Addiction Crisis

<p></p><p>Hear firsthand from individuals struggling with addiction and follow the cutting-edge work of doctors and scientists as they investigate why addiction is not a moral failing, but a chronic, treatable medical condition. Easy access to drugs like heroin, fentanyl, and even prescription medications like OxyContin has fueled an epidemic of addiction—the deadliest in U.S. history. Now, science is revealing how addiction affects the brain, and top experts are gathering evidence about how we should address our drug problem, from embracing evidence-based treatments, to rethinking public policies. (Premiered October 17, 2018)</p><p></p>

<p>Discover how opioid addiction affects the brain and how evidence-based treatments are saving lives.</p>

Addiction

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<p>In Western New York, public health officials have organized a task force that’s giving people who suffer from opiate use disorder a new beginning.</p>

Restoring Hope: Fighting the Opioid Crisis in Buffalo

Could Cadaver Organs Save Your Life? Hero

<p>As the number of people who need organs goes up, the number of donors has plateaued, meaning we need to find new solutions. Dr. Doris Taylor and her team’s answer: custom-building organs from cadavers.</p>

<p>Custom-built lungs, livers, kidneys and hearts could someday save thousands of lives.</p>

Could Cadaver Organs Save Your Life?

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Body & Brain

Koch Foundation

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      <div class="rich-text"><p>Much of the meat on our dinner plates contains a not-so-secret ingredient: antibiotics.</p><p>When these bacteria-fighting compounds were first introduced nearly a century ago, they were hailed as miracle drugs, capable of halting the spread of human infections that once spelled certain death. Nowadays, however, around three-quarters of the antibiotics in use are administered to mostly healthy livestock and poultry, which collectively consume <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6510296/">about 150,000 tons</a> of these drugs each year.</p><p>This pharmaceutical feeding frenzy comes with <a href="https://medium.com/hhmi-science-media/a-taste-of-our-own-medicine-f7fbf9896288">dire consequences</a>. Where use of antibiotics increases, so too does the number of bacteria that can resist them—including in some of the countries least equipped to combat obstinate infections.</p></div>
  

  
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      <div class="rich-text"><p>Today, in the journal <i>Science,</i> a first-of-its kind <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aaw1944">global analysis</a> shows that, in the past 20 years, the number of antibiotic-resistant pathogens has skyrocketed in food animals—especially in certain regions of Asia, which is home to more than half of the world’s chickens and pigs. The study, which compiled data from more than 900 surveys from around the world, portends the possibility that multidrug-resistant infections may once again spread unchecked in animals and humans alike.</p><p>“[These authors] have done a terrific job of making sense of the available data,” says <a href="https://www.pewtrusts.org/en/about/experts/karin-hoelzer">Karin Hoelzer</a>, an expert in foodborne pathogens at the Pew Charitable Trusts who wasn’t involved in the study. “The key takeaway is that antimicrobial resistance is a really big threat [around the world]...and animal agriculture clearly has an important role to play.”</p>
            <figure class="richtext-image full-width"><img alt="iStock-470509418.jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/iStock-470509418.width-800.jpg"/><figcaption><p>Most agricultural antibiotics are used in healthy animals, often as growth enhancers or prophylactics. Image Credit: omersukrugoksu, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>Soon after antibiotics first came onto the scene in 1928, they were introduced into farm animal feed. At first, the drugs served the same therapeutic purpose they did in humans, combating illness on an as-needed basis. But farmers were quick to notice antibiotics’ surprising side effect of triggering weight gain in healthy livestock and poultry—a biological quirk that beefed up the yield of marketable meat.</p><p>Nowadays, only a minority of agricultural antibiotics are administered as a treatment for disease, while the rest are consumed by healthy animals as growth enhancers and infection-preventing prophylactics, often in place of good hygiene, says study author <a href="https://usys.ethz.ch/en/people/profile.MjE1OTUx.TGlzdC8yODUyLDMyMDE5NzIyMg==.html">Thomas Van Boeckel</a>, an epidemiologist at the Swiss Federal Institute of Technology in Zurich.</p><p>These practices do more than cut agricultural corners. Any time an antibiotic is used, it gives microbes the opportunity to develop resistance—the ability to subvert a drug’s lethal effects. Decades of research have shown that bacteria can evolve resistance far faster than scientists can discover or synthesize new drugs: In the world of antimicrobial warfare, humans are dramatically outpaced.</p></div>
  

  
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      <div class="rich-text"><p>Increasingly untreatable infections imperil food animals and, by extension, the world’s meat supply. And if and when these “superbugs” transfer the genes that confer resistance to microbes that do harm to humans, the repercussions can be even more severe.</p><p>“The health of animals, humans, and the environment are <a href="https://www.asmscience.org/content/journal/microbiolspec/10.1128/microbiolspec.ARBA-0009-2017">intricately linked</a>,” says <a href="http://contacts.ucalgary.ca/info/chs/profiles/1-5567466">Karen Tang</a>, a social epidemiologist and medical researcher at the University of Calgary in Canada who was not involved in the study.</p><p>For these reasons and more, several world powers, including the <a href="https://www.fda.gov/animal-veterinary/cvm-updates/fda-announces-implementation-gfi-213-outlines-continuing-efforts-address-antimicrobial-resistance">United States</a>, <a href="https://qz.com/1480983/antibiotic-resistance-on-farms-could-be-slowed-by-canadas-new-regulations/">Canada</a>, and the <a href="https://www.theguardian.com/society/2018/oct/25/european-parliament-approves-curbs-on-use-of-antibiotics-on-farm-animals">European Union</a>, have passed legislation curtailing the use of antibiotics in livestock and poultry. But in most low- and middle-income countries in Asia, Africa, and South America, where disease surveillance remains sparse, there are no formal measures in place to tabulate the true extent of antibiotic resistance—let alone regulations to curb its spread, Van Boeckel says. That’s especially concerning, he says, considering the appetite for meat in these regions is expanding at an unprecedented rate.</p><p>To fill in some of these gaps, a team led by Van Boeckel and <a href="https://usys.ethz.ch/en/people/profile.MjQ0OTc4.TGlzdC82MzcsMzIwMTk3MjIy.html">João Pires</a>, a clinical microbiologist at the Swiss Federal Institute of Technology, decided to appraise antibiotic resistance on a global scale. In the absence of surveillance data, the researchers turned to point prevalence surveys, which document snapshots of infection rates at a single point in time.</p><p>Using data from 901 of these surveys, the team tabulated the number of animal antibiotics to which at least 50 percent of bacterial strains were resistant—a cutoff that indicated a drug would likely fail the majority of the time. The analysis focused on four common foodborne pathogens: <i>E. coli</i>, <i>Salmonella</i>, <i>Campylobacter</i>, and <i>Staphylococcus aureus</i>.</p><p>The results weren’t surprising, Van Boeckel says, but they were grim. Between 2000 and 2018, the proportion of “failing” antibiotics nearly tripled in chickens and pigs and doubled in cattle. Among these drugs were several that also play critical roles in human medicine, such as ciprofloxacin and erythromycin. “I’m very worried about the future of these drugs,” Pires says.</p>
            <figure class="richtext-image full-width"><img alt="iStock-185060260.jpg" class="richtext-image full-width" height="531" width="800"
            src="/wgbh/nova/media/images/iStock-185060260.width-800.jpg"/><figcaption><p>Methicillin-resistant <i>Staphylococcus aureus, </i>one of many strains of drug-resistant bacteria that can pass from livestock to humans. Image Credit: zmeel, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>The drugs most commonly used in food production, such as penicillin, also tended to harbor the highest rates of resistance. That trend hints strongly at the link between antibiotic use and resistance—something that’s never been demonstrated on such a large scale over a long period of time, says <a href="https://www.bdi.ox.ac.uk/Team/catrin-moore">Catrin Moore</a>, a microbiologist at the University of Oxford’s Big Data Institute who authored a <a href="https://science.sciencemag.org/cgi/doi/10.1126/science.aay9652">perspective piece</a> on the study, but didn’t contribute directly to its findings. Where drugs go, she says, resistance follows.</p><p>When the team superimposed its data onto a global map, they noted several “hotspots” of multidrug resistance in Asia overlapped with areas where antibiotic use is <a href="https://science.sciencemag.org/content/357/6358/1350.full">expected to increase</a>. Many of these hotspots were also close to major urban centers, likely reflecting how local demand for meat, as well as accessibility to veterinary drugs, boost antibiotic use, Van Boeckel says.</p><p>Though these regions warrant further attention, the paper’s resistance map is far from comprehensive, Moore says. “These models are only ever as good as the data that goes into them,” she says. “This is a platform on which to build even better maps of antimicrobial resistance.”</p><p>Still, it’s clear that “a huge amount of work” went into this study, says Tang, who praised the paper as exciting and important.</p><p>Van Boeckel acknowledges that there’s no replacement for systematic surveillance, which is the gold standard for tracking infection. But point prevalence surveys, he says, “are the best thing we have available. The alternative would be nothing.”</p>
            <figure class="richtext-image full-width"><img alt="iStock-1023277838.jpg" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/iStock-1023277838.width-800.jpg"/><figcaption><p>Much of the meat that ends up on dinner plates comes from animals that were raised on a steady supply of antibiotics. Image Credit: pack_zero, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>And what’s been presented so far, he says, is already cause for immediate action. Regulations passed in high-income countries “become pointless if similar interventions aren’t implemented in low- and middle-income countries,” he says.</p><p>Of course, there’s no silver bullet against a problem this widespread. Two years ago, Van Boeckel co-authored <a href="https://science.sciencemag.org/content/357/6358/1350.full">another publication</a> outlining three potential strategies to wean the world’s livestock and poultry off antibiotics: enforcing caps on the use of antibiotics in agriculture, taxing their use in veterinary contexts, and reducing meat consumption. The third recommendation, which calls for a potentially dramatic shift in diet, is an especially delicate one, Van Boeckel says. Moore agrees, highlighting the importance of cultural sensitivity in guiding such transitions.</p><p>All this will also require coordinated assistance from high-income countries—especially from those that have had success in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050507/#r12">cutting antibiotics out of animal feed</a>, Van Boeckel says. But he and Pires both hope that the global stakes are clear: No one will be protected if we don’t act together, they say.</p><p>The urgency of the situation can’t be overstated, Hoelzer says. As antibiotic resistance grows, the number of treatment options for both animals and humans rapidly dwindles. “Our options are limited,” she says. “This is a global issue that concerns us all.”</p></div>
  

  
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<p>That spells trouble for the entire planet.</p>

Antibiotic-resistant bacteria in farm animals are rising in low- and middle-income countries





  
      <div class="rich-text"><p>About 20 years ago, New Jersey and Pennsylvania began to replace highway toll booths with E-ZPass plazas. It was a major transformation: No longer required to stop and fish for change, motorists sailed down turnpikes instead of idling in long lines. The switch cleared the region of congestion and stop-and-go-traffic—as well as the plumes of pollutants they tend to produce.</p><p>By the end of 2001, both states’ transitions to open-road tolling were nearly complete. And in the months following, rates of premature births within a mile of revamped plazas <a href="https://www.macfound.org/media/files/HHM_Research_Brief_-_Living_Along_a_Busy_Highway.pdf">began to drop</a>.</p><p>Researchers have long suspected that the effects of air pollution can transcend generations, passing from mother to child as early as the first stages of pregnancy. But the details of this insidious inheritance have been tough to pin down, in part because scientists haven’t had a good way to demonstrate that pollutants can breach the placenta—the barrier around the fetus that exists throughout gestation.</p></div>
  

  
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      <div class="rich-text"><p>That might now be changing. <a href="https://www.nature.com/articles/s41467-019-11654-3">Reporting today</a> in the journal <i>Nature Communications</i>, a team of researchers has detected particles of black carbon—the sooty black material emitted when fossil fuels are burned—on the side of the placenta that faces the fetus.</p><p>The study, which measured particulates in placental samples taken after pre- or full-term birth, doesn’t prove that fetuses are actually <i>internalizing</i> the pollutants their mothers breathe. But it’s some of the strongest evidence yet that there’s direct exposure, says <a href="https://scholar.princeton.edu/jcurrie/home">Janet Currie</a>, a health economist at Princeton University who was not involved in the study. “This is the smoking gun,” she says.</p>
            <figure class="richtext-image full-width"><img alt="iStock-157313230.jpg" class="richtext-image full-width" height="523" width="800"
            src="/wgbh/nova/media/images/iStock-157313230.width-800.jpg"/><figcaption><p>Black carbon is emitted by gas and diesel engines, coal-fired power plants, and other sources that burn fossil fuel. Image Credit: milehightraveler, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>If you’re reading this, you’ve breathed in black carbon, one of the many pollutants that fall under the category of particulate matter. During the combustion process, toxic chemicals tend to cling to bits of black carbon, which then drift into the atmosphere—and into human noses and mouths.</p><p>Where these particles go, <a href="https://www.ccacoalition.org/en/slcps/black-carbon">adverse</a> <a href="https://academic.oup.com/aje/article/167/3/280/132182">health outcomes</a> <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3385429/">seem</a> <a href="https://www.sciencedirect.com/science/article/pii/S0013935118306455?via%3Dihub#!">to follow</a>. Adults in regions with smoggy skies have more respiratory disease, heart problems, and cancer. Kids that grow up in these areas are at higher risk of asthma and perform worse on cognitive tests. Even babies born to mothers exposed to air pollution are more likely to be premature and weigh too little at birth.</p><p>These patterns have hinted that black carbon’s effects go far beyond the lungs, says study author <a href="https://www.uhasselt.be/fiche?email=hannelore.bove">Hannelore Bové</a>, an environmental scientist at Hasselt University in Belgium. But most studies on air pollution are epidemiological, drawing on broad trends in health and disease on population-wide scales. To truly pin down cause and effect, she says, researchers need a way to track the particles themselves—and show that they’re able to access the rest of the body.</p><p>A few years ago, when Bové was a graduate student, no such technique existed. So she came up with one.</p></div>
  

  
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      <div class="rich-text"><p>With the help of her colleagues, Bové discovered that black carbon glows when it’s hit with short, fast pulses of certain wavelengths of light. Against a backdrop of human tissue, the particles look like “white dots,” she says. “It’s really easy to distinguish.”</p><p>Recently, Bové and her colleagues used their technique to show that black carbon is capable of <a href="https://www.atsjournals.org/doi/full/10.1164/rccm.201704-0797OC?url_ver=Z39.88-2003&amp;rfr_id=ori%3Arid%3Acrossref.org&amp;rfr_dat=cr_pub%3Dpubmed">infiltrating the kidneys</a>, passing out of the body in the form of urine. Curious to see where else the particles might end up, the team turned its attention to the placenta.</p><p>In their new paper, the researchers examined placentae from 28 women enrolled in the ongoing <a href="https://academic.oup.com/ije/article-lookup/doi/10.1093/ije/dyw269">ENVIR<i>ON</i>AGE birth cohort study</a>, which recruits mothers to donate samples of tissue, including the placenta, after they give birth. Within this pool, 10 participants spent the entirety of their pregnancy living in residential areas in Belgium with relatively high black carbon levels, while another 10 women had experienced only minimal exposure. Unsurprisingly, Bové says, the placentae of the women in the first group lit up with black carbon, with some containing up to 35,000 particles per cubic millimeter of tissue. (Given that this study is the first of its kind, it’s hard to know what those numbers mean, Bové says, but more probably isn’t better.)</p><p>But black carbon was also detectable in the placentae of the women living in regions with less pollution, albeit in smaller amounts. In fact, the particles were present in the tissue of all 28 women in the study, including five who had given birth preterm—suggesting that pollutants can work their way into these tissues as early as the first trimester, when the fetus is <a href="https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-first-trimester">most vulnerable</a>.</p>
            <figure class="richtext-image full-width"><img alt="Clinical Epigenetics Review.jpg" class="richtext-image full-width" height="528" width="800"
            src="/wgbh/nova/media/images/Clinical_Epigenetics_Review.width-800.jpg"/><figcaption><p>An image of placental tissue containing black carbon particles, shown in white and indicated by white arrowheads. The scale bar is 40 micrometers long. Image Credit: Saenen et al, Clinical Epigenetics, 2019</p><div class="credit"><p></p></div></figcaption>
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            <p>Given the global ubiquity of air pollution, it’s not surprising to see black carbon particles in every sample, says <a href="https://www.sph.emory.edu/faculty/profile/#ajgaski">Audrey Gaskins</a>, an epidemiologist specializing in fertility at Emory University who wasn’t involved in the study. “I would’ve been more shocked if they only found it in some,” she says.</p><p><a href="https://www.mailman.columbia.edu/people/our-faculty/fpp1">Frederica Perera</a>, director of the Columbia Center for Children&#x27;s Environmental Health, praises the study for its rigor, but notes that it’s just a first step. The number of women sampled in the study was small, she says. And the illumination technique couldn’t reliably detect particles below 2.9 micrometers in diameter, despite the fact that ultrafine particles <a href="https://www.health.ny.gov/environmental/indoors/air/pmq_a.htm">below 2.5 micrometers in diameter</a> are some of the most concerning pollutants out there: the smaller their size, the more likely they are to escape the lungs.</p><p>The new study doesn’t address whether black carbon enters the fetus itself. But ENVIR<i>ON</i>AGE’s protocol also includes sampling the umbilical cord, Bové says, and applying the same techniques to these tissues in the future could help solve that puzzle.</p><p>As ENVIR<i>ON</i>AGE continues, Bové says, many of the children born to participating mothers will return for regular health checkups, allowing the researchers to tie specific environmental exposures to health outcomes. Some of the oldest kids in the cohort are now around seven years old, she says, and the team is still recruiting. She and her colleagues also hope to better understand how exactly the particles damage both maternal and fetal tissues—processes that could involve everything from uncontrolled inflammation to alterations in how cells express different sets of genes.</p>
            <figure class="richtext-image full-width"><img alt="Untitled 2.jpg" class="richtext-image full-width" height="250" width="800"
            src="/wgbh/nova/media/images/Figure_S2.width-800.jpg"/><figcaption><p>Microscopy images of placental tissue from two different women exposed to relatively high levels of air pollution. Black carbon particles are black. Image Credit: Bové et al., Nature Communications, 2019</p><div class="credit"><p></p></div></figcaption>
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            <p>For now, simply seeing particles in the placenta “is very compelling,” Currie says. “There are some who will never be convinced by the statistics in an epidemiological study, but it’s pretty hard to explain how else these particles could have gotten there.”</p><p><a href="https://www.mailman.columbia.edu/people/our-faculty/jac2250">Joan Casey</a>, an environmental epidemiologist at Columbia University’s Mailman School of Public Health who was not involved in the study, agrees. “This is helping us connect the dots” between air pollution and poor health, she says. “If previous studies were linking A to Z, this starts to get at B, C, and D.”</p><p>In many countries, exposure to particulate matter is <a href="https://ourworldindata.org/air-pollution">declining</a>—but that’s not the case everywhere. Even in places where air pollution levels are relatively low, including the United States and Belgium (where the study took place), people are still feeling its ill effects, Gaskins says. What’s more, on scales both global and local, <a href="https://www.npr.org/sections/health-shots/2019/03/11/702348935/study-finds-racial-gap-between-who-causes-air-pollution-and-who-breathes-it">racial and ethnic minorities</a> and people of <a href="https://www.who.int/gho/phe/outdoor_air_pollution/en/">lower socioeconomic status</a> bear a disproportionate amount of the health burdens associated with these pollutants.</p><p>“This is more evidence that we need to continue working to clean up our air,” Casey says. After all, that may be the only way to make the health costs of pollution another toll that’s a thing of the past.</p></div>
  

  
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<p>A new study hints at the ways in which air pollution may directly impact a fetus.</p>

Soot from polluted air can reach the fetal side of the placenta





  
      <div class="rich-text"><p>Tom Yendell and Peter Longstaff are good at thinking on their feet. They have to be: Both were born without arms. But both still became painters, thanks to the extraordinary dexterity of their toes.</p><p>And that’s not all their feet can do. From an early age, both men have used their lower extremities to master everyday tasks typically performed with hands, including eating, writing, and typing—actions that appear to have prompted reorganizations in their brains.</p></div>
  

  
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      <div class="rich-text"><p>While non-disabled individuals typically have well-defined “hand maps” in their brains, with each finger holding dominion over a defined region, Yendell and Longstaff have “toe maps” that appear to be just as powerful and precise, according to new research. The <a href="https://www.cell.com/cell-reports/fulltext/S2211-1247(19)31061-7">study</a>, published today in the journal <i>Cell Reports,</i> showcases the flexibility of the human brain—potentially providing insights into how mind and body communicate across the spectrum of ability.</p><p>“Sometimes, having the unusual case—even the very rare one—might give you important insight into how things work,” neuroscientist Denis Schluppeck of the University of Nottingham in England, who was not involved in the study, <a href="https://www.sciencenews.org/article/artists-paint-feet-toe-maps-brain">told Laura Sanders at <i>Science News</i></a>.</p><p>Yendell and Longstaff are two of only three foot artists in the United Kingdom. Both were born to mothers who were treated during pregnancy with the drug thalidomide, which was later discovered to cause birth defects.</p><p>“These guys have spent their lives gaining expertise with using their feet,” study author Tamar Makin, a neuroscientist at University College London, <a href="https://www.nytimes.com/2019/09/10/science/brain-artist-thalidomide-feet-disability.html">told Francie Diep at <i>The New York Times</i></a>.</p></div>
  

  
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      <div class="rich-text"><p>Makin and her colleagues suspected that this unique developmental trajectory likely had lasting impacts on the brain, which possesses a sensory “map” of different body parts, allocating space proportionally to sensitivity (fingers and lips, for instance, usually occupy larger regions of the brain than areas like the back).</p><p>To spot discrepancies, the researchers performed brain scans on Yendell and Longstaff, along with nine volunteers who had arms and typical toe dexterity.</p><p>As expected, these latter nine individuals had a typical brain “footprint”: a solid region with no delineations representing individual toes. Yendell and Longstaff’s brains, however, were far more finely tuned, with clear-cut toe regions arranged in order. And when each of their toes was touched, the corresponding region of the brain lit up in an fMRI.</p><p>“We’re talking here about a whole map that doesn’t usually exist in adults,” Ella Striem-Amit, a neuroscientist at Georgetown University who was not involved in the study, told Diep.</p><p>Makin thinks that continued research in this area may someday aid training programs for individuals who don’t have full use of existing limbs, such as those with cerebral palsy, Diep reports. It’s also possible that the findings could help people who have suffered injuries as adults, like stroke victims, but that’s not a guarantee. Yendell and Longstaff both began training their feet at a very young age, and it’s likely there’s a limited window of time in which such drastic brain map rearrangements are possible—one that closes before adulthood, study author Daan Wesselink, also of University College London, <a href="https://www.eurekalert.org/pub_releases/2019-09/cp-tto090519.php">said in a statement</a>.</p><p>Yendell doesn’t consider his life to be any different from those of his non-disabled peers, Diep reports. The skills he’s acquired with his feet, he said, give him the same opportunities as people with arms. “How did you figure out how to do things with your hands?” he said. “You don’t need to be shown how to do it. You just do it naturally.”</p></div>
  

  
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<p>Two men born without arms showcase the brain’s extraordinary flexibility.</p>

Intricate ‘toe maps’ exist in the brains of artists who paint with their feet





  
      <div class="rich-text"><p>In the spring of 2015, Zika virus swept across the Americas and the Caribbean, infecting an estimated 800,000 people over the next year and a half. By the end of 2016, reports of the virus had dwindled down to almost nothing—and it seemed that the epidemic had finally begun to wane.</p><p>Blood, however, tells a different story. In truth, an outbreak was just beginning—one that may have affected tens of thousands of people in Cuba in 2017, according to <a href="https://www.cell.com/cell/fulltext/S0092-8674(19)30783-4">new research</a> published this week in the journal <i>Cell.</i></p><p>By analyzing viral RNA from the blood of infected travelers, an international team of scientists estimates that 5,707 cases of Zika went unreported in Cuba. Most of the infections occurred in 2017—many months after what the World Health Organization (WHO) declared to be a global public health emergency had ended<i>.</i> Because roughly 90 percent of outbreak infections go unconfirmed, the true number of infections could be about 10 times larger, <a href="https://www.nytimes.com/2019/08/22/science/cuba-zika-epidemic.html">reports Carl Zimmer for <i>The New York Times</i></a>.</p></div>
  

  
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      <div class="rich-text"><p>Zika is believed to have first appeared in the Americas <a href="https://www.who.int/emergencies/zika-virus/articles/one-year-outbreak/en/index2.html">in 2014</a>, when people began to fall ill in Brazil. It wasn’t until the following spring, however, that the mosquito-borne virus was identified by health officials. By then, Zika had spread into neighboring countries, leaving hundreds—and eventually thousands—of newborn infants of infected mothers with severe brain damage.</p><p>Containment efforts began on a global scale, and the number of reported cases declined. In November of 2016, WHO announced that the emergency was over. But researchers like Kristian Andersen, an infectious disease researcher at Scripps Research Translational Institute who had been monitoring the outbreak, were hesitant to hang up their hats.</p></div>
  

  
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      <div class="rich-text"><p>To keep tabs on lingering infections, Andersen and his colleagues thumbed through travel records from the Florida Department of Health and the European Centre for Disease Prevention and Control. They uncovered something startling: In 2017 and 2018, 155 travelers had returned to the United States or Europe with Zika in their blood. All but two had visited Cuba.</p><p>Based on the number of travelers who had gone to Cuba and returned with an infection, the researchers came up with a statistical model that predicted that the country’s “hidden” outbreak had likely been comparable in size to counts on other Caribbean islands.</p><p>None of this matched up with public records, which reflected little, if any, viral presence remaining in Cuba. To pinpoint the outbreak’s origin, the researchers sequenced Zika RNA from nine infected travelers and compared them to data from viruses collected from other parts of the Americas and the Caribbean. Their analysis revealed that the virus had likely arrived in Cuba multiple times from several different locations in the summer of 2016. Then, after a year of relative quietude, the Cuban outbreak peaked—a year after most other countries had endured the worst of the epidemic.</p><p>It’s not clear what was behind this delay, but it’s possible that Cuba’s aggressive campaign of pesticide spraying, targeting the <i>Aedes</i> mosquitoes that carry the virus, may have played a role. After global emergency status was lifted at the end of 2016, the eradication efforts ebbed—and Zika took the opening.</p><p>Even after epidemics emerge, they can be difficult to track, especially for viruses like Zika, which is difficult to diagnose, Ester Sabino, the director of the Institute of Tropical Medicine at the University of São Paulo in Brazil, who was not involved in the study, told Zimmer. Infected people often don’t feel symptoms, and those that do may mistake the mild fevers they get for other, more common illnesses. Zika also exits the body fairly rapidly, and tests can confuse it for the <a href="https://www.pbs.org/wgbh/nova/article/zika-dengue-exploit-mother-child/">closely related dengue virus</a>.</p><p>In other parts of the world, including Angola, Thailand, and India, Zika transmission is still a concern. It’s also unclear where else in the world the virus may continue to lurk unreported, due in part to a lack of diagnostic resources in many countries. But the researchers’ methods, including the monitoring of viral RNA, could help researchers home in on difficult-to-detect outbreaks, Jennifer Gardy, a genomic epidemiologist in the global health program at the Bill &amp; Melinda Gates Foundation who was not involved in the study, <a href="https://www.sciencemag.org/news/2019/08/infected-travelers-reveal-cuba-s-hidden-zika-outbreak">told Jon Cohen at <i>Science</i></a>.</p><p>The team’s technique, which intertwines travel data with genetic information, could also be applied to other infectious diseases, Andersen told Cohen. “This [work] sets up a framework for investigating infectious diseases more closely,” he said. “It’s a really important new tool to monitor infectious diseases around the world.”</p></div>
  

  
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<p>The virus simmered quietly in Cuba for about a year before infecting thousands.</p>

Researchers use viral genomes to uncover a Zika outbreak in Cuba





  
      <div class="rich-text"><p>Ebola may no longer be an incurable disease.</p><p>Two therapies tested in a clinical trial in the Democratic Republic of Congo appear to dramatically improve survival rates—so much so that both treatments will now be available to all enrolled patients, scientists announced today.</p><p>Both treatments rely on transferring antibodies that target the Ebola virus into patients, conferring swift protection. While Ebola typically carries a fatality rate of <a href="https://www.afro.who.int/health-topics/ebola-virus-disease">around 50 percent</a> (and, in the current outbreak, <a href="https://www.statnews.com/2019/08/12/for-the-first-time-clinical-trial-results-show-ebola-drugs-improve-survival-rates/">closer to 70 percent</a>), only about 10 percent of patients who began either therapy soon after falling ill succumbed to the disease.</p><p>Two other therapies in the trial, which began in November, with less impressive survival rates have been discontinued so that study participants can switch over to better options.</p></div>
  

  
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      <div class="rich-text"><p>The findings remain preliminary, and it’s unclear how the drugs will perform outside clinical trials. But the researchers behind the announcement are hopeful that this early success may pave the way to halting the ongoing epidemic in the Democratic Republic of Congo, which has killed nearly 2,000 since it <a href="https://www.cdc.gov/vhf/ebola/outbreaks/drc/2018-august.html">began last summer</a>.</p></div>
  

  
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      <div class="rich-text"><p>The treatments, called REGN-EB3 and mAb-114, both involve an injection of antibodies that latch onto the exterior of the Ebola virus. This swarming strategy blocks the virus from invading cells, while immune cells are recruited to take down the invader. A similar process underlies a third drug in the trial, ZMapp, which has until now been considered the standard of care in Ebola epidemics. But REGN-EB3 and mAb-114 both outperform their predecessor, as well as a fourth drug called remdesivir.</p><p>Across four treatment centers, half the patients taking ZMapp or remdesivir died, while REGN-EB3 and mAb-114 lowered the mortality rate to 29 and 34 percent, respectively. Deaths dwindled further for patients who received therapy soon after they began experiencing symptoms, with about 90 percent of REGN-EB3 and mAb-114 patients surviving, compared to around 65 to 75 percent of those taking the other drugs.</p><p>The results came as a complete shock, Sumathi Sivapalasingam, Regeneron’s medical lead on the REGN-EB3 project, <a href="https://www.statnews.com/2019/08/12/for-the-first-time-clinical-trial-results-show-ebola-drugs-improve-survival-rates/">told Helen Branswell at <i>STAT News</i></a>.</p><p>The trial’s findings also underscore the urgency for immediate treatment. On average, people arrive at treatment centers about four days after they fall ill, Michael Ryan from the World Health Organization <a href="https://www.theguardian.com/world/2019/aug/12/ebola-now-curable-after-trials-of-drugs-in-drc-say-scientists">told Sarah Bosely at <i>The Guardian</i></a>—a delay that not only reduces the chances of survival, but also increases the likelihood that the virus will be transmitted.</p><p>There’s no guarantee that the current numbers will hold as a new series of trials begin, now with a renewed focus on comparing the efficacy of REGN-EB3 and mAb-114. But the manufacturers of both drugs have already committed to continued production.</p>
            <figure class="richtext-image full-width"><img alt="6136_PHIL_scientists_PPE_Ebola_outbreak_1995.jpg" class="richtext-image full-width" height="521" width="800"
            src="/wgbh/nova/media/images/6136_PHIL_scientists_PPE_Ebola_outbreak_1995.width-800.jpg"/><figcaption><p>A photo from the 1995 Ebola outbreak in the Democratic Republic of Congo. Image Credit: CDC/ Ethleen Lloyd</p><div class="credit"><p></p></div></figcaption>
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            <p>It’s unclear why the two new treatments have a leg up over ZMapp, but it may have something to do with how each is formulated. While ZMapp is a slurry of a single antibody isolated from mice infected with Ebola, REGN-EB3 is a mixture of three—an immune cocktail that boosts the body’s chances of keeping the virus in check. mAb-114 also has a single antibody ingredient, but one isolated that was from a human Ebola survivor, <a href="https://www.wired.com/story/ebola-is-now-curable-heres-how-the-new-treatments-work/">reports Megan Molteni at <i>Wired</i></a>.</p><p>Having two options available also makes for an unexpected boon, providing a natural backup in case one drug or the other encounters complications, Ryan <a href="https://www.nytimes.com/2019/08/12/health/ebola-outbreak-cure.html">told Donald G. McNeil Jr. at <i>The New York Times</i></a>.</p><p>The forecast isn’t yet clear, especially for the now-unseated ZMapp. But potentially taking its place are two new therapies that may finally change the outcomes for Ebola patients.</p><p>“From now on, we will no longer say that Ebola is incurable,” Jean-Jacques Muyembe, the director general of the Institut National de Recherche Biomédicale in DRC, which oversaw the trial, told Bosely. “These advances will help save thousands of lives.”</p></div>
  

  
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<p>Both treatments rely on infusing patients with antibodies that latch onto the virus and block it from invading cells.</p>

Two new Ebola drugs dramatically boost survival in a clinical trial





  
      <div class="rich-text"><p>In case you haven’t gotten the memo, summer is <i>definitely</i> in full swing. That means peak season for ice cream, sunblock, and a regular deluge of pit-drenching, clothes-soaking, decorum-destroying sweat.</p><p>But before you scoff at this oft-maligned bodily fluid, consider this: Our signature brand of sweat is part of what makes us humans unique—and there’s more to the salty stuff than you might think. (And don’t forget that perspiration is, apparently, <a href="https://en.wikiquote.org/wiki/Thomas_Edison">99 percent of genius</a>.) So before you slather on that antiperspirant, chill out with some of the slick science behind nature’s OG thermostat.</p><p>I also promise to use the word “moist” no more than three times throughout the remainder of this article.</p></div>
  

  
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      <div class="rich-text"><h3><b>Sweat’s not gross. You’re gross.</b></h3><p>Let’s be real: Sweat isn’t glamorous. As <a href="https://www.mountsinai.org/profiles/angela-j-lamb">Angela Lamb</a>, a dermatologist at the Icahn School of Medicine at Mount Sinai, puts it, “sweat is kind of the urine of the skin.”</p><p>That doesn’t make perspiration useless. The primary function of this salty stuff, which is secreted by the 2 to 4 million sweat glands that stud our skin, is to keep the body from overheating. As sweat evaporates, it absorbs heat from the body, and what was once warm and moist (strike one) becomes relatively dry and cool.</p><p>All that vaporizing magic (er, science) happens thanks to the sweat produced by eccrine glands, which speckle most of the body, but are especially abundant on our palms and foot soles. Plenty of triggers can send eccrine glands into overdrive, including heat waves, intense exercise, and strong emotions like fear or anxiety. Spurred into action, the glands pump out a dilute mixture of water and a wee bit of salt.</p>
            <figure class="richtext-image full-width"><img alt="iStock-624673982.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/iStock-624673982.width-800.jpg"/><figcaption><p>In its purest form, sweat is actually odorless. But when the stuff from sweat glands—especially apocrine sweat glands—is processed by the bacteria living on your skin, things can get rank. Image Credit: Giulio Fornasar, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>While eccrine glands tend to hog the spotlight, there’s another culprit behind the body’s slick sheen: apocrine glands. These are mostly restricted to the armpits and the genital region, and secrete an oily, protein-rich version of sweat in times of stress or sexual excitement. (Fun fact: Mammary glands and the glands that produce earwax—more on that later—are modified apocrine glands.)</p><p>No matter where it hails from, though, sweat in its purest form is actually odorless, says <a href="https://www.massgeneral.org/doctors/doctor.aspx?id=18968">Sarina Elmariah</a>, a dermatologist at Massachusetts General Hospital. Until, that is, it hits the surface of skin. There, bacteria nosh on the unscented secretions—especially the rich, fatty apocrine formulation—and churn out that infamously gnarly stank as a byproduct.</p><h3><b>Why you won’t find a dog wiping its brow</b></h3><p>Humans aren’t the only animals that squeeze juice out of their bodies to keep cool—and there are actually a lot of mammals with sweat glands. But most of our furry brethren rely instead on the evaporative action of a surface that churns out liquid all the time: the moist (strike two) lining of the airway. That’s what dogs are doing when you see them panting, and it’s thought that the early ancestors of humans might have done it, too.</p><p>It’s not totally clear why humans swapped out panting for perspiring, or even if one tactic is necessarily superior to the other, says <a href="https://www.umass.edu/anthro/people/jason-kamilar">Jason Kamilar</a>, an anthropologist studying primate evolution at the University of Massachusetts Amherst. But the transition probably occurred when our ancestors migrated out of sheltered, humid rainforests into habitats with more sun exposure and drier air. Then, as early humans shed much of their body hair, rapid cooling via sweat likely became a boon during long daytime hunts, says <a href="https://www.med.upenn.edu/apps/faculty/index.php/g306/p1971822">Yana Kamberov</a>, a geneticist studying the evolution of sweat at the University of Pennsylvania.</p>
            <figure class="richtext-image full-width"><img alt="iStock-92045162.jpg" class="richtext-image full-width" height="534" width="800"
            src="/wgbh/nova/media/images/iStock-92045162.width-800.jpg"/><figcaption><p>You might pee like a racehorse, but you don&#x27;t exactly sweat like one. Most of the sweat glands on the equine body are apocrine. Image Credit: vesilvio, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>Other animals caught on to the perks of perspiration, too. It’s not uncommon to glimpse a horse drenched after a hard gallop (but that’s actually apocrine sweat glistening on their hides). Some mammals with soft paws, like cats and dogs, have eccrine glands in their foot pads, but that sweat is mostly for surface tension, which provides traction, Kamberov says. The <a href="http://blogs.bu.edu/bioaerial2012/2012/11/21/the-pygmy-glider/">feathertail glider</a> (<i>Acrobates pygmaeus</i>), a type of flying squirrel, actually pumps so much sweat out of its feet that it can scurry up <a href="https://www.nrcresearchpress.com/doi/10.1139/z98-212#.XTdaE2JKjOQ">vertical panes of glass</a>. </p><p>(You may have seen that hippopotamuses’ “sweat” is red. It’s true that they produce a rust-hued substance called <a href="https://www.nature.com/articles/429363a">blood sweat</a>, but technically, it’s neither blood nor sweat. Its function does overlap with perspiration proper, though, and also works as a sunscreen.)</p><h3><b>Don’t even try sweating the small stuff.</b></h3><p>Maybe you’re already a cool cat (with some super-steady foot pads) and you don’t need sweat to chill out. That’s fine—it’s good for other things, too: Sprinkled in with the salts in sweat is <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4583350/">a whole suite of proteins</a> with antimicrobial, or microbe-fighting, properties that may play a role in bolstering immunity.</p><p>But there are limits to perspiration’s power. The body can’t really “sweat out toxins,” for instance. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312275/">Heavy metals</a> and chemicals like <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255175/">bisphenol A</a> (BPA), which is found in plastics, can technically hitch a ride out of the body via the sweat glands, but they do so at concentrations too low to make much of a difference, Lamb says. Most of the body’s detoxifying power lies in the liver, gut, kidneys—and if you ingest a toxin, you’d be wise to choose a hospital over a steam room.</p>
            <figure class="richtext-image full-width"><img alt="47276410841_aae14e141b_o.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/47276410841_aae14e141b_o_hm7enmL.width-800.jpg"/><figcaption><p>A feathertail glider (Acrobates pygmaeus) in Queensland, Australia. Sweat glands on these flying squirrels&#x27; feet help them scale vertical structures. Image Credit: Dash Huang, flickr</p><div class="credit"><p></p></div></figcaption>
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            <p>Sweating also can’t replace a workout, and simply secreting stuff from these glands won’t be enough to “trick” a body into thinking it’s exercising. In spite of what some sauna operators might want you to think, perspiration doesn’t really confer any health benefits on its own, Lamb says.</p><h3><b>Sweaters: They’re not one-size-fits-all.</b></h3><p>Some people sweat more, others sweat less, and we only kind of understand why.</p><p>There’s probably at least some genetic component, Lamb says, because sweatiness often runs in families. In extreme cases, certain mutations can even lead to medical conditions in which people chronically sweat too much or too little.</p></div>
  

  
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      <div class="rich-text"><p>But the genetics of sweat isn’t all doom and gloom. A <a href="https://www.fasebj.org/doi/abs/10.1096/fj.09-129098?rfr_dat=cr_pub%3Dpubmed&amp;url_ver=Z39.88-2003&amp;rfr_id=ori%3Arid%3Acrossref.org&amp;journalCode=fasebj">delightful</a> <a href="https://www.nature.com/articles/ng1733">series</a> of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3674910/">studies</a> has <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2731057/">uncovered</a> a curious connection between earwax type and sweat odor. As it turns out, the same genetic mutation that causes people to make wet, sticky, brown earwax also bequeaths unto them hyperactive apocrine sweat glands—the more pungent perspirers (again, thanks to those pesky skin microbes). This mutation is particularly prevalent in populations with European ancestry, while those of East Asian descent are more likely to have dry, crumbly, grayish earwax and more apathetic apocrine glands.</p><p>Of course, your slick factor is also a product of certain lifestyle factors. Body size, for instance, appears to play a role, and weight gain may increase your propensity to perspire. The reason comes down to math: Higher mass decreases the body’s surface area to volume ratio, making it harder for internal heat to escape.</p><p>And as anyone who’s overindulged in spicy food can attest, sweat can reflect diet. Capsaicin—the kicky substance in chili peppers—tends to cue profuse perspiration. The things you nosh on can also change the <i>composition</i> of your sweat, resulting in distinct odors: Consider the savory funk of meat sweats, or the acrid tang that tends to follow a meal heavy in alliums like garlic or onions. Weirdest of all may be the herb fenugreek, which can imbue bodily secretions with the cloying aroma of maple syrup.</p><p>But when it comes to characterizing the sweat spectrum on a global scale, there are far more questions than answers. Kamilar and his student <a href="https://www.therunningprimate.com/">Andrew Best</a> are currently attempting to <a href="https://www.therunningprimate.com/sweat-glands-project">catalogue some of this diversity</a> by testing a decades-old theory that proposes that childhood conditions can dictate what percentage of an individual’s sweat glands stay active into adulthood—or retire young. One part of this idea is that people who spend their first two years of life in hot, dry conditions with limited access to artificial cooling might grow up sweatier than their peers whose parents kept the AC on high.</p><h3><b>One person’s skin urine is another person’s… beverage?</b></h3><p>So, no, we can’t use sweat as a replacement for sunscreen, or purge ourselves of toxins through our armpits. All the same, it seems the future of sweat is bright and shiny.</p><p>This brackish bodily fluid can already be used as a diagnostic for cystic fibrosis, a condition that affects how the body secretes mucus, sweat, and other substances. But researchers like <a href="https://www.ceas3.uc.edu/profiles/heikenjc">Jason Heikenfeld</a>, an electrical engineer at the University of Cincinnati, think perspiration can be used for much more.</p>
            <figure class="richtext-image full-width"><img alt="iStock-599117110.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/iStock-599117110.width-800.jpg"/><figcaption><p>A combination of genetic and lifestyle factors affect how much you sweat. Image Credit: tommaso79, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>It turns out eccrine sweat is a <a href="https://www.nature.com/articles/s41587-019-0040-3">surprisingly accurate and noninvasive diagnostic proxy</a> for blood, Heikenfeld says. The space just beneath the surface of our skin is chock full of vessels, and what’s secreted onto the surface of our skin tends to tug many of the chemicals present in blood along with it—including hormones and, potentially, certain types of drugs.</p><p>A system that analyzes the composition of sweat could prove useful for monitoring dehydration in athletes, or tracking levels of stress hormones in those suffering from chronic anxiety, Heikenfeld says. If sweat provides a comprehensive enough picture of a person’s health status, it may even someday play a role in helping doctors tailor treatments to individual patients.</p><p>Heikenfeld’s group isn’t the only one developing <a href="https://advances.sciencemag.org/content/5/1/eaav3294">sweat sensors</a>. Still other perspiration pioneers are looking into <a href="https://www.washingtonpost.com/news/speaking-of-science/wp/2014/08/13/these-temporary-tattoos-power-electronics-with-your-sweat/?utm_term=.ec6ec45766b2">powering small electronic devices</a> with sweat, while others have managed to laboriously <a href="https://www.bbc.com/news/technology-23360907">purify it into drinkable water</a> (though the latter effort was mostly intended to raise awareness about the <a href="https://www.who.int/news-room/fact-sheets/detail/drinking-water">780 million people worldwide</a> who lack access to clean drinking water).</p><p>One of the biggest barriers to all these applications, of course, is availability. Sweat production <i>can</i> be copious, but most people don’t secrete on command. Heikenfeld’s work is addressing this as well, and he and his team now have a way to stimulate small patches of skin to produce just enough sweat for a sensitive chemical analysis.</p><p>Stay moist (!), folks. You might just be cooler for it.</p></div>
  

  
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<p>Under extreme conditions, a human can produce more than three gallons of sweat in a single day.</p>

Cool down with the slick science of sweat





  
      <div class="rich-text"><p>There’s no two ways about it: From a young age, girls are <a href="https://psycnet.apa.org/doiLanding?doi=10.1037/a0021276">just as good at math</a> as boys. Even so, a <a href="https://www.nctm.org/Publications/Teaching-Children-Mathematics/Blog/Current-Research-on-Gender-Differences-in-Math/">gender gap</a> in math-focused fields persists, as women remain <a href="https://psycnet.apa.org/doiLanding?doi=10.1037%2Fa0027020">less likely</a> than men to pursue <a href="https://www.tandfonline.com/doi/abs/10.1080/00221546.2018.1486641?journalCode=uhej20">high-level studies</a> and careers in these areas.</p><p>Now, the findings of a <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1905779116">new analysis</a> might help explain a crucial piece of this longstanding discrepancy. According to a study published today in the journal <i>PNAS,</i> many girls who do every bit as well as their male peers in mathematics may still decide on more humanities-centric careers—because their verbal skills outshine their already high marks in math.</p><p>The research, which drew on data from more than 300,000 high school students from 64 countries around the world, emphasizes the key distinction between absolute and relative performance in math and reading. Around the globe, students of all genders are proficient in both subjects. But because they’re socialized to view mathematical and verbal aptitude as <a href="https://psycnet.apa.org/record/2004-11358-005">mutually exclusive</a>, many students might believe they must choose one or the other, despite being well equipped to pursue both areas of study.</p></div>
  

  
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      <div class="rich-text"><p>Because the paper examined data from only a single point in time, comparing students’ test scores to their future academic and career intentions, it can’t say anything definitive about cause and effect. Nonetheless, the authors argue that the girls’ comparative verbal advantage, measured by the difference between their scores in reading and math, could account for up to 80 percent of the gender gap in the inclination to go into math-related fields.</p><p>However, experts caution that the findings should <i>not</i> be interpreted as a reflection on innate differences in ability between the genders. It’s <a href="https://www.pnas.org/content/106/22/8801">well-established</a> that <a href="https://www.kellogg.northwestern.edu/faculty/sapienza/htm/science.pdf">social and cultural norms</a>, including the stereotypes and biases imposed on children from a very young age, account for a large part of the gender gap in the science, technology, engineering, and mathematics (STEM) fields. It’s likely that these norms are also the driving force behind this study’s results, the authors say, and social cues might still motivate young girls to prioritize verbal aptitude in a way that’s reflected in their high school performance.</p>
            <figure class="richtext-image full-width"><img alt="iStock-950614324.jpg" class="richtext-image full-width" height="531" width="800"
            src="/wgbh/nova/media/images/iStock-950614324.width-800.jpg"/><figcaption><p>Among different genders, there&#x27;s no inherent biological difference in math ability. But stereotypes and other social biases can make an enormous difference on who pursues math-related subjects professionally. Image Credit: Ridofranz, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>In the study, economists <a href="http://www.parisschoolofeconomics.com/breda-thomas/index_en.html">Thomas Breda</a> of the Paris School of Economics and <a href="https://sites.google.com/site/clotildenapp/home">Clotilde Napp</a> of Paris Dauphine University analyzed data from the <a href="https://www.oecd.org/pisa/data/">Programme of International Student Assessment (PISA)</a>, which conducts educational surveys in nearly 100 different countries every three years. All participating students were 15 years old—an age at which they were likely preparing to make major career decisions, Breda explains. The academic and professional intentions students report at this age tend to match up well with what they end up pursuing, he says.</p><p>Across the 64 countries analyzed in the study, students planning to pursue math-intensive studies and careers were more likely to identify as male than female, echoing trends that have been reported before. But while male students scored, on average, slightly higher in math than their female peers, the difference was small, and determines less than 10 percent of the observed gender gap in intentions.</p><p>In fact, almost none of the gap could be explained by how students were doing in relation to each <i>other</i>. Rather, it seemed to be more about how skills stacked up <i>within</i> each individual: While most girls excelled at reading over math, boys tended to show the opposite trend. Though there was no evidence to show that girls were doing poorly in math, their scores at age 15 seemed to reflect that they had a relative edge in the verbal department—one that had a big effect on their intentions for the future. And when the researchers adjusted for girls’ comparative verbal advantage in their data, the gender gap disappeared almost entirely.</p></div>
  

  
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      <div class="rich-text"><p>Part of this effect is probably attributable to the misconception that a student can be a math person or a verbal person, but not both, says <a href="https://www.awis.org/about-awis/staff/">Heather Metcalf</a>, Chief Research Officer at the Association for Women in Science, who was not involved in the study. Such a false binary could constrain the choices students make at a critical time in their education, she says.</p><p>What’s less clear, though, why girls score better in reading than math at age 15. Because the study didn’t track students over time, its results alone can’t definitively answer that question, Breda says. But he emphasizes that the study shouldn’t be misinterpreted as suggesting that women are inherently “worse” at math.</p><p>Years of research and <a href="https://journals.sagepub.com/doi/abs/10.1177/1529100614541236?rfr_dat=cr_pub%3Dpubmed&amp;url_ver=Z39.88-2003&amp;rfr_id=ori%3Arid%3Acrossref.org&amp;journalCode=psia">many</a> other <a href="https://www.pnas.org/content/106/22/8801">studies</a> have found <a href="https://pdfs.semanticscholar.org/98d3/dcfb67e27cca5c306ff7a09e8b3f14229f64.pdf">no evidence</a> for biology driving the <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2015.00530/full">gender gap</a> in math. Instead, it seems <a href="https://www.pnas.org/content/106/22/8801">social and cultural forces</a> are to blame—a theory backed up by the fact that the gender gap (as well as girls’ comparative verbal advantage, according to the new study) <a href="https://science.sciencemag.org/content/359/6381/1219.summary">differs</a> quite a bit <a href="https://www.kellogg.northwestern.edu/faculty/sapienza/htm/science.pdf">between</a> <a href="https://www.researchgate.net/publication/5338649_Diversity_Culture_gender_and_math">countries</a>.</p><p>“Society still feels like girls are not as smart, or should not be in math,” says <a href="https://peabody.vanderbilt.edu/bio/nicole-joseph">Nicole Joseph</a>, a mathematics education expert at Vanderbilt University who was not involved in the study.</p><p>This, along with a bevy of other biases, may be seeding the gender gap as early as <a href="https://journals.sagepub.com/doi/full/10.1177/2332858416673617">kindergarten</a>. Teachers, parents, and peers may inadvertently favor students who fit stereotypical gender roles. Girls <a href="https://psycnet.apa.org/record/2011-13792-002">internalizing messages</a> from mentors and media sources alike may subconsciously shy away from “unfeminine” fields of study, or underestimate or discount their own skill level in STEM, despite doing <a href="https://www.nature.com/articles/s41467-018-06292-0">just as well as boys</a>.</p><p>As schooling continues, the gap <a href="https://www.jstor.org/stable/10.5951/jresematheduc.44.4.0634?seq=1#page_scan_tab_contents">only grows</a>—and discrimination clearly persists at even the highest levels, Metcalf says. “Even when women go into math-related fields, there are pay inequities, and inequities as they advance into leadership positions.” In other words, there are plenty of hurdles—not just to entry into STEM fields, but to retention and advancement.</p><p>As such, addressing the underrepresentation of women in math-related fields is no simple task. Effecting change will require boosting girls’ confidence early in their education, exposing them to a wealth of career options and role models, and generally increasing the visibility of women in STEM. And much of the battle will come down to debunking existing stereotypes—about not only gender and other aspects of identity, but also <a href="https://www.frontiersin.org/articles/10.3389/fpsyg.2015.00189/full">math itself</a>.</p><p>For instance, women who are motivated to seek a career that will have a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3843492/">positive impact</a> on the world may also be socialized to view math-focused fields of study as incompatible with this goal, Metcalf says. Bridging the gender gap, then, could require both sparking enthusiasm for math at an early age and <a href="https://journals.sagepub.com/doi/abs/10.1177/1088868316642141">making students aware</a> of the <a href="http://andromeda.rutgers.edu/~powellab/docs/gcedm-cmesg/gutstein2003.pdf">societal benefits math-heavy careers can have</a>.</p>
            <figure class="richtext-image full-width"><img alt="iStock-1000887536.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/iStock-1000887536.width-800.jpg"/><figcaption><p>Closing the gender gap in math will require fighting stereotypes on both gender and the study of math itself. Image Credit: skynesher, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>There also won’t be a one-size-fits-all approach to this issue, which ultimately encompasses far more than gender, says <a href="https://www.dapperstats.com/">Juniper Simonis</a>, a quantitative ecologist at DAPPER Stats and <a href="https://500womenscientists.org/who-we-are">500 Women Scientists</a> leadership team member who was not involved in the study. While the current research is ambitious, they add, the global- and country-level analyses presented present an oversimplified account of the gender gap, which, despite its name, involves more than gender-based discrimination.</p><p>That’s due in part to how PISA collects data, focusing primarily on country-wide statistics, Breda says. But that limitation, Simonis says, makes it difficult to disentangle the relative contributions of other aspects of identity, like race, ethnicity, LGBTQ status, socioeconomic variables, and more—all of which will inevitably affect the barriers individuals face in school, the workplace, and beyond.</p><p>“The reality is that people aren’t just their gender,” Simonis says. “It’s important to acknowledge and incorporate information about other factors that also significantly impact and intersect with gender-based opportunities.” What’s more, though gender continues to be portrayed as binary in many contexts, it’s important to point out that it’s not, they add.</p><p>Joseph agrees, highlighting the fact that girls and women who are also underrepresented minorities are <a href="http://www.vctm.org/The-Invisibility-of-Black-Girls-in-Mathematics">especially marginalized in math-related fields</a>. While more women overall have earned math doctorates in the United States in recent years, most of this increase is due to the advancement of white women. The numbers of Black, Latinx, and Native American women in these cohorts, on the other hand, have barely budged.</p><p>Acknowledging intersectional identities in the gender gap will be key to designing effective interventions, Joseph says. Such an approach could end up being a boon for those hoping to tackle the stubborn gender gap in math.</p><p>“When policies and changes are made without understanding who they’re for, we end up missing the mark,” she says. “Maybe that’s why we’re not seeing the needle move.”</p></div>
  

  
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<p>Girls are great at math. But if they’re even better at reading, they might be more motivated to choose a humanities-focused career.</p>

Topic: Body & Brain

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