abnormal protein. <a href="http://www.neurology.org/content/30/9/945">But there’s still no direct evidence</a> that Alzheimer’s disease is transmissible between people. </p>
<p>Working out whether SDS/MSA is transmissible, at least from humans to genetically susceptible transgenic cell and rodents, is the first step in testing if it’s transmissible from humans to primates, or indeed among people. </p>
<p>As a precautionary measure, the authors of the paper warn we should now take additional safety precautions in the neurosurgical clinics where <a href="http://www.nejm.org/doi/full/10.1056/nejmoa060281">deep brain stimulation is used to control the tremors</a> caused by Parkinson’s disease. Because of the overlap in symptoms and signs of Parkinson’s with SDS/MSA, it’s likely that some people with the newly described disease have been treated by deep brain stimulation. </p>
<p>It’s important to ensure that cross-contamination of neurosurgical equipment doesn’t occur because we don’t want to inadvertently transmit a disease between humans. Using disposable stimulation electrodes, for instance, will be mandatory in the future. <a href="http://www.jbc.org/content/early/2014/05/23/jbc.R114.549295">Similar concerns have already been raised</a> about other neurodegenerative illnesses, such as diseases involving misfolded tau protein, which cause frontotemporal dementia.</p>
<p>With the <a href="http://www.pnas.org/content/early/2015/08/27/1514475112.full.pdf">publication of this paper</a>, the spectrum of prion diseases has been enlarged, perhaps considerably. But until it becomes possible to evaluate the role of intra-species transmission, SDS/MSA will have to remain in the category of “hypothetically transmissible to a genetically susceptible recipient”. </p>
<p>It’s premature to classify it as being the same as CJD, which is clearly transmissible within and between species. That has been made apparent by the mad cow saga, which still has years to run due to the long latency from prion infection to overt disease.</p><img src="https://counter.theconversation.com/content/46936/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Colin Masters does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>New research has identified a known neurodegenerative disease as being caused by prions. And it has again raised the possibility that these proteins are infectious.Colin Masters, Distinguished Florey Fellow, Florey Institute of Neuroscience and Mental HealthLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/444082015-07-08T20:06:44Z2015-07-08T20:06:44ZRare and deadly, Creutzfeldt-Jakob disease remains a bit of a medical mystery<figure><img src="https://images.theconversation.com/files/87741/original/image-20150708-31560-16q3575.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Creutzfeld-Jacob disease occurs in about one to two in every million people each year, most often in late middle-age.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/a_mason/4006709/">Andrew Mason/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Creutzfeld-Jacob disease (CJD) is a rare degenerative disease of the brain that causes rapidly progressive loss of memory and muscle control followed by death, usually within 12 months of onset. In developed countries such as Australia, <a href="http://www.cjd.ed.ac.uk">it occurs</a> in about one to two in every million people each year, most often in late middle-age.</p>
<p>The <a href="http://www.abc.net.au/news/2015-07-07/frank-burton-diagnosed-with-creutzfeldt-jakob-disease-in-sydney/6602544">recent report</a> that Frank Burton – a former financial officer of the Sydney Swans – has contracted CJD and only has a short time to live, is a real tragedy for the man and his family. </p>
<p>But the reporting of such a celebrity case only serves to highlight that we still don’t know how to prevent a disease that most often goes unreported in the media, and unremarked on, except by family and friends.</p>
<h2>Two Nobel prizes later</h2>
<p>Inevitably, media about CJD has been intermittent, reflecting changes in attention and our understanding over the years. </p>
<p>By the 1960s, scientists had recognised that the microscopic changes in the brain of CJD patients were spongiform, that is, they resembled the porous structure of a sponge. And they knew this was similar to what happened in the brain of people <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581658/">dying from kuru</a>, a disease that had become an epidemic among the isolated Fore people in Papua New Guinea. </p>
<p>Kuru was known to almost certainly result from the cannibalism of diseased individuals. It was shown to be transmissible to chimpanzees following injection of kuru brain, and CJD was also subsequently shown to be transmissible. </p>
<p>Carleton Gajdusek, the American physician and medical researcher who <a href="http://www.nobelprize.org/nobel_prizes/medicine/laureates/1997/prusiner-bio.html">won the 1976 Nobel Prize</a> for leading that work, initially thought that CJD and kuru were caused by related viruses. But no such virus could be identified in the brains of CJD or kuru patients. And it eventually became clear that the capacity to transmit disease to animals depended on a changed structural protein in diseased tissue. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=412&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=412&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=412&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=518&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=518&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87740/original/image-20150708-31583-1qa9gqi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=518&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A Papua New Guinean tribe - though not this one - suffered a ‘kuru’ epidemic, which was linked to cannibalism.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Picturesque_New_Guinea_Plate_XXXIX_-_Group_and_Native_House,_Mairy_Pass.jpg">John William Lindt/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This transmissible protein was named a “prion” by the American neurologist and biochemist <a href="https://en.wikipedia.org/wiki/Stanley_B._Prusiner">Stan Prusiner</a>. He also developed the concept that, over time, a small amount of an abnormal (injected) prion could create more of itself by changing the shape of the normal prion in brain, leading to the onset of “prion diseases” such as CJD or kuru. </p>
<p>The prion concept was well supported by animal experiments, leading to a <a href="http://ind.ucsf.edu/ind/aboutus/faculty/prusiners">Nobel Prize for Prusiner</a> in 1997. </p>
<p>By the 1980s, there had been alarming reports of CJD being inadvertently transmitted to human patients by grafts of dura mater, the tough outer membrane enveloping the brain and spinal cord. And by hormones prepared from deceased people who were presumably incubating CJD, whose tissues must have been contaminated by abnormal prions. </p>
<p>Medical authorities moved to eliminate the risk by banning such grafts, and by sourcing hormones prepared using recombinant DNA rather than hormones prepared from human tissues.</p>
<p>But the 1980s delivered another shock when mad-cow disease (BSE or bovine spongiform encephalopathy) erupted in the cattle population of the United Kingdom and other countries. The outbreak was traced to the practice of using meat and bone meal, prepared from slaughtered cattle, as a feeding supplement for calves. </p>
<p>It was soon realised that this practice (effectively <a href="http://www.fda.gov/AnimalVeterinary/ResourcesforYou/AnimalHealthLiteracy/ucm136222.htm">bovine cannibalism</a>) was amplifying the proportion of altered prion in successive generations of cattle, and driving the BSE outbreak.</p>
<p>Soon after action was taken to control the outbreak, there were concerns about whether the inadvertent consumption of BSE-affected tissues by the British public would result in transmission of prion disease to humans. Sure enough, in 1995, the first cases of variant CJD – a version of the illness that results from BSE exposure – were diagnosed, affecting people at a much younger age than the more usual (sporadic) form of CJD. </p>
<p>By 2013, when the outbreak of variant CJD seemed over, there had been 177 cases recognised in United Kingdom, with smaller numbers in other, less affected countries. Over the same time period, there had been some 2,000 cases of <a href="http://www.cjd.ed.ac.uk/">sporadic CJD in the United Kingdom</a>.</p>
<h2>Reducing risk</h2>
<p>Medical authorities have acted to reduce the possibility of human-to-human transmission of CJD by introducing more stringent procedures for cleaning and sterilising surgical instruments that might inadvertently transmit traces of prion from person to person. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=504&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=504&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87730/original/image-20150708-31572-18bcqby.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=504&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">People who ate meat contaminated with mad-cow disease developed ‘variant CJD’.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/121483302@N02/14013976368/in/photolist-5irBoZ-e6bxVS-nmnhWd-r4tc8L-amfAiK-89uGPg-7YtQjh-wvPGo-xsnAt-8DSqkk-dRaBzx-7JuMTZ-34ayXy-5AxN8K-u2G854-6VESwi-98USB8-u2TWWG-7N5zHY-28PfE-9Fpxqy-8E3y5Y-2VqGc-8FMohx-2U36r-9rK5sd-3n8sj-5btvat-5pnr6R-5jU1V9-pzijGv-2qaNWY-52q7qw-6S4T75-6MY5G-mCfjJ-PkaN4-7xc8PW-8hQteB-dTY26A-5fXMAk-6tY2Uo-6FzpYP-7wHfv2-JTzXd-GCtAc">Global Panorama/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Restrictions on blood transfusion were also introduced to reduce the possibility that blood donors might have been exposed to BSE-affected material. But that was not before three people in the United Kingdom had developed variant CJD after <a href="http://www.ncbi.nlm.nih.gov/pubmed/24916465">exposure to a blood transfusion</a> from a person who later developed the disease. </p>
<p>Although the epidemic of variant CJD now seems to be over, there are unanswered questions about the number of people in the United Kingdom who were exposed to BSE, and who might still be at risk of disease, or of transmitting it to others. </p>
<p>Australia is fortunate in that we didn’t have outbreaks of BSE or variant CJD. And if the world attends to feeding practices in cattle and other species, it’s unlikely there will be any future outbreaks of transmissible versions of prion disease in animals or people.</p>
<p>Still, the origin of sporadic CJD, the most usual transmissible form of the disease in humans, remains something of a puzzle. Early Australian work indicated that sporadic CJD risk was slightly greater in people with a history of surgery. This is consistent with the idea that a seeding dose of altered prion might have been <a href="http://www.ncbi.nlm.nih.gov/pubmed/10073510">transmitted by surgery</a> or transfusion many years previously. </p>
<p>Subsequent work suggests sporadic CJD risk may be <a href="http://www.ncbi.nlm.nih.gov/pubmed/25279832">most increased</a> in people exposed to surgery as children. There’s continuing uncertainty about this, but we should be reassured on two grounds: first that sporadic CJD is still very rare, so that the absolute risk is still only one to two for every million people. And second that the necessary steps have already been taken to reduce the possibility of any further transmission by way of surgery or blood transfusion. </p>
<p>We can trust these preventive measures will serve us well into the future. Meanwhile as research proceeds, we should come to better understand why abnormal prions are more likely to cause disease when exposure happens at younger ages. </p>
<p>One possibility is that older people are often protected from abnormal prions by an immune response, which is less effective in younger people. Such understanding could open up new ways of preventing prion diseases.</p>
<p><em><strong>Correction:</strong> This article previously said “Blood donations are now routinely tested to exclude any contaminated with altered prions.” This is incorrect and the sentence has been removed.</em></p><img src="https://counter.theconversation.com/content/44408/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Mathews does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>News that a Sydney man has contracted Creutzfeld-Jacob disease serves to highlight that we still don’t know how to prevent a disease that most often goes unreported, and unremarked on.John Mathews, Honorary Professorial Fellow, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.