tag:theconversation.com,2011:/us/topics/herpes-6298/articlesHerpes – The Conversation2022-01-24T13:31:35Ztag:theconversation.com,2011:article/1707722022-01-24T13:31:35Z2022-01-24T13:31:35ZHow mRNA and DNA vaccines could soon treat cancers, HIV, autoimmune disorders and genetic diseases<figure><img src="https://images.theconversation.com/files/441838/original/file-20220120-9603-u5kjhi.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3840%2C2160&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Nucleic acid vaccines use mRNA to give cells instructions on how to produce a desired protein.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/messenger-rna-or-mrna-strand-3d-rendering-royalty-free-image/1295693748?adppopup=true">Libre de Droit/iStock via Getty Images</a></span></figcaption></figure><p><em>The two most successful coronavirus vaccines developed in the U.S. – the Pfizer and Moderna vaccines – are both mRNA vaccines. The idea of using genetic material to produce an immune response has opened up a world of research and potential medical uses far out of reach of traditional vaccines. <a href="https://scholar.google.com/citations?user=eNprtJEAAAAJ&hl=en&oi=ao">Deborah Fuller is a microbiologist</a> at the University of Washington who has been studying genetic vaccines for more than 20 years. We spoke to her about the <a href="https://theconversation.com/mrna-vaccines-asteroid-missions-and-collaborative-robots-what-to-watch-in-science-in-2022-podcast-174413">future of mRNA vaccines for The Conversation Weekly podcast</a>.</em> </p>
<p><em>Below are excerpts from that conversation which have been edited for length and clarity.</em> </p>
<h2>How long have gene-based vaccines been in development?</h2>
<p>This type of vaccine has been in the works for <a href="https://doi.org/10.1038/356152a0">about 30 years</a>. Nucleic acid vaccines are based on the idea that DNA makes RNA and then RNA makes proteins. For any given protein, once we know the genetic sequence or code, we can design an mRNA or DNA molecule that prompts a person’s cells to start making it. </p>
<p>When we first thought about this idea of putting a genetic code into somebody’s cells, we were studying both DNA and RNA. The mRNA vaccines did not work very well at first. They <a href="https://www.nature.com/articles/nrd.2017.243">were unstable</a> and they caused pretty strong immune responses that were <a href="https://doi.org/10.1038/nrd.2017.243">not necessarily desirable</a>. For a very long time DNA vaccines took the front seat, and the very <a href="https://dx.doi.org/10.1038%2Fnrg2432">first clinical trials were with a DNA vaccine</a>.</p>
<p>But about seven or eight years ago, mRNA vaccines started to take the lead. Researchers solved a lot of the problems – notably the <a href="https://doi.org/10.1038/mt.2008.200">instability</a> – and discovered <a href="https://doi.org/10.1073/pnas.1209367109">new technologies to deliver mRNA</a> into cells and ways of modifying the coding sequence to <a href="https://doi.org/10.1038/nrd.2017.243">make the vaccines a lot more safe to use in humans</a>.</p>
<p>Once those problems were solved, the technology was really poised to become a revolutionary tool for medicine. This was just when COVID-19 hit. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A scanning electron microscope image of blue lumpy sphere of a T cell." src="https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441840/original/file-20220120-8772-9mk8e5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">DNA and mRNA vaccines are much better at producing T cells than are normal vaccines.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/niaid/5950870236/in/photolist-2mEvEdt-a4RLoY-2mEn5zV-bo51Vz-MSuhWU-bo5rrZ-2kLN4tU-2kLN4uF-SjQFf7-2ewYf1r-rx2LVN-su1wdR-2j4icVg-2iKmbjG-2mfURRa-a7RGBX-xvJ8TV-2hVm2XZ-2hVhUoD-2iKjyJj-51svu9-51ojDi-51sByA-ni2rkv-2iKgNob-Fwbp7g-EpF3rg-HKERqY-51sBff-51ojop-2mfSkUp-2mfMhmB-2mfLV8V-2mfQZZp-2mfLTAG-2mfVWsD-2mfRRSs-2mfQJMF-2mfUQ1m-2mfSjPU">NIAID/NIH via Flickr</a></span>
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<h2>What makes nucleic acid vaccines different from traditional vaccines?</h2>
<p>Most vaccines induce antibody responses. Antibodies are the primary immune mechanism that blocks infections. As we began to study nucleic acid vaccines, we discovered that because these vaccines are expressed within our cells, they were also <a href="https://www.gavi.org/vaccineswork/what-are-nucleic-acid-vaccines-and-how-could-they-be-used-against-covid-19#:%7E:text=Nucleic%20acid%20vaccines%20use%20genetic,immune%20response%20against%20it">very effective at inducing a T cell response</a>. This discovery really prompted additional thinking about how researchers could use nucleic acid vaccines not just for infectious diseases, but also for immunotherapy to treat cancers and chronic infectious diseases – like HIV, hepatitis B and herpes – as well as autoimmune disorders and even for gene therapy.</p>
<h2>How can a vaccine treat cancers or chronic infectious diseases?</h2>
<p>T cell responses are very important for identifying cells infected with chronic diseases and aberrant cancer cells. They also play a big role in eliminating these cells from the body.</p>
<p>When a cell becomes cancerous, it <a href="https://www.cancer.gov/publications/dictionaries/cancer-terms/def/neoantigen">starts producing neoantigens</a>. In normal cases, the immune system detects these neoantigens, recognizes that something’s wrong with the cell and eliminates it. The reason some people get tumors is that their immune system isn’t quite capable of eliminating the tumor cells, so the cells propagate.</p>
<p>With an mRNA or DNA vaccine, the goal is to make your body better able to recognize the very specific neoantigens the cancer cell has produced. If your immune system can recognize and see those better, it will <a href="https://doi.org/10.1038/d41586-019-03072-8">attack the cancer cells and eliminate them from the body</a>. </p>
<p>This same strategy can be applied to the <a href="https://www.genengnews.com/insights/immunotherapy-targets-emerging-infectious-diseases/">elimination of chronic infections</a> like HIV, hepatitis B and herpes. These viruses infect the human body and stay in the body forever unless the immune system eliminates them. Similar to the way nucleic acid vaccines can train the immune system to eliminate cancer cells, they can be used to train our immune cells to recognize and eliminate chronically infected cells. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A syringe inserted into a vaccine vial." src="https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441842/original/file-20220120-9349-1yi871k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">There are dozens of ongoing trials testing the efficacy of mRNA or DNA vaccines to treat cancers or chronic diseases.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/syringe-and-coronavirus-vaccine-royalty-free-image/1287271384?adppopup=true">Stefan Cristian Cioata/Moment via Getty Images</a></span>
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<h2>What is the status of these vaccines?</h2>
<p>Some of the very first clinical trials of nucleic acid vaccines happened in the 1990s and <a href="https://doi.org/10.1073/pnas.90.23.11307">were for cancer</a>, particularly for <a href="https://doi.org/10.1038/nrg2432">melanoma</a>.</p>
<p>Today, there are a <a href="https://www.cancernetwork.com/view/messenger-rna-vaccines-beckoning-of-a-new-era-in-cancer-immunotherapy">number of ongoing mRNA clinical trials</a> for the treatment of melanoma, prostate cancer, ovarian cancer, breast cancer, leukemia, glioblastoma and others, and there have been some promising outcomes. Moderna recently announced promising results with its phase 1 trial using mRNA to <a href="https://www.businesswire.com/news/home/20211112005897/en/Moderna-Announces-Presentation-of-Interim-Data-from-Phase-1-Study-of-mRNA-Triplet-Program-at-2021-SITC-Annual-Meeting">treat solid tumors and lymphoma</a></p>
<p>There are also a lot of ongoing trials looking at cancer DNA vaccines, because DNA vaccines are <a href="https://doi.org/10.1186/s13046-019-1154-7">particularly effective in inducing T cell responses</a>. A company called Inovio recently demonstrated a significant impact on cervical cancer caused by human papilloma virus in women <a href="https://ir.inovio.com/news-releases/news-releases-details/2021/INOVIO-Highlights-Key-Updates-on-Phase-3-Program-for-VGX-3100-its-DNA-based-Immunotherapy-for-the-Treatment-of-Cervical-HSIL-Caused-by-HPV-16-andor-HPV-18/default.aspx">using a DNA vaccine</a>.</p>
<h2>Can nucleic acid vaccines treat autoimmune disorders?</h2>
<p>Autoimmune disorders occur when a person’s immune cells are actually attacking a part of the person’s own body. An example of this is multiple sclerosis. If you have multiple sclerosis, your <a href="https://www.mayoclinic.org/diseases-conditions/multiple-sclerosis/symptoms-causes/syc-20350269">own immune cells are attacking myelin</a>, a protein that coats the nerve cells in your muscles.</p>
<p>The way to eliminate an autoimmune disorder is to modulate your immune cells to prevent them from attacking your own proteins. In contrast to vaccines, whose goal is to stimulate the immune system to better recognize something, treatment for autoimmune diseases seeks to dampen the immune system so that it stops attacking something it shouldn’t. Recently, researchers created an mRNA vaccine encoding a myelin protein with slightly tweaked genetic instructions to prevent it from stimulating immune responses. Instead of activating normal T cells that increase immune responses, the vaccine caused the body to <a href="https://doi.org/10.1126/science.aay3638">produce T regulatory cells</a> that specifically suppressed only the T cells that were attacking myelin.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A diagram showing DNA turning into mRNA which turns into proteins." src="https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=618&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=618&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=618&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=776&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=776&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441841/original/file-20220120-8832-1sa98ad.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=776&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Many diseases result when people have mutations or are missing certain genes, and nucleic acid vaccines could act as temporary replacements for the missing genes.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/mrna-and-protein-synthesis-difference-royalty-free-illustration/1323350905?adppopup=true">ttsz/iStock via Getty Images</a></span>
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<h2>Any other applications of the new vaccine technology?</h2>
<p>The last application is actually one of the very first things that researchers thought about using DNA and mRNA vaccines for: gene therapy. Some people are born missing certain genes. The goal with gene therapy is to supply cells with the missing instructions they need to produce an important protein. </p>
<p>[<em>Over 140,000 readers rely on The Conversation’s newsletters to understand the world.</em> <a href="https://memberservices.theconversation.com/newsletters/?source=inline-140ksignup">Sign up today</a>.]</p>
<p>A great example of this is cystic fibrosis, a genetic disease caused by mutations in a single gene. Using DNA or an mRNA vaccine, researchers are investigating the feasibility of essentially replacing the missing gene and allowing someone’s body to <a href="https://www.cff.org/gene-therapy-cystic-fibrosis#rna-therapy">transiently produce the missing protein</a>. Once the protein is present, the symptoms could disappear, at least temporarily. The mRNA would not persist very long in the human body, nor would it integrate into people’s genomes or change the genome in any way. So additional doses would be needed as the effect wore off.</p>
<p>Research has shown that this concept is feasible, but it still needs some work.</p><img src="https://counter.theconversation.com/content/170772/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Deborah Fuller is co-founder of Orlance, Inc, a biotechnology company developing a needle free technology to deliver RNA and DNA vaccines. She also serves as a scientific advisor for HDT Bio, a biotechnology company developing RNA vaccines for COVID19 and other infectious diseases; scientific advisor for Abacus, Inc., a biotechnology company developing cancer vaccines and scientific advisor for SQZ Biotech, a biotechnology company developing cell-based therapies for cancer and infectious diseases. She is also serving as a vaccine expert for Wilmerhale on legal matters. She receives funding supporting basic and translational research in RNA and DNA vaccines from the National Institutes of Health.</span></em></p>DNA and mRNA vaccines produce a different kind of immune response than traditional vaccines, allowing researchers to tackle some previously unsolvable problems in medicine.Deborah Fuller, Professor of Microbiology, School of Medicine, University of WashingtonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1686362021-11-10T13:40:52Z2021-11-10T13:40:52ZThe chickenpox virus has a fascinating evolutionary history that continues to affect peoples’ health today<figure><img src="https://images.theconversation.com/files/429786/original/file-20211102-19-1gjsqqg.jpg?ixlib=rb-1.1.0&rect=57%2C0%2C5406%2C3489&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Most children today receive the chickenpox vaccine as a routine part of childhood immunizations. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/chickenpox-royalty-free-image/1144939011?adppopup=true">Solidcolours/E+ via Getty Images</a></span></figcaption></figure><p>In July 2021, a Centers for Disease Control and Prevention presentation <a href="https://www.washingtonpost.com/context/cdc-breakthrough-infections/94390e3a-5e45-44a5-ac40-2744e4e25f2e/">obtained by the press</a> noted that the delta variant of COVID-19 “is as transmissible as chickenpox.” </p>
<p>As some researchers have pointed out, <a href="https://www.npr.org/sections/goatsandsoda/2021/08/11/1026190062/covid-delta-variant-transmission-cdc-chickenpox">the CDC’s comparison was an overstatement</a>. Based on various studies and projections, on average a person infected with the delta strain of COVID-19 can infect six or seven people, whereas someone infected with chickenpox can infect nine or 10. Nonetheless, both diseases are highly contagious, although the viruses that cause them are very different.</p>
<p>While many diseases, such as <a href="https://www.cdc.gov/vhf/ebola/about.html">Ebola</a> and <a href="https://theconversation.com/influenzas-wild-origins-in-the-animals-around-us-91058">influenza</a>, originate from viruses that made relatively recent “jumps” from animals to humans, other disease-causing pathogens have been with humans throughout evolution. The virus that causes chickenpox is one of these, coexisting with the human evolutionary line for <a href="https://doi.org/10.1128/JVI.00357-12">millions of years</a>. </p>
<p>I am a microbiologist interested in <a href="https://biology.indiana.edu/about/faculty/foster-patricia.html">pathogens and the diseases they cause</a>. Chickenpox is a childhood disease, and until a couple of decades ago, nearly <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/chickenpox">all children in the United States got it</a>. A vaccine campaign that began in the 1990s has made the disease rare in children in the U.S., but the virus lingers in the body and can reappear in unvaccinated adults years later as shingles. The virus’s ability to do this disappearing-and-reappearing trick may be the key to its <a href="https://doi.org/10.1128/JVI.00357-12">long evolutionary history</a>.</p>
<h2>Chickenpox and shingles stem from the same virus</h2>
<p>I became painfully aware of the virus that causes chickenpox a few years ago when my husband developed shingles soon after starting a stressful job. <a href="https://doi.org/10.1111/bjd.19832">Chronic stress is one trigger</a> for reactivation of the dormant virus, as it is for the closely related <a href="https://doi.org/10.3389/fmicb.2019.00016">herpes viruses</a>.</p>
<p>The virus that causes both chickenpox and shingles, varicella-zoster, is only known to <a href="https://doi.org/10.1038/nrdp.2015.16">infect humans</a>. “Varicella” means “<a href="https://www.merriam-webster.com/dictionary/varicella">little variola</a>,” or little smallpox, because both diseases cause skin blisters.</p>
<figure class="align-center ">
<img alt="Varicella zoster (chickenpox) virus, illustration." src="https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=540&fit=crop&dpr=1 754w, https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=540&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/427906/original/file-20211021-22-18g4m4p.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=540&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Varicella-zoster, the virus depicted in this illustration, causes both chickenpox in children and shingles in adults.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/varicella-zoster-viruses-illustration-royalty-free-illustration/1209159885?adppopup=true">Roger Harris/Science Photo Library/Science Photo Library via Getty Images</a></span>
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<p>Shingles is known in medical terms as herpes zoster. Both “zoster” and “shingles” derive from words for belt or girdle in <a href="https://www.merriam-webster.com/dictionary/zoster">Greek</a> and <a href="https://www.merriam-webster.com/dictionary/shingles">Latin</a>, respectively, referring to the typical arrangement of blisters on the torso during shingles outbreaks. </p>
<h2>Chickenpox is primarily a childhood disease</h2>
<p>Chickenpox is spread by inhalation, and children are infectious a few days before <a href="https://www.cdc.gov/chickenpox/about/transmission.html">symptoms appear</a>. The blisters also contain live viruses that can become <a href="https://doi.org/10.1038/nrdp.2015.16">airborne and inhaled</a> or can be transmitted through direct contact. After inhalation, chickenpox viruses invade the cells of the respiratory tract, replicate in the lymph nodes and are spread by white blood cells throughout the body. Eventually, they <a href="https://www.cdc.gov/vaccines/pubs/pinkbook/varicella.html">lodge in the skin</a>, causing the itchy blisters that are characteristic of the disease.</p>
<p>In healthy children, chickenpox lasts about a week and goes away without medical intervention. But it can be more severe in adolescents, adults and people with compromised immune systems. Infection with chickenpox typically provides <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/chickenpox">lifelong immunity to reinfection</a>.</p>
<h2>Shingles mostly affects older adults</h2>
<p>Even after the chickenpox blisters are gone, the varicella-zoster virus is not. The viruses travel to nerve root clusters <a href="https://www.cdc.gov/vaccines/pubs/pinkbook/herpes-zoster.html">located along the spinal cord</a>. There, the viruses establish a persistent, dormant state in the <a href="https://doi.org/10.1038/nrdp.2015.16">nuclei of the nerve cells</a>.</p>
<p>Over the course of a person’s life, the viruses may reactivate, but usually the immune system eliminates the active viruses before they can appear as shingles. However, as the immune system weakens with age, or as a result of illness or stress, reactivated viruses can travel back along the nerves and erupt again as painful blisters. Typically, only one nerve-root cluster is involved, and the blisters appear in the area of the skin supplied by those nerves. This leads to the classic <a href="https://www.cdc.gov/vaccines/pubs/pinkbook/herpes-zoster.html">belt-like appearance</a>, although the blisters can localize to other areas of the skin.</p>
<p>Although even children can develop shingles, the risk of that happening and the severity of the disease increases sharply after the age of 50. The CDC estimates that 1 in 3 people in the U.S. <a href="https://www.cdc.gov/shingles/surveillance.html">will have shingles</a> at some point in their lives. In healthy adults, a shingles outbreak typically lasts from seven to 10 days; however, about 15% of shingles sufferers develop persistent, often debilitating, neurological pain, called <a href="https://doi.org/10.1038/nrdp.2015.16">postherpetic neuralgia</a>, that can last for months or even years. </p>
<h2>Varicella-zoster has a long, slow evolutionary history</h2>
<p>Unlike the COVID-19 and influenza viruses, which have genomes of <a href="https://asm.org/Articles/2020/July/COVID-19-and-the-Flu">single-stranded RNA</a>, varicella-zoster’s genome is double-stranded DNA. This makes its genome more stable and able to be copied more accurately than <a href="https://doi.org/10.1128/JVI.00694-10">single-stranded RNA genomes</a>. </p>
<p>Although experts disagree on the exact rate at which varicella-zoster accumulates genetic changes, called mutations, a reasonable estimate of its evolution rate is one new mutation every <a href="https://doi.org/10.1099/0022-1317-75-3-513">200</a> to <a href="https://doi.org/10.1371/journal.pone.0022527">400</a> years. This rate is in contrast to influenza, for example, whose RNA genome is copied so sloppily that it accumulates about 40 new mutations every year, according to my calculations based on <a href="https://doi.org/10.1128/JVI.02163-13">data published here</a>. </p>
<p>Varicella-zoster is a member of a large group of viruses, the Herpesviridae, that <a href="https://doi.org/10.1007/s00705-008-0278-4">infect mammals, birds and reptiles</a>. Although there have been some “<a href="https://doi.org/10.1093/ve/veab025">jumps” between hosts in the distant past</a>, these viruses tend to infect only specific hosts. Thus, scientists can deduce the evolutionary history of the viruses by looking at the known <a href="https://doi.org/10.1006/jmbi.1995.0152">evolutionary relationships of their hosts</a>. </p>
<p>Such analyses indicate that the viruses that eventually led to varicella-zoster and its relatives existed 200 million years ago in the <a href="https://doi.org/10.1093/ve/veab025">Triassic/Jurassic period</a> – the age of dinosaurs! The closest existing relative to varicella-zoster infects an <a href="https://doi.org/10.1006/viro.2001.0912">old-world monkey</a>. The evolutionary lines that led to humans and old-world monkeys split <a href="https://doi.org/10.1093/molbev/msg050">23 million years ago</a>; thus, our cohabitation with varicella-zoster goes back at least that far.</p>
<p>Recent DNA analysis of varicella-zoster strains currently infecting humans complicates this history somewhat. The data indicates that the virus is accumulating <a href="https://doi.org/10.1093/infdis/jiz227">mutations faster</a> than would be consistent with its evolutionary history, and that the ancestor of the current strains appeared only <a href="https://doi.org/10.1093/molbev/msu406">about 8,000 years ago</a>. Such discrepancies between short-term and long-term evolutionary rates have appeared in <a href="https://doi.org/10.1016/j.cub.2021.08.020">numerous similar studies</a>, and scientists are <a href="https://doi.org/10.1146/annurev-ecolsys-011921-023644">currently analyzing why this is so</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of Shingles vaccine with syringe in background." src="https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/429783/original/file-20211102-39236-xwqges.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 CDC recommends that all adults age 50 and older get vaccinated for shingles.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/shingles-vaccine-syringe-stock-photo-royalty-free-image/1264660305?adppopup=true">Fotolgahan/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>The ability to enter a latent state may have given varicella-zoster a survival advantage. Ancient hunter-gatherers would have lived in small groups where an outbreak of chickenpox could have infected the whole population. <a href="https://doi.org/10.1128/JVI.00357-12">A credible theory</a> proposed by Charles Grose, a pediatric infectious disease specialist at the University of Iowa, holds that, since chickenpox conveys lifelong immunity, the survivors could not be reinfected. And without new hosts, the virus would die out. However, by persisting for years in survivors in its latent state, varicella-zoster could reappear after a new generation of children was born. Since the shingles blisters are infectious, these children would get chickenpox and a new cycle would begin.</p>
<h2>Vaccines for chickenpox and shingles are effective</h2>
<p>Prior to 1995, when the chickenpox vaccine was introduced, nearly all U.S. children got infected with <a href="https://doi.org/10.1038/nrdp.2015.16">chickenpox by age 10</a>. Although usually mild, rare complications resulted in more than <a href="https://www.cdc.gov/chickenpox/vaccine-infographic.html">10,000 hospitalizations and 100 deaths per year</a>. </p>
<p>The two-dose vaccine has resulted in greater than 90% protection against infection. Currently the vaccination rate among schoolchildren <a href="https://www.cdc.gov/mmwr/volumes/70/wr/mm7003a2.htm">approaches 95%</a>. By preventing the virus from spreading, this level of vaccination <a href="https://www.cdc.gov/vaccines/pubs/pinkbook/varicella.html">protects unvaccinated children</a> through <a href="https://theconversation.com/what-is-herd-immunity-a-public-health-expert-and-a-medical-laboratory-scientist-explain-170520">herd immunity</a>. </p>
<p>The chickenpox vaccine is a live, attenuated varicella-zoster strain that, like the original strain, stays in the body in a dormant state. But the vaccine strain is <a href="https://doi.org/10.1542/peds.2018-2917">weakened for activation</a>, and as of 2016 <a href="https://doi.org/10.1093/cid/ciy954">data show</a> that children vaccinated for chickenpox develop shingles less frequently than children did when chickenpox was common. Public health experts do not yet know whether the rate of vaccine-derived shingles will rise as the vaccinated population ages and becomes more susceptible to the disease.</p>
<p>Shingrix, an effective, protein-based vaccine against shingles, has been available since 2017. The CDC recommends <a href="https://www.cdc.gov/shingles/multimedia/shringrix-50-older.html">everyone over age 50 to get vaccinated</a> for shingles, whether or not they have had chickenpox, shingles or have been vaccinated with Zostavax – a former shingles vaccine that was less effective. Shingrix reduces the incidence of shingles an average of 97% and, if a case occurs, reduces the <a href="https://www.cdc.gov/vaccines/vpd/shingles/public/shingrix/index.html#how-well-does-shingrix-work">incidence of postherpetic neuralgia by 91%</a>.</p>
<p>Vaccination requires two doses and is known, so far, to be protective for <a href="https://doi.org/10.1093/infdis/jiab387">at least 10 years</a>. As of 2018, <a href="https://www.cdc.gov/nchs/products/databriefs/db370.htm?deliveryName=USCDC_171-DM32740">34.5% of U.S. adults 60 and over</a> were vaccinated against shingles, most with Zostavax.</p>
<p>With effective vaccines against both chickenpox and shingles now available, I believe that the countries with high vaccination rates could eventually be free of both of the diseases caused by varicella-zoster – ultimately making the chickenpox-shingles duo go the way of the dinosaurs.</p>
<p>[<em>Get our best science, health and technology stories.</em> <a href="https://theconversation.com/us/newsletters/science-editors-picks-71/?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=science-best">Sign up for The Conversation’s science newsletter</a>.]</p><img src="https://counter.theconversation.com/content/168636/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patricia L. Foster is affiliated with the Union of Concerned Scientists and Concerned Scientists at Indiana University.</span></em></p>Chickenpox has largely disappeared from the public’s memory thanks to a highly effective vaccine. But the virus’s clever life cycle allows it to reappear in later adulthood in the form of shingles.Patricia L. Foster, Professor Emerita of Biology, Indiana UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/716812017-09-11T00:40:32Z2017-09-11T00:40:32ZA deadly herpes virus is threatening oysters around the world<figure><img src="https://images.theconversation.com/files/176279/original/file-20170629-16069-z9yweh.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Colleen Burge counts oysters on an oyster aquaculture lease in California. </span> <span class="attribution"><a class="source" href="http://imet.umces.edu/cburge/?gallery=california-field-work-2015">Collin Closek</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Oysters, a delicacy eaten on most coastlines of the world, are a multi-billion-dollar industry. They also are intriguing to study from a health perspective. Oysters feed by filtering tiny plankton from the surrounding water, processing <a href="http://www.habitat.noaa.gov/abouthabitat/oysterreefs.html">up to 50 gallons</a> per oyster daily. In doing so, they improve water quality and make their ecosystems healthier. But the water that they grow in can be filled with disease-causing microorganisms that can affect both oysters and humans. </p>
<p>Today a deadly herpes virus, <a href="http://dx.doi.org/10.1099/vir.0.80382-0">Ostreid herpesvirus 1 (OsHV-1)</a>, is threatening Pacific oysters (<em>Crassostrea gigas</em>), the world’s most popular and valuable oyster species. It is almost certain to spread more widely in our globally connected world. </p>
<p>I know what you’re thinking: “Oysters get herpes??” Yes, and they can also can get sick from other types of pathogens and stresses. But you won’t contract this virus from eating an oyster, whether you enjoy them on the half-shell or cooked. OsHV-1 can infect other bivalve species, like some animal herpes viruses that <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2815145/">can cross species barriers</a>, but it is genetically distinct from other animal herpes viruses and does not infect humans.</p>
<p>With support from the <a href="http://seagrant.noaa.gov/WhatWeDo/CurrentFocusAreas/SustainableFisheriesandAquaculture.aspx">NOAA Sea Grant aquaculture program</a>, I’m working with a diverse team that includes researchers, regulators and outreach specialists in the United States and abroad to better prepare the U.S. oyster industry for the spread of this virus.</p>
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<a href="https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/185175/original/file-20170907-9573-19vm7lm.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"></a>
<figcaption>
<span class="caption">Dead Pacific oyster sampled during a OsHV-1 mortality event this summer in Tomales Bay, California.</span>
<span class="attribution"><span class="source">Colleen Burge</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
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<h2>Deadly and spreading</h2>
<p>Pacific oysters are native to Asia and are the most popular and valued oyster for aquaculture globally. Humans transferred them from their native range to multiple grow-out areas <a href="http://www.fao.org/fishery/culturedspecies/Crassostrea_gigas/en">globally</a>, including France, the United States and Australia. They are the primary species grown on the U.S. West Coast, whereas both wild and cultured Eastern oysters grow on the East and Gulf coasts. In contrast to Eastern oysters, Pacific oysters were relatively resistant to infectious diseases until OsHV-1 emerged in the early 1990s. </p>
<p>Herpes is often fatal to Pacific oysters. That’s especially true for OsHV-1 microvariants – mutant variants of OsHV-1 which are more virulent than the original reference strain. These viruses are <a href="http://dx.doi.org/10.1098/rstb.2015.0213">spreading globally</a>, causing mass mortalities of Pacific oysters. </p>
<p>An OsHV-1 microvariant was first detected in France in 2008, where it <a href="http://dx.doi.org/10.1016/j.virusres.2010.07.011">killed 80 to 100 percent</a> of affected oyster beds. Since then, similar variants have caused mass mortalities of oysters in many <a href="https://doi.org/10.1007/s10499-015-9919-2">European countries</a>. A 2010 outbreak in England killed <a href="https://www.theguardian.com/environment/2010/jul/23/virus-kent-oysters">over eight million oysters</a>.</p>
<p>OsHV-1 microvariants also infect Pacific oysters in New Zealand and Australia. Their spread in Australia, in particular to Tasmania, has <a href="http://www.abc.net.au/news/2016-02-12/the-human-toll-behind-a-deadly-oyster-disease/7164712">crippled the Australian Pacific oyster aquaculture industry</a>. </p>
<h2>Resistance is the best defense</h2>
<p>U.S. oyster growers are strongly concerned about the spread of OsHV-1 microvariants globally. I was part of the team that first detected OsHV-1 in <a href="http://www.int-res.com/articles/dao2005/63/d063p033.pdf">Tomales Bay, California</a>. To date the virus has been detected only in oysters in Tomales Bay and an adjacent bay, and no microvariants have been found yet in U.S. waters. The California OsHV-1 <a href="http://www.int-res.com/articles/dao2006/72/d072p031.pdf">causes mortalities of young Pacific oysters</a>, but is thought to be less virulent than OsHV-1 microvariants.</p>
<p>Given the spread of the OsHV-1 microvariants elsewhere around the world, it may only be a matter of time until they reach U.S. coastal bays or other nonimpacted oyster growing areas. We spent the summer of 2017 conducting experiments in Tomales Bay to determine whether any cultured U.S. oysters species are resistant to OsHV-1, and soon will also conduct laboratory challenges with OsHV-1 microvariants. </p>
<p>Once OsHV-1 is established within a bay, mass oyster deaths typically occur each year during the summer when water temperatures are warm. The situation is analogous to a human who is infected with herpes and periodically get cold sores. Normally the virus is latent (present at a low level) and does not cause cold sores. But after a stressful situation, the virus replicates and cold sores emerge. </p>
<p>Not all oysters die of herpes, and if OsHV-1 behaves like other herpes viruses, it probably remains present latently within infected oysters’ tissues and is reactivated after a stressful event. For oysters, most of the evidence for virus reactivation points to warm summer water conditions.</p>
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<figcaption><span class="caption">Genetic improvements through breeding can improve Pacific oyster survival rates against the OsHV-1 virus.</span></figcaption>
</figure>
<h2>Cultivating oyster resistance</h2>
<p>We can’t vaccinate oysters, and even if antibiotics were effective against viruses, they are not permitted for treating oysters in the United States. Though oysters have an innate immune system that destroys foreign invaders, it lacks an adaptive response, including cells that “remember,” recognize and destroy specific pathogens, as human B or T lymphocytes do. Most vaccines rely on this “immune memory” to be effective. Recent research indicates that oysters’ innate immune systems <a href="https://doi.org/10.1016/j.molimm.2016.09.002">can be stimulated by a virus mimic</a>, but we do not know whether this effect is long-lasting. </p>
<p>The most effective strategy to date has been developing <a href="https://doi.org/10.1016/j.jip.2015.05.010">disease-resistant oyster lines</a>, which can limit both mortalities and oysters’ susceptibility to infection. But this approach involves exposing healthy oysters to the virus – and moving oysters infected with OsHV-1 to naive (disease-free) areas could spread the virus. This means that we can use this approach only in places where OsHV-1 already exists.</p>
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<figcaption>
<span class="caption">Pacific oyster seed ready for planting in Tomales Bay, California.</span>
<span class="attribution"><span class="source">Colleen Burge</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Toward that end, breeding programs in locations including France, New Zealand and Australia are working to develop OsHV-1-resistant Pacific oysters. A complementary approach is to expose oysters and determine genes involved in OsHV-1 resistance. I am currently working with two strains of OsHV-1 – the California virus and a microvariant in France – to determine OsHV-1 resistance genes, including a collaboration with the <a href="https://wwz.ifremer.fr/en/">Ifremer</a> station in La Tremblade, France.</p>
<p>The most effective way to limit damage in new locations from OsHV-1 is to limit its spread. However, we also want to be ready in case OsHV-1 microvariants spread to the United States. Beyond their cash value and the benefits that oysters provide by filtering water, <a href="http://www.habitat.noaa.gov/pdf/value_of_oysters.pdf">oyster reefs provide food and habitat</a> for many commercial fish species. Oysters can’t move themselves out of harm’s way, nor can we move all susceptible oysters, so we need to protect them where they grow.</p><img src="https://counter.theconversation.com/content/71681/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Colleen Burge is currently funded by the NOAA Sea Grant Aquaculture Program and the UMBC-UMB Research and Innovation Partnership Grant Program for her work on OsHV-1. She has been funded in the past by California Sea Grant College Program and National Sea Grant.</span></em></p>Oysters grow in seawater and filter their food from it, so how do you shield them from waterborne diseases? Scientists are working to develop strains that are resistant to a fast-spreading herpes virus.Colleen Burge, Assistant Professor, Institute of Marine and Environmental Technology, University of Maryland, Baltimore CountyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/695392016-11-30T08:27:43Z2016-11-30T08:27:43ZWhy over 45s are at risk of sexually transmitted infections – new findings<figure><img src="https://images.theconversation.com/files/147944/original/image-20161129-10973-1jq9c0v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It's not all ha ha hee hee hee. </span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-498122908/stock-photo-olderly-couple-happiness-romantic-holding-hand-concept.html?src=KkrtiFyAdjdk-6Imgqmt9Q-1-76">Rawpixel.com</a></span></figcaption></figure><p>One consequence of our <a href="http://www.bbc.co.uk/news/uk-34666382">ageing population</a> is that people are now sexually active <a href="https://www.ncbi.nlm.nih.gov/pubmed/20215365">later</a> in life. Combined with a <a href="http://www.telegraph.co.uk/news/uknews/12011714/Divorce-rate-at-lowest-level-in-40-years-after-cohabitation-revolution.html">high rate</a> of older adults divorcing and changing partners, this has created a conducive environment for sexually transmitted infections (STIs) among those in middle age and beyond. </p>
<p>While the under 25s and gay men remain most at risk from STIs, heterosexual adults over 45 have recently seen <a href="https://www.gov.uk/government/statistics/sexually-transmitted-infections-stis-annual-data-tables">increases</a> in <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/401662/2014_PHE_HIV_annual_report_draft_Final_07-01-2015.pdf">HIV</a>, gonorrhoea, herpes, syphilis, chlamydia and genital warts. In England, <a href="https://www.gov.uk/government/statistics/sexually-transmitted-infections-stis-annual-data-tables">rates for chlamydia</a>, the commonest STI, rose 63% among 45-64s between 2011 and 2015 while falling for 15-24s. Yet this is an area of public health that has so far been ignored. </p>
<p>Knowledge about STIs plays a contributing role in reducing the spread of infection. Recent evidence about older adults’ knowledge has largely been confined to HIV, so our understanding of this age group’s knowledge of STIs in general is limited. </p>
<p>In <a href="http://www.rhm-elsevier.com/article/S0968-8080(16)30035-0/abstract">research</a> that I have just co-published, we sought to address this deficiency. By carrying out in-depth interviews with 31 heterosexual men and women in Glasgow aged between 45 and 65, we explored not only what middle-aged adults know about HIV and other STIs but also the social circumstances surrounding that knowledge. </p>
<p>Most of the study participants lived in the most deprived areas in Scotland and had been through divorce, separation or the death of their partner. The interviews led us to four main observations. </p>
<h2>1. STI knowledge is limited</h2>
<p>Most participants had heard about gonorrhoea, syphilis, chlamydia, herpes, general warts and HIV, but beyond recognising the names they were often unsure about any further detailed information. They tended to know more about HIV, often remembering the <a href="http://news.bbc.co.uk/1/hi/programmes/panorama/4348096.stm">national HIV/AIDS campaign</a> in the 1980s and the <a href="http://www.nydailynews.com/entertainment/gossip/celebrities-hiv-positive-aids-article-1.2436964">celebrity deaths</a> in the years before treatment improved. </p>
<p>In keeping with the association of early HIV epidemic with specific risk groups such as gay men and intravenous drug users, the participants often viewed STIs as riskier for other people than for themselves. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147945/original/image-20161129-10949-15sf73k.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">Is ignorance bliss?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/pic-1216477/stock-photo-older-couple-in-love-kisses.html?src=xXtNcIpATQgFNHt5v1eCAQ-1-4">Cate Frost</a></span>
</figcaption>
</figure>
<h2>2. Old stigmas have endured</h2>
<p>The participants had first learned about STIs as teenagers and young adults between the 1960s and 1980s. Most said their sex education at home had been very limited and unclear, with overtones of moral disapproval, and that school sex education was extremely basic and did not cover STIs. As one put it:</p>
<blockquote>
<p>And it was always make sure you don’t get into trouble and I didn’t know what the hell getting into trouble was so that was that.</p>
</blockquote>
<p>The little they had learned about STIs was usually in the context of promiscuous sexual behaviour being condemned and disease being seen as a consequence – with worse stigma where women were concerned. As a result, many participants had gone through life regarding STIs as something to be ashamed of. </p>
<p>During the years when they were in long-term relationships, several participants also did not see it as relevant to improve their knowledge about STIs. And now in middle age, several continued to prefer not to engage with the subject. In the words of one person: </p>
<blockquote>
<p>None of them are anything that I’d want to trawl the internet to find out more about you know; don’t know anybody that’s ever had them or even if they’d admit to it.</p>
</blockquote>
<h2>3. Parents learn about STIs from their children</h2>
<p>We found that parenting had the capacity to influence how much participants knew about STIs. Women in particular had sometimes learned about STIs either to find out about the risks to their children or because their children had been diagnosed with one. </p>
<p>Studies have <a href="http://bmjopen.bmj.com/content/5/3/e007834">previously shown</a> that it is women who mostly provide sex education to their children. Our study is the first to indicate that parenting can also be a source of sex education for the parents themselves. </p>
<h2>4. Knowledge is not the only problem</h2>
<p>Participants who were well informed about STIs did not necessarily practice safer sexual behaviour. Despite the lack of discernible symptoms with many STIs, several participants said they had not sought a test after having unprotected sex with a new partner. Instead they had waited to see if symptoms would appear:</p>
<blockquote>
<p>She’s been sleeping with other people and I let her sleep with me and never used a condom and … then you worry that something happens, that something’s going to come out of it, or are you lucky and I was just praying that something didnae happen.</p>
</blockquote>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/147946/original/image-20161129-10957-1qiigxs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Here’s Johnny!</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/pic-58634179/stock-photo-man-hand-holding-a-condom.html?src=K0L1ZLFWx3G-jHbaMq8omA-2-11">focal point</a></span>
</figcaption>
</figure>
<h2>Next steps</h2>
<p>These findings should be useful for developing interventions for middle-aged adults that help them to learn more about STIs and to make wiser decisions in relation to their sexual health. Public <a href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/142592/9287-2900714-TSO-SexualHealthPolicyNW_ACCESSIBLE.pdf">health policy</a> in the UK makes <a href="http://www.gov.scot/Resource/0048/00484414.pdf">reference</a> to the life-long nature of sexual health, but few health promotion programmes <a href="https://www.ncbi.nlm.nih.gov/pubmed/25921479">directly address</a> older adults taking risks with STIs.</p>
<p>Public health officials need to be aware that people emerging from lengthy relationships often know little about STIs and are poorly equipped to make good decisions about their sexual health. The sense of stigma around STIs with this age group is a barrier that needs to be addressed. Policymakers need to fully engage with gendered attitudes to older women’s sexuality, as well as the full range of lengths and varieties of relationships that people get involved in regardless of their stage in life.</p><img src="https://counter.theconversation.com/content/69539/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jenny Dalrymple is a part-time sexual health nurse for NHS Greater Glasgow and Clyde.</span></em></p>When it comes to sexual health, public information has tended to focus on the young. Time for a change.Jenny Dalrymple, Clinical Academic Research Fellow, Glasgow Caledonian UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/603962016-06-03T09:28:27Z2016-06-03T09:28:27ZShould Zika really stop you going to the Rio Olympics? Here are the facts<figure><img src="https://images.theconversation.com/files/124997/original/image-20160602-23270-cxexrd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cidade maravilhosa.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&searchterm=Rio&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=328110866">Aleksandar Todorovic/Shutterstock.com</a></span></figcaption></figure><p>Over 200 academics from around the world have now signed <a href="http://rioolympicslater.org/">an open letter</a> to the Director-General of the World Health Organisation (WHO) calling for the Olympics and Paralympics in Rio de Janeiro to be postponed or moved to another venue, owing to the threat posed by the ongoing Zika virus pandemic. The evidence concerning Zika virus so far, however, does not justify this course of action. The <a href="http://rioolympicslater.org/">RioOlympicsLater.org</a> authors misunderstand the nature of Zika virus, its history since its discovery in 1947, and also the relative risk posed by Zika virus versus other risks affecting any large event in a tropical country. </p>
<p>The letter begins by referring to the movement of the <a href="http://www.fifa.com/news/y=2003/m=5/news=sars-fifa-executive-decides-relocate-fifa-women-world-cup-2003-87152.html">2003 Women’s World Cup</a> from China to the USA owing to the outbreak of SARS, and the disruption of the <a href="http://www.nytimes.com/2014/11/12/sports/soccer/morocco-wont-host-africa-cup-of-nations-because-of-ebola-fears.html?_r=0">African Cup of Nations</a> schedule during the Ebola epidemic. Neither of these is, however, a valid comparison. </p>
<p>Both <a href="http://onlinelibrary.wiley.com/doi/10.1046/j.1365-3083.2003.01302.x/abstract;jsessionid=5EC933F85FDD4A286A7376B1DEE53824.f02t03">SARS</a> and <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4870382/">Ebola</a> were high-mortality diseases. Also, SARS was a completely new pathogen. Mortality in Zika is very low, and where deaths occur they are often due to complications of <a href="http://www.nhs.uk/Conditions/Guillain-Barre-syndrome/Pages/Introduction.aspx">Guillain-Barre Syndrome</a> rather than a direct result of the virus’s usual symptoms.</p>
<p>The real concern with Zika is <a href="https://theconversation.com/explainer-what-is-microcephaly-and-what-is-its-relationship-to-zika-virus-54049">microcephaly</a> and other damaging effects on foetuses via infection in pregnant women. But the authors’ statement that “Zika virus harms health in ways that science has not observed before” is not correct. <a href="http://www.ncbi.nlm.nih.gov/pubmed/27180225">Recent experiments</a> on laboratory mice, on brain <a href="http://www.ncbi.nlm.nih.gov/pubmed/27118425">organoids</a> (small balls of nervous cells that have <a href="https://www.technologyreview.com/s/535006/brain-organoids/">some of the structure and properties of developing brains</a>) and in brain tissue culture, as well as <a href="http://www.ncbi.nlm.nih.gov/pubmed/27028667">detailed observation</a> of the signs and symptoms of Zika-associated microcephaly in foetuses and infants, show that Zika <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4878297/">can be categorised with other TORCH-syndrome pathogens</a>. </p>
<p>TORCH is an acronym for “TOxoplasma, Rubella, Cytomegalovirus, Herpes”, <a href="http://rarediseases.org/rare-diseases/torch-syndrome/">all agents which cause similar defects in foetuses</a> when the mothers are exposed in pregnancy. Zika is the only TORCH-like pathogen that is spread by mosquito bites, but based on what we have seen so far, there is no reason to think that Zika is particularly virulent. If one insists on drawing comparisons with other diseases, Zika is not the new Ebola, but the new <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4316306/">rubella</a>. </p>
<p>The letter also claims that “most of South Asia and Africa” are “as yet unaffected places”. That is not true either. Many <a href="http://jgv.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.000381#tab2">studies</a>, going back to the 1940s, have shown that humans, and often also monkeys, in several African and Asian countries have antibodies to the Zika virus, and we have direct evidence of Zika circulating in both <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3321795/">West Africa</a> and <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866850/">South East Asia</a> within the last ten years. These studies need to be repeated to determine the current levels, but it is very likely that many parts of the tropical world have already seen Zika virus in the past and there will probably be considerable herd immunity to the local Zika variant in the human population. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124999/original/image-20160602-23291-35owpc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The rubella virus.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-208188670/stock-photo-rubella-german-measles.html?src=fLi9iCGaqf9D3L15SdAqTQ-1-0">decade3d - anatomy online/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>Will that previous exposure be protective against more exotic strains of Zika? The likely answer is “yes”. The Brazilian and African varieties of Zika are about 12-13% different in terms of the <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3289602/">genetic variants accumulated</a> since their last common ancestor. The <a href="http://www.ncbi.nlm.nih.gov/pubmed/25545072">corresponding figure</a> for yellow fever virus, another member of the flavivirus family that includes Zika, is just under 22%. Yet a single <a href="http://www.nhs.uk/Conditions/yellow-fever/Pages/prevention.aspx">yellow fever vaccination</a> will protect against all variants of yellow fever and for a long period of time, so it would be very unusual if exposure to African or South-East Asian Zika did not similarly generate immunity against Brazilian Zika.</p>
<p>Brazil has many of the typical diseases found in the tropical world, including <a href="http://www.who.int/malaria/travellers/en/">malaria</a> and <a href="http://www.nhs.uk/Conditions/dengue/Pages/Introduction.aspx">dengue</a> as well as <a href="http://www.avert.org/professionals/hiv-around-world/latin-america/brazil">levels of HIV</a> about <a href="http://www.avert.org/professionals/hiv-around-world/western-central-europe-north-america/uk">three times higher</a> than the UK. These are things that travellers and athletes need to prepare for. All are clinically more serious than Zika, but none has been proposed as a reason to cancel the event.</p>
<p>There is no major event that is ever 100% safe, and that especially applies to major events in tropical countries. When Zika is seen as it should be, as an insect-borne rubella-like agent, the proper perspective for prevention becomes evident. </p>
<p>Pregnant women, those planning pregnancy and those predisposed to Guillain-Barre syndrome perhaps would be best advised to stay away. Other groups simply need to monitor their health carefully during their visit, use insect repellent and avoid risky sexual behaviour – and thereby also reduce their risk of catching HIV in the process. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/125002/original/image-20160602-23270-1x1gkji.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">
<figcaption>
<span class="caption">Go, but take the precautions.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=NSfsObRvTSMfWCGAbjYbaA-1-11&clicksrc=download_btn_inline&id=295527683&size=medium_jpg&submit_jpg=">lazyllama / Shutterstock.com</a></span>
</figcaption>
</figure>
<p>The <a href="https://www.gov.uk/foreign-travel-advice/brazil/health">travel advice</a> for the topics has not changed much because of Zika, unless you are pregnant or starting a pregnancy soon. The one new important point is that all travellers should <a href="http://apps.who.int/iris/bitstream/10665/204421/1/WHO_ZIKV_MOC_16.1_eng.pdf">abstain from unprotected sex for 60 days</a> following their return, since a Zika infection often does not have symptoms. Everyone who has been in a Zika area needs to assume that they may have been infected. </p>
<p>More importantly, all travellers with a fever or rash, or both, during or after their trip need to go to their doctor. But the first test will be for malaria rather than Zika, because the really important and dangerous tropical diseases must take priority. If these principles are observed, there is no reason why the Olympics cannot take place.</p><img src="https://counter.theconversation.com/content/60396/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Derek Gatherer is affiliated with the WHO Expert Committee On Biological Standardization as a participant in their project "WHO collaborative study to assess the suitability of an interim standard for antibodies to Ebola virus"</span></em></p>Academics have sent an open letter to the World Health Organisation calling for the Olympics to be postponed or moved because of the Zika threat. They’re overreacting.Derek Gatherer, Lecturer, Lancaster UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/579132016-04-21T14:25:50Z2016-04-21T14:25:50ZBreast milk is a marvel of nature but that doesn’t mean adults should drink it to see off disease<figure><img src="https://images.theconversation.com/files/119440/original/image-20160420-25601-1cxpj2y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Don't give it to grandad.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&searchterm=breast%20milk&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=271722359">www.shutterstock.com</a></span></figcaption></figure><p>A woman’s claim that she <a href="http://www.dailymail.co.uk/news/article-3542866/Helen-swears-breast-milk-gave-dying-dad-extra-year-life-right.html">extended her father’s life</a> by more than a year by feeding him expressed milk has led many to ask whether human milk can really delay the growth of cancer. The gold standard nutrition for infants, human milk is not, however, a replacement for conventional medicine in the treatment of adult diseases.</p>
<p>Human milk is perfectly composed for babies, including both nutrient and bioactive components that promote growth and development. <a href="http://www.nhs.uk/Conditions/pregnancy-and-baby/Pages/benefits-breastfeeding.aspx">Official guidance</a> in the UK recommends exclusive human milk feeding for the first six months of life. Continued breastfeeding for one to two years or longer is then endorsed by various organisations, <a href="http://www.who.int/topics/breastfeeding/en/">including the WHO</a>.</p>
<h2>Changeable milk</h2>
<p>The composition of human milk varies. <a href="http://www.cell.com/trends/biochemical-sciences/fulltext/S0968-0004%2816%2900045-1">Research</a> shows that it changes within feeds, across the day, across lactation, and between different women. This variability benefits the infant as they grow and develop. </p>
<p>The first fluid produced after delivery is colostrum. It is produced in low quantities and is rich in compounds that boost the immune system (such as leukocytes, secretory immunoglobulin A, and lactoferrin), as well as others that support growth and development (like epidermal growth factor). However, colostrum is relatively low in lactose, potassium, and calcium, leading <a href="http://ssu.ac.ir/cms/fileadmin/user_upload/Mtahghighat/tfood/ARTICLES/milk/Human_Milk_Composition.pdf">researchers</a> to conclude its function is not primarily to provide nutrition. </p>
<p>Within days the composition changes, lactose increases, marking the production of what many call “<a href="http://ajcn.nutrition.org/content/53/5/1197.short">transitional milk</a>”. This change in the milk can be delayed if the baby is delivered preterm or if the mother has a metabolic condition or is obese.</p>
<p>Across the next few weeks, milk production increases rapidly. This is to support the changing nutritional and developmental needs of the growing infant. Within a month to six weeks, the milk becomes fully mature. </p>
<h2>Complex stuff</h2>
<p><a href="http://ssu.ac.ir/cms/fileadmin/user_upload/Mtahghighat/tfood/ARTICLES/milk/Human_Milk_Composition.pdf">Mature milk</a> provides around 65 to 70 calories per 100g, which come from about 4g of fat, 7g of carbohydrate, and 1g of protein. But this composition is constantly changing. The variation in calories is primarily due to differences in fat content. Fat content is significantly lower at night and morning compared with afternoon or evening milk. It also varies within the feed itself. Milk at the end of the feed has <a href="https://www.researchgate.net/profile/Chantal_Lau/publication/12944835_Feeding_strategies_for_premature_infants_Beneficial_outcomes_of_feeding_fortified_human_milk_versus_preterm_formula/links/0deec536d7c743b2d0000000.pdf">higher levels</a> than the initial flow.</p>
<p>The composition of milk also varies with maternal diet, especially the amount and type of fatty acid. Many women in developed countries aren’t getting enough fatty acid – important for infant brain development – in their diet and this affects the composition of their breast milk. For example, low levels of docosahexaenoic acid (DHA) – an omega 3 fatty acid – consumed by North American mothers translates to low levels in their milk. This has led some <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3566653/">researchers</a> to suggest that mothers should take appropriate supplements. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=416&fit=crop&dpr=1 600w, https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=416&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=416&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=523&fit=crop&dpr=1 754w, https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=523&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/119449/original/image-20160420-25615-1udeamm.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=523&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some mothers might benefit from taking fatty acid supplements.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&search_tracking_id=TU9ndqjQrevZ5pNRYs_6nA&searchterm=fish%20oil%20supplement&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=288277154">www.shutterstock.com</a></span>
</figcaption>
</figure>
<h2>More than just nutrition</h2>
<p>But human milk doesn’t just contain nutrition; it contains a variety of compounds with medicinal qualities that are important for the baby’s survival. These “growth factors” are numerous and have wide-ranging effects. For instance, epidermal growth factor is important for the development and repair of the gastrointestinal tract. Insulin-like growth factors are critical in stimulating growth and development, with high levels of some <a href="https://www.researchgate.net/publication/16992978_Immunoreactive_Somatomedin-CInsulin-Like_Growth_Factor_I_and_Its_Binding_Protein_in_Human_Milk">linked</a> to neural, and cochlea development in the ear. There are many growth factors, and they affect many important functions, including the development of the blood vessels, metabolism, intestinal system, nervous system, and endocrine (hormone) system. </p>
<p>Human milk also has important immune impacts, protecting against inflammation and infection. Oligosaccharides (a carbohydrate) encourage the growth of organisms that plays an essential role in early bacterial colonisation of the intestine which have important impacts on gut health and general well-being in later life, while also reducing vulnerability to some pathogens, such as <a href="http://jid.oxfordjournals.org/content/190/10/1850.full">noroviruses</a>.</p>
<h2>Not for sharing</h2>
<p>Containing a variety of <a href="http://www.bbc.co.uk/schools/gcsebitesize/science/21c_pre_2011/disease/diseaseresistancerev4.shtml">white blood cells</a>, human milk stimulates the development of the infant immune system while providing protection from germs. <a href="http://adc.bmj.com/content/84/5/381.full">Research</a> reveals that such transmission, however, opens up the potential for infection with HIV, syphilis, hepatitis and herpes, among other viruses, which can pass along with these cells.</p>
<p>This viral transmission, along with the risk of contamination with bacteria and toxins, creates a need for careful management of milk sharing <a href="http://www.bmj.com/content/350/bmj.h1485">and selling</a>. The nutrient and bioactive compounds are affected by the mother’s consumption of food, drink, medicines and illicit drugs. The presence of toxins and contaminants are introduced by a mother’s environmental exposure, as well as during expression and storage of the milk. Expressing and pasteurising milk <a href="http://ajcn.nutrition.org/content/96/3/544.full.pdf+html">changes its composition</a> which can reduce or even eliminate some bioactive components. </p>
<p>Such impacts make oversight crucial for babies fed with another mother’s milk, but also mean a careful approach is needed by those adults who think human milk might hold medicinal value. While a liquid gold, awareness of the risks as well as the benefits of human milk is crucial, both for adult and infant consumers.</p><img src="https://counter.theconversation.com/content/57913/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sarah Steele 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>Most people are aware of the benefits of breastmilk, but few are aware of the risks.Sarah Steele, Queen Mary University of LondonLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/321602014-10-27T03:31:36Z2014-10-27T03:31:36ZHealth Check: the STI check-up – warts and all<figure><img src="https://images.theconversation.com/files/62613/original/99xp9hch-1414044091.jpg?ixlib=rb-1.1.0&rect=0%2C267%2C5760%2C3095&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Technology has done away with the need to insert swabs into the male urethra and speculums into the vagina. Instead, blood and urine are tested.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-216141157/stock-photo-medical-urine-test-close-up.html?src=pp-same_artist-216145360-_cx5M619eKLmHluUfhtomw-3">In Tune/Shutterstock</a></span></figcaption></figure><p>Sexuality is a means of pleasure, fulfilment and intimate connection with other humans. But it can also be a source of anguish. So it’s perhaps no surprise that of all the areas in health care, the “STI check” is one of the most fraught. </p>
<p>An STI check is one or more tests performed on a person who has no symptoms but is potentially at risk of having one or more sexually transmitted infections. </p>
<p>If you have symptoms – such as vaginal or urethral discharge; lower abdominal, pelvic, testicular or genital pain or itch; lumps, warts or ulcers in the genital area; unusual vaginal bleeding; painful urination; or anal symptoms if you have had anal sex – then the context changes to being a diagnostic assessment. </p>
<p>STI checks for asymptomatic people fall into the realm of “opportunistic health screening” – think blood pressure checks for hypertension, blood sugar tests for diabetes and other scenarios where you’re offered a test but have no symptoms. However, the STI check is not one-size-fits-all, nor does a “full STI check” actually test for all possible STIs.</p>
<p>So, which STIs are relevant to your own personal STI check? These are determined by your sexual history, what is known about the patterns of STIs in different populations, as well as the technical reliability of the tests. </p>
<p>The STIs tested include one or more of the following: <a href="https://playsafe.health.nsw.gov.au/sti/chlamydia">chlamydia</a>, <a href="https://playsafe.health.nsw.gov.au/sti/gonorrhoea">gonorrhoea</a>, <a href="https://playsafe.health.nsw.gov.au/sti/syphilis">syphilis</a>, <a href="https://playsafe.health.nsw.gov.au/sti/hepatitis-b">hepatitis B</a> and <a href="https://playsafe.health.nsw.gov.au/sti/hiv-aids">HIV</a> (human immunodeficiency virus). In some populations, it might also include <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Hepatitis_C_the-facts">hepatitis C</a>, <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Trichomoniasis?open">trichomoniasis</a> or <a href="https://playsafe.health.nsw.gov.au/sti/bacterial-vaginosis">bacterial vaginosis</a>. </p>
<p>Here’s what your doctor or nurse might ask you to help guide the STI check: </p>
<ul>
<li>your age and gender</li>
<li>whether you are Aboriginal or Torres Strait Islander, or a recent migrant (if so, from where), or travelled recently</li>
<li>your recent sexual encounters, including the number of partners you have had in the past three months</li>
<li>the gender of your sexual partners ever (male, female, both)</li>
<li>the nature of your sexual practices (vaginal intercourse, anal intercourse, oral sex)</li>
<li>whether and how often you have used condoms</li>
<li>whether you’ve had an STI check before and when</li>
<li>whether you’ve ever been diagnosed with an STI. </li>
</ul>
<p>To give a fuller picture of STI risk, you could be asked whether you have ever paid or been paid for sex, been in gaol, injected substances, or had tattoos or piercings done overseas or at home.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62705/original/d4h8d7p3-1414125623.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">For heterosexuals up to 29 years, an annual chlamydia test is recommended.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-177322637/stock-photo--young-woman-reading-brochure-in-doctor-s-waiting-room.html?src=B0L3JUlROUvWFrA1eqQqMQ-1-27">diplomedia/Shutterstock</a></span>
</figcaption>
</figure>
<p>Although potentially daunting, most people believe that their GP is the right person with whom to discuss their sexual health. A GP or nurse who makes you feel comfortable is likely to be one who explains confidentiality, asks questions sensitively and gives you clear explanations of what the STI check will involve. They will also explain that choosing whether to answer questions is up to you. </p>
<p>When it comes to the tests, the good news is that technology has done away with the once-uncomfortable, or downright painful, swab up into the urethra of men, or the need for a woman to have a speculum inserted into her vagina.</p>
<p><a href="https://playsafe.health.nsw.gov.au/sti/chlamydia">Chlamydia</a> and <a href="https://playsafe.health.nsw.gov.au/sti/gonorrhoea">gonorrhoea</a> tests can be done on urine samples in men and women or self-collected vaginal swabs in women. If there is a concern about anal sex transmission, you can collect your own swab from your rectum. Gay men having unprotected oral sex are advised to allow the doctor or nurse to collect a throat swab.</p>
<p><a href="https://playsafe.health.nsw.gov.au/sti/syphilis">Syphilis</a>, <a href="https://playsafe.health.nsw.gov.au/sti/hepatitis-b">hepatitis B</a> and <a href="https://playsafe.health.nsw.gov.au/sti/hiv-aids">HIV</a> are tested for on blood samples, as is <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Hepatitis_C_the-facts">hepatitis C</a> (this is an infection mainly passed on through sharing needles).</p>
<p><a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Trichomoniasis?open">Trichomoniasis</a> mainly affects Aboriginal and Torres Strait Islander women living in remote and regional Australia and can be tested for on a urine sample or vaginal swab.</p>
<p><a href="https://playsafe.health.nsw.gov.au/sti/bacterial-vaginosis">Bacterial vaginosis</a> (BV) is not strictly an STI but is much more prevalent in women who have sex with women. BV is diagnosed via a vaginal swab, usually collected by the doctor or nurse.</p>
<p>If you need an examination, it should be explained beforehand that you can request a chaperone in the room (such as a nurse present while the doctor examines you). A curtain and sheet for privacy are standard. </p>
<p>The recommended frequency of STI checks also varies. In heterosexuals up to 29 years, an annual chlamydia test alone is recommended. In men who have sex with men who have additional risk factors (such as any unprotected anal sex, ten or more partners in six months) testing every three months is recommended. Some people want an STI check when they embark on a new relationship and can request one.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/62706/original/9t5btyyg-1414126068.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Your doctor or nurse will ask you whether and how often you have used condoms.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-168231869/stock-photo-safe-sex-concept-hand-with-condom.html?src=iLU5QfWoUDMCZ-e1aawxng-1-118">chingyunsong/Shutterstock</a></span>
</figcaption>
</figure>
<p>It might be helpful to know that two of the most common STIs are <em>not</em> included in the STI check: <a href="http://www.health.gov.au/internet/immunise/publishing.nsf/Content/immunise-hpv">human papillomavirus</a> (HPV) and <a href="http://www.cdc.gov/std/herpes/stdfact-herpes.htm">herpes simplex virus</a> (HSV). This is related to the reliability of the tests and the way in which these infections spread in populations, making routine test unhelpful. If you have particular concerns about these infections, because of a known contact for example, it’s best to discuss this specifically with your doctor.</p>
<p>Follow-up is an important part of the STI check. Discussing the most reliable way of contacting you is part of pre-STI check counselling. You might opt for an SMS, or prefer a return appointment to go through everything. </p>
<p>If you do have a positive test, appropriate treatment will be recommended, supportive counselling provided, and notifying sexual partners will be discussed. Depending on the STI, you will be asked to try to contact sexual partners from the past two to 12 months. Your doctor, or a public health unit, can help and it can be done anonymously. </p>
<p>For some STIs, including the most common – chlamydia – you will be asked to re-test some time after treatment to make sure it has cleared and you are not reinfected. Many STIs are notified to central health surveillance units, an important part of managing communicable diseases.</p>
<p>STI checks are a way of being proactive and preventive when it comes to health. If sex and health are an important part of your life, then try to think of the STI check as something that will contribute to your enjoyment of both.</p><img src="https://counter.theconversation.com/content/32160/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Melissa Kang 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>Sexuality is a means of pleasure, fulfilment and intimate connection with other humans. But it can also be a source of anguish. So it’s perhaps no surprise that of all the areas in health care, the “STI…Melissa Kang, Senior Lecturer, Department of General Practice, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/165432013-07-31T05:35:03Z2013-07-31T05:35:03ZExploding herpes virus blasts DNA into human cells<figure><img src="https://images.theconversation.com/files/28360/original/5ft8mh54-1375185535.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1024%2C683&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Can't handle the pressure.</span> <span class="attribution"><span class="source">Stefanotshcki!</span></span></figcaption></figure><p>Some viruses are like tiny powerhouses. They are only nanometers in size, but their insides are jam-packed with DNA that is so highly pressurised that it explodes out during infection.</p>
<p>Herpes simplex 1 (HSV-1), the virus that causes those painful lip blisters, or cold sores, for example, has an internal pressure eight times higher than that of a car tyre. And the virus uses that pressure to literally blast its infectious DNA into human cells. </p>
<p>While scientists have suspected that herpes viruses did this during infection, for the first time we’ve been able to see and measure it. And the discovery of this pressure-driven infection mechanism — the first in a human virus — opens the door to new treatments for viral infections.</p>
<h2>A controlled explosion</h2>
<p>HSV-1 is one of a number of DNA viruses in the herpes family. As well as cold sores, members of the herpes family cause chickenpox and <a href="http://www.nhs.uk/Conditions/Shingles/Pages/Introduction.aspx">shingles</a> (varicella-zoster) and <a href="http://www.nhs.uk/conditions/genital-herpes/pages/introduction.aspx">genital herpes</a> (HSV-1 and HSV-2), as well as many forms of cancer, such as Hodgkin’s lymphoma (Epstein–Barr virus or HHV-4). Some forms of herpes viruses, such as Herpes B, are lethal to humans.</p>
<p>Herpes simplex viruses comes in two forms: type 1 and type 2. It’s a very common infection and remains latent, although it can be activated - causing blisters or cold sores. </p>
<p>The HSV-1 virus enters the body by penetrating the outer cell membrane during infection, then travels to the cell’s nucleus where it “docks” in a small hole in the nuclear membrane and ejects its DNA load. </p>
<p><a href="http://pubs.acs.org/doi/abs/10.1021/ja404008r">Our research</a>, published in the Journal of the American Chemical Society, shows how the herpes virus does this. The virus contains DNA that is hundreds of times longer than the diameter of its tough outer shell which allows it to build up enough pressure to blast its DNA into the cell.</p>
<p>Many viruses pack long stretches of nucleic acid (DNA or RNA) into their protein shells. HSV-1 contains double-stranded DNA that is 400 times longer. All DNA and RNA consist of a long molecule (a polymer) which has a lot of negative charge. In viruses where the DNA is packaged tightly, the negative charges on opposite DNA strands cause strong repulsion (similar to bringing two magnets of the same polarity next to each other).</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=315&fit=crop&dpr=1 600w, https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=315&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=315&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=396&fit=crop&dpr=1 754w, https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=396&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/28361/original/vjykk9y3-1375185808.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=396&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Before and after.</span>
<span class="attribution"><span class="source">Alex Evilevitch</span></span>
</figcaption>
</figure>
<p>The DNA gets packaged so tightly that it bends upon itself, resulting in repulsive forces that exert tremendous energy and pressure on its outer shell. This internal pressure powers the ejection of DNA. </p>
<p>Along with colleagues, we discovered that we could degrade a protein in the virus called UL6. The protein acts like a plug and blocks DNA from being ejected. By degrading it we triggered the HSV-1 to eject its DNA. From this we could measure how much DNA was released and the pressure it took to do it.</p>
<p>It’s already known that several viruses that infect bacteria, called bacteriophages, use this high-pressure mechanism to shoot their DNA into bacteria. But despite billions of years of evolution separating human viruses and bacteriophages, our research shows that evolution has preserved this effective technique as a key step in viral infection — making it a desirable target for future treatments to defeat herpes viruses and other viruses that work the same way.</p>
<h2>Targeting the virus in a new way</h2>
<p>Current treatments for viral infections are highly specialised. They target proteins specific to a certain virus. But the viruses responsible for influenza, AIDS, and other infections that affect millions of people annually, for example, are quick to develop resistance to drugs that target their viral proteins. Through genetic mutations, these proteins can quickly disguise themselves and evade anti-viral drugs. This has led to a search for vulnerabilities that don’t involve viral proteins.</p>
<p>Also, no virus mutations can affect the negative charges in DNA. Designing drugs that interfere with viruses that use this mechanism - by reducing their DNA pressure - could limit drug resistance that develops because of rapid virus DNA mutations.</p><img src="https://counter.theconversation.com/content/16543/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alex Evilevitch and fellow researchers received funding from the National Science Foundation, the Swedish Research Council, the National Institutes of Health and the Mellon College of Science Dean's Fund</span></em></p>Some viruses are like tiny powerhouses. They are only nanometers in size, but their insides are jam-packed with DNA that is so highly pressurised that it explodes out during infection. Herpes simplex 1…Alex Evilevitch, Associate Professor of Physics, Carnegie Mellon UniversityLicensed as Creative Commons – attribution, no derivatives.