For millions of people, COVID-19 doesn’t end with a negative test. Weeks or months after traces of the virus disappear from noses and throats, symptoms can persist or come back. New ones might pop up and stick around for months. People suffering from long COVID are unwillingly in it for the long haul — and it’s still unclear who’s at the highest risk for the condition.
Researchers don’t yet have an official definition for long COVID, and its symptoms are wide-ranging (SN: 7/29/22). Some people struggle with extreme fatigue that interferes with their daily lives. Others can’t concentrate or struggle with memory amid thick brain fog. Still others have organ damage or a persistent cough and difficulty breathing. “There are a variety of different kinds of ways that people can have long COVID. It’s not just the one thing,” says Leora Horwitz, an internal medicine physician at New York University Langone Health. “That’s what makes it so hard to study.”
This spectrum of symptoms makes pinning down who’s at high risk for long-term health problems from the disease especially hard. Some post-COVID conditions may stem from virus-induced damage or from the stress of being hospitalized with severe disease. In other cases, the body’s own immune response to the virus could drive the damage. Or the virus may be hiding somewhere in the body, possibly the gut, helping symptoms to persist (SN: 11/24/20). Different causes may have different risk groups, says Hannah Davis, cofounder of the Patient-Led Research Collaborative, a research and advocacy group studying long COVID.
There are some broad hints about who’s at risk. Studies suggest that women are more likely than men to have lingering symptoms. COVID-19 patients with more than five symptoms in the first week of infection or preexisting health conditions such as asthma may be more likely to develop long COVID. Age also appears to be a risk factor, though results are mixed regarding whether the burden falls on older people or middle-aged people. Populations that were disproportionally hit by COVID-19 overall — including Black and Hispanic people — may similarly face disparities for long COVID. And while vaccination seems to protect people from developing long COVID, Horwitz says, it’s still unclear by how much.
Age is a risk factor for severe COVID-19, and the U.S. Centers for Disease Control and Prevention lists more than 30 health problems, including cancer and lung disease, that also raise the risk. “So many researchers assume that those [risk factors] will be the same for long COVID and there’s no scientific basis for that,” Davis says. There are many more that researchers could be missing when it comes to long COVID.
Using health records and exams, and knowledge of ailments with symptoms similar to long COVID, experts are on the hunt for those risk factors.
Examining health When it comes to getting a better handle on who’s at risk for long COVID — which also goes by the wonky alias Post-Acute Sequelae of SARS-CoV-2 infection — electronic health records may hold important clues.
Horwitz is part of the U.S. National Institutes of Health’s RECOVER initiative that aims to understand the long-term impacts of COVID-19. One arm of the study involves mining millions of electronic health records to find potential patterns.
Studying millions of these records should pinpoint potential risk factors that are rare in the population overall but perhaps more common for people with long COVID, Horwitz says. “That’s hard even in a cohort study of thousands.”
But health records aren’t perfect: They depend on physicians logging that patients are having trouble sleeping or focusing, or that they’re exhausted. “The things people are complaining about, we’re really bad at writing down those diagnoses on the record,” Horwitz says. “So we miss that.” To account for health records’ deficiencies, Horwitz and colleagues are also directly studying thousands of people. Participants answer a questionnaire every three months so that the team can identify what kinds of symptoms people have and whether they’re getting better or worse.
Then blood, urine, stool and saliva samples can reveal what’s happening in the body. Tests on those samples can uncover if the coronavirus is still around and causing trouble, or if the immune system has learned to attack the body itself. Participants with abnormal test results will undergo additional, targeted testing.
“Unlike electronic health records where it’s hit or miss, like somebody might have had a CAT scan or might not, here we say, ‘OK, you have trouble breathing. We will take a look at your lungs,’” Horwitz says.
The study includes a range of participants: adults and kids, pregnant people, those currently with COVID-19 and people who died after having the disease.
Some of the potential risk factors that the team is looking for include autoimmune diseases and other viral infections. The list may grow as more people join the study. “We’re trying to balance the fishing versus making sure that we’re at least fishing for things that could be in the water,” Horwitz says.
Among short supply, though, are people who never caught the virus — important “controls” to highlight what’s different about people who got COVID-19.
So far, more than 7,000 people have signed up, and the group plans to recruit around 10,000 more. It’s a lot of data, but early results may soon start coming in.
“We’ll probably try to do an interim peek at those data this fall,” Horwitz says. “It’s tricky because we deliberately wanted to enroll 18,000 people so we would have enough power to really look at the things we care about. I don’t want to cheat and look too early, but we also know that there’s a lot of interest.”
Striking similarities Some long COVID symptoms — brain fog, fatigue and trouble sleeping — mirror another illness: myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS. Other long COVID symptoms, such as rapid heartbeat and dizziness, fall in the category of nervous system disorders called dysautonomia. Similar symptoms could belie similar risk factors.
Yet potential risk factors for those conditions are largely missing from long COVID research, says Davis, who has had long COVID since March 2020. Among the possibilities that scientists are considering are things like Epstein-Barr virus, migraines and some autoimmune diseases.
Epstein-Barr virus could be a big one, Davis says. Infections last a lifetime because the virus can go into hiding in the body and possibly reemerge. That virus has been linked to ME/CFS for decades, though its role in the disease remains unclear, Davis says. Some early hints of a link between Epstein-Barr virus and long COVID already exist. Multiple studies have found evidence in blood samples from some long COVID patients that the immune system recently battled with Epstein-Barr virus, which can cause infectious mononucleosis, a disease characterized by extreme fatigue. Other studies have found signs of the virus itself. And in 2021, Davis and colleagues found that 40 out of 580 people with symptoms of long COVID who responded to an online survey reported having a current or recent Epstein-Barr virus infection.
With ME/CFS, it’s possible that another illness caused by a different virus triggers the Epstein-Barr virus, which then causes the fatigue syndrome. Given the parallels between that condition and long COVID, some scientists are wondering if the two are actually the same disease, with the coronavirus now known as one trigger.
Examining health conditions that raise the chances of long COVID could provide answers for both diseases, says Nancy Klimas, an immunologist at Nova Southeastern University in Fort Lauderdale, Fla. That’s in part because researchers can more easily identify people who developed lingering symptoms after a bout of COVID-19 compared with unknown infections that may precede ME/CFS.
Also, “there’s a huge difference in these two fields and it’s money,” Klimas says. She now has funding from the CDC to compare long COVID patients with people who have ME/CFS. The team hopes that physical exams and specialized tests will reveal whether the two diseases are indeed the same and be a step toward understanding the mechanisms behind the lingering symptoms.
Still, since long COVID as a whole encompasses such a wide range of symptoms, it will take time to uncover who is at risk of what.
If COVID-19 were just one disease impacting the lungs, heart or brain, the research might be easier, Horwitz says. “But we have to test everything.”
As Tanina Agosto went through her normal morning routine in July 2007, she realized something was wrong. The 29-year-old couldn’t control her left side, even her face. “Literally the top of my head to the bottom of my foot on the left side of my body could not feel anything.”
The next day, Agosto spoke with a doctor at the New York City hospital where she works as a medical secretary. He told her that she probably had a pinched nerve and to see a chiropractor.
But chiropractic care didn’t help. Months later, Agosto needed a cane to get around, and moving her left leg and arm required lots of concentration. She couldn’t work. Numbness and tingling made cooking and cleaning difficult. It felt a bit like looping a rubber band tightly around a finger until it loses sensation, Agosto says. Once the rubber band comes off, the finger tingles for a bit. But for her, the tingling wouldn’t stop.
Finally, she recalls, one chiropractor told her, “I’m not too big of a person to say there’s something very wrong with you, and I don’t know what it is. You need to see a neurologist.” In November 2008, tests confirmed that Agosto had multiple sclerosis. Her immune system was attacking her brain and spinal cord.
Agosto knew nothing about MS except that a friend of her mother’s had it. “At the time, I was like, there’s no way I’ve got this old lady’s condition,” she says. “To be hit with that and know that there’s no cure — that was just devastating.”
Why people develop the autoimmune disorder has been a long-standing question. Studies have pointed to certain gene variations and environmental factors. For decades, a common virus called Epstein-Barr virus has also been high on the list of culprits.
Now recent studies paint a clearer picture that Epstein-Barr virus instigates MS when the central nervous system gets caught in the cross hairs of an immune response to the virus’s attack. This recognition opens new options for treatment, or even vaccines. Perhaps therapies that target Epstein-Barr itself — or remove the cells in the body where the virus camps out — could jettison the virus before damage is done. Vaccines might one day “make multiple sclerosis become a historical disease like polio,” says Lawrence Steinman, a neurologist at Stanford University. “The trials will be arduous,” Steinman says. Still, “I think we might be able to put MS in the rearview mirror.”
For now, there’s a lot to learn, including how exactly the virus triggers MS, says Francesca Aloisi, a neuroscientist at the Italian National Institute of Health in Rome.
For many people with MS, even with current therapies, the disease can progress. Right now, Agosto’s symptoms are largely under control. Thanks to physical therapy, an anti-inflammatory diet and medication, she has about 90 percent function on the left side of her body. “Things like long-distance running are out of the question,” she says. Carrying grocery bags with her left arm is a challenge.
Studying the virus’s role in MS “will be an amazing game changer,” says Agosto, who is a patient advocate with the National Multiple Sclerosis Society’s New York City chapter. If Epstein-Barr virus is driving her disease, she wants to know: “How do we get this virus out of the driver’s seat?”
A familiar virus Multiple sclerosis is an uncommon disease, affecting nearly 3 million people globally. Yet Epstein-Barr virus is almost everywhere.
The virus, discovered in 1964, infects an estimated 90 percent of people around the world. People infected as young children might have a mild cold or show no symptoms. Teenagers or young adults may experience a bout of debilitating fatigue called infectious mononucleosis, or mono, that can last weeks or months.
These symptoms eventually fade. But Epstein-Barr infections hang on. The virus belongs to the herpesvirus family — a group known for instigating lifelong infections. The herpesviruses behind cold sores, genital herpes and chicken pox also stick around for life, usually staying quiet for long stretches. For example, varicella-zoster virus, which causes chicken pox, goes latent inside nerve cells but can resurface to cause the painful disease shingles (SN: 3/2/19, p. 22).
In the body, Epstein-Barr virus slips into the epithelial cells that line the surface of the throat, allowing the virus to spread to other people via saliva — hence mono’s nickname, “the kissing disease.” The virus also infects a type of immune cell called B cells, where it enters viral hibernation.
Epstein-Barr virus can cause problems long after the initial infection. People who had mono are more likely to develop cancers such as Hodgkin’s lymphoma than people who didn’t. And they are more likely to be diagnosed with MS. A teenage case of mono doesn’t mean long-term problems are inevitable. But avoiding mono-related fatigue doesn’t guarantee an escape from risk either. Agosto, for instance, doesn’t recall ever having mono. Establishing the link In March 2000, epidemiologist Alberto Ascherio of the Harvard T.H. Chan School of Public Health published research exploring the link between Epstein-Barr virus and MS. With colleague Mette Munch of the University of Aarhus in Denmark, Ascherio analyzed data from eight studies suggesting that MS patients are more likely to have had an Epstein-Barr infection than those without MS. Studies over the next 20 years continued to hint that the virus plays a role, but “the problem is to go from a suggestion or suspicion to proof,” says Ascherio. Getting that proof is difficult, because nearly everyone has been infected with Epstein-Barr virus, or EBV, yet very few have MS.
“If it’s true that EBV causes MS, then you would expect to find that those individuals who are not infected with EBV, they will not get MS,” Ascherio says. “It’s very simple.” He and colleagues needed to follow a large group of young adults who had never been infected.
The researchers found such a group in the U.S. military. Through the Department of Defense Serum Repository, the team had access to repeated blood samples from more than 10 million individuals, taken when active-duty members were screened for diseases such as HIV at the start of their service and then every two years. Using blood samples taken between 1993 and 2013, Ascherio and colleagues could identify people who had never been infected with Epstein-Barr virus, track new infections and learn when people who developed MS started showing symptoms.
Over that 20-year span, 801 people whose blood was tested were diagnosed with MS. Thirty-five of those people had no signs of Epstein-Barr virus infection in their first blood sample. But all but one became infected before their MS diagnosis. People infected with the virus were 32 times as likely to develop MS as uninfected people. What’s more, the researchers found that blood concentrations of a nervous system protein that is a signal of nerve damage rose after Epstein-Barr virus infection, before an MS diagnosis. The results prompted Ascherio and his team to make a bold claim in Science in January: “These findings cannot be explained by any known risk factor for MS and suggest EBV as the leading cause of MS.”
It is still possible that infection with Epstein-Barr virus is a time stamp for something else, perhaps not yet identified, that’s also relevant for MS, says Mark Allegretta, vice president of research at the National Multiple Sclerosis Society. “The way we talk about it now is that it’s very strong evidence that it’s necessary for development of MS, but it’s insufficient on its own.”
Ascherio isn’t deterred. “After 20 years of talking about EBV and MS, it’s quite exciting that we’ve finally nailed it down,” he says. “There was a lot of skepticism until now and that is fading away.” A skeptic convinced The fact that Epstein-Barr virus is implicated in so many diseases had many researchers skeptical of its link to MS, says Tobias Lanz, a neurologist at Stanford University. “It’s involved in tumors, it’s involved in MS, it’s involved in lupus, it’s in chronic fatigue syndrome. Somehow, people link it to everything and that makes us reasonably suspicious.”
Lanz’s mentor, Stanford rheumatologist William Robinson, was one of those skeptics. Once Lanz, Robinson and their colleagues found hints of how Epstein-Barr virus could spark nerve damage, however, Robinson became a believer.
The team discovered that immune proteins called antibodies from some MS patients attach to a key Epstein-Barr virus protein, as well as to a protein from the central nervous system. This finding, described in the March 10 Nature, suggests that as the immune system learns how to recognize the virus, it may also learn to attack nerve cells.
The viral protein, called EBNA1, helps Epstein-Barr virus persist in the body for life, hidden away inside B cells. Its molecular twin in the central nervous system, a portion of a protein called GlialCAM, is so similar that antibodies for the virus recognize and bind tightly to it too, the team found in lab experiments.
“That really changed everything,” Robinson says, calling it “an in-your-face result that you can’t dismiss as not being real.” In addition to adding to the evidence that Epstein-Barr virus causes MS, the finding also provides a hint of a possible mechanism: GlialCAM is found in glial cells, which support nerve cells and form the insulating layer myelin that helps nerve cells send signals (SN: 8/22/15, p. 18). Myelin is the very thing that is destroyed in MS.
About a quarter of patients in the study had antibodies that recognize both EBNA1 and GlialCAM. The similarities between the two proteins, called molecular mimicry, means that EBNA1 may not be a good viral protein to include in vaccines to curb diseases related to Epstein-Barr virus, says Steinman, the Stanford neurologist, who was also involved with the research. If the virus indeed sparks an autoimmune reaction, vaccines that target this viral protein or other mimics could harm myelin and spur MS. Viral damage Several studies support the idea that molecular mimicry causes MS damage. But other hypotheses are on the table.
Those B cells, for instance, where Epstein-Barr viruses hide out, produce antibodies. One possibility is that B cells infected with Epstein-Barr virus transform in ways that encourage the immune system to attack the body’s own tissues.
Aloisi, the neuroscientist in Rome, backs a different hypothesis: Perhaps the immune system’s attack on the virus itself is behind the damage.
“The biology of the virus is so similar to the biology of the disease,” Aloisi says. For some people, MS can go through phases of silence where the disease is stable, no better, no worse. The disease then reactivates, producing new brain lesions and worsening symptoms. Epstein-Barr virus can similarly come out of latency, perhaps causing a surge of problems before returning to hibernation inside host cells.
In 2007, Aloisi and colleagues discovered unexpected clusters of B cells within the membranes that cover and protect the brain. In all but one of 22 patients studied, some of those B cells were infected with Epstein-Barr virus.
The finding “was like a bomb in the field,” Aloisi says, “because nobody ever thought about this possibility.” Other researchers initially failed to replicate the results. But “little by little other work came out [in support],” she says. “It’s difficult to find these [clusters of B cells] in the brain because people with MS don’t have large, inflamed brains. It’s small spots here and there.”
It’s possible that the central nervous system becomes a stronghold for the virus, Aloisi says. Immune cells called T cells, which can either coordinate an attack or kill infected cells, rush in. Some virus-infected B cells die, but the immune system can’t eliminate the virus. Myelin gets caught in the cross fire. “This creates a situation that is extremely detrimental to the tissue,” she says. Treatment tactics Regardless of whether Epstein-Barr virus drives MS symptoms directly or causes the body’s immune response to go haywire, the big question is what to do about it.
One obvious path is to develop MS drugs that go after the virus, Aloisi says. Some drugs that block hepatitis B virus and HIV have shown potential against Epstein-Barr virus in lab-grown cells, says Ascherio, the Harvard epidemiologist. But those results are very preliminary.
Another option is to go after the infected cells. A few MS therapies may do that already. The existing MS therapy natalizumab already prevents B and T cells from crossing into the central nervous system. Fingolimod may do that as well. Another drug called ocrelizumab, approved for patients with MS in 2017, is an antibody that attaches to a protein on B cells and triggers cell death. The drug helps patients, like Agosto, who have relapsing-remitting MS, but it’s less effective for people with a progressive form of the disease, who have fewer treatment options (SN: 12/9/17, p. 20).
Researchers thought the drug dampened faulty immune responses by depleting B cells, Lanz says. “But it could also well be that we’re hitting those particular pathogenic B cells that are infected with Epstein-Barr virus. So the B cell depletion might actually be an anti-EBV drug and nobody appreciated that.”
Aloisi agrees. “Now we need something that targets the EBV-infected cells, not all of the B cells,” she says. Indiscriminately killing B cells puts patients at risk for other infections. One way to get around that could come in the form of T cell therapies that go after only infected cells. Such therapies are already in clinical trials in MS patients.
Some researchers suspect that antiviral treatments would probably make the most sense when used early on, before the immune system eats away at the myelin around the nerve cells. Once the virus has kick-started an immune response to attack the nervous system, “the train may already be out of the station,” says neuroimmunologist Emily Harrington of Ohio State University’s Wexner Medical Center in Columbus.
A vaccine Even better than stopping the infection once it starts would be to build defenses before the virus invades, or to stop it from reawakening. Enter vaccines.
The widespread impact of mono and Epstein-Barr virus’s links to cancer and autoimmune disease had already spurred vaccine research, so a few potential shots are already in the pipeline. But Epstein-Barr virus has a complex way of invading the body, says vaccinologist Javier Gordon Ogembo of City of Hope, a cancer care center in Duarte, Calif. The virus uses at least five viral proteins to invade both epithelial cells and B cells. A vaccine would need to drive an immune response that blocks the virus’s entry into both cell types to prevent infection. “This is the reason, I think, why there has not been a vaccine so far,” Ogembo says. Pharmaceutical company GlaxoSmithKline took one vaccine candidate to clinical trials in the early 2000s. It seemed to stop people from developing mono, but it didn’t meet the original goal of preventing infection overall. So the company abandoned the vaccine.
Moderna, the biotechnology company made famous for its effective COVID-19 vaccine, recently launched a clinical trial of an mRNA vaccine for Epstein-Barr virus. The shot teaches the body to recognize four of the five viral proteins that help the virus invade both cell types, says viral immunologist Katherine Luzuriaga of the University of Massachusetts Chan Medical School in Worcester, who is involved in the trial. For now, the team is testing whether the vaccine sparks a strong immune response and getting a sense for whether it might curb cases of mono.
In March, the U.S National Institutes of Health launched a clinical trial to test a vaccine that uses nanoparticles to teach the body to recognize the virus and get rid of it. Ogembo and colleagues at City of Hope are developing another vaccine that uses a modified virus as the immune system’s instructor.
Although clinical trials could reveal within the next few years whether the vaccines can control mono, it will be decades before researchers learn anything about the potential impact on cancer or MS, Luzuriaga and Ogembo say. The hope is to see an outcome like the vaccines for human papillomaviruses, Luzuriaga says, which reduce the number of HPV infections and led to a dramatic reduction in cervical cancers.
Developing therapeutic vaccines for people who already have MS may also be possible, Ascherio says. The aim would be to stop the virus from emerging from its slumber inside B cells. It would be akin to the shingles vaccine, which prevents the painful reactivation of varicella-zoster virus in nerve cells.
That is Steinman’s aim as well, but he envisions a shot that would put a check on the undesirable immune response. Steinman and colleagues have tested such a vaccine to try and teach MS patients’ immune systems to ignore and not harm a protein called myelin basic protein, which helps add myelin to nerves. There were hints the vaccine might have been effective, but the team ultimately stopped the project.
“If it weren’t for other very powerful therapies becoming approved in that same time frame, we may have continued,” Steinman says. Now, he wants to make a vaccine that helps MS patients tolerate, rather than attack, the central nervous system protein GlialCAM.
Researchers at BioNTech, also famous for developing a COVID-19 vaccine, are working on something similar. In mice with a disease close to MS, the company showed that an mRNA vaccine could keep the immune system from attacking myelin proteins, the team reported in January 2021 in Science.
Time will tell how effective any of these shots might be. But with studies providing more and more evidence that Epstein-Barr virus is linked to many diseases, Ogembo says, “it’s time to make a vaccine and get rid of it.”
The Arctic is heating up at a breakneck speed compared with the rest of Earth. And new analyses show that the region is warming even faster than scientists thought. Over the last four decades, the average Arctic temperature increased nearly four times as fast as the global average, researchers report August 11 in Communications Earth & Environment.
And that’s just on average. Some parts of the Arctic Ocean, such as the Barents Sea between Russia and Norway’s Svalbard archipelago, are warming as much as seven times as fast, meteorologist Mika Rantanen of the Finnish Meteorological Institute in Helsinki and colleagues found. Previous studies have tended to say that the Arctic’s average temperature is increasing two to three times as fast as elsewhere, as humans continue causing the climate to change. To calculate the true pace of the accelerated warming, a phenomenon called Arctic amplification, the researchers analyzed observational data from 1979 to 2021 (SN: 7/1/20). Globally, the average temperature increase over that time was about 0.2 degrees Celsius per decade. But the Arctic was warming by about 0.75 degrees C per decade. Even the best climate models are not doing a great job of reproducing that warming, Rantanen and colleagues say. The inability of the models to realistically simulate past Arctic amplification calls into question how well the models can project future changes there.
It’s not clear where the problem lies. One issue may be that the models are struggling with correctly simulating the sensitivity of Arctic temperatures to the loss of sea ice. Vanishing snow and ice, particularly sea ice, are one big reason why Arctic warming is on hyperspeed. The bright white snow and ice create a reflective shield that bounces incoming radiation from the sun back into space. But open ocean waters or bare rocks absorb that heat, raising the temperature.
A crying baby, a screaming adult, a teenager whose voice cracks — people could have sounded this shrill all the time, a new study suggests, if not for a crucial step in human evolution.
It’s what we’re missing that makes the difference. Humans have vocal cords, muscles in our larynx, or voice box, that vibrate to produce sound (SN: 11/18/15). But unlike all other studied primates, humans don’t have small bits of tissue above the vocal cords called vocal membranes. That uniquely human trait helps people control their voices well enough to produce the sounds that are the building blocks of spoken language, researchers report in the Aug. 12 Science.
Vocal membranes act like a reed in a clarinet, making it easier for some animals to shout loud and shrill. Think of the piercing calls of howler monkeys (SN: 10/22/15). When researchers used MRI and CT scans to look for vocal membranes in 43 different primate species, the scientists were surprised by what they saw: All primates except humans had the tissue.
That loss of vocal membranes would have been a “very major, very revolutionary event in human evolution,” says Takeshi Nishimura, a paleontologist at Kyoto University in Japan.
Primates mostly make sound in the same basic way: They push air out from their lungs while vibrating muscles in the larynx to create sound waves. To understand the role that vocal membranes play, Nishimura’s team studied videos of primate voice boxes in action in chimpanzees, rhesus macaques and squirrel monkeys. The researchers also took larynges from macaques and chimpanzees that had died of natural causes and — in what’s common practice for the field — mounted the parts on tubes, pushing air through the larynges to see how the vocal cords and membranes would react.
In both experiments, the larynges made sounds that would often fluctuate wildly in pitch. Nishimura’s team found that happens only when an animal has both vocal membranes and vocal cords. In humans, that sort of screeching can happen when we put extreme amounts of pressure on our voice, like when we scream — or when teens struggle with controlling their growing vocal cords and their voices crack. But those are rare cases. Since humans don’t have vocal membranes, we usually make more stable sounds than other primates, the team concludes. Our mouths and tongues, the idea goes, can then manipulate those stable tones into the complex sounds that language is based on.
“That’s a really elegant explanation,” says Sue Anne Zollinger, an animal physiologist at Manchester Metropolitan University in England who was not involved in the study. It’s almost counterintuitive, she says: “You lose complexity to be able to produce more complex sounds.”
The loss of vocal membranes isn’t the only thing that makes humans more eloquent than other primates. Beyond anatomical differences, humans have specific genes that may have helped drive language evolution (SN: 8/3/18). And perhaps most importantly, human brains are structured differently from other primates in ways that also give us more control over our speech (SN: 12/19/16).
The one-of-a-kind pattern of ridges and valleys in a fingerprint may not only betray who was present at a crime scene. It may also tattle about what outlawed drugs a suspect handled.
With advanced spectroscopy, researchers can detect and measure tiny flecks of cocaine, methamphetamine and heroin — in some cases as little as trillionths of a gram — on a lone fingerprint. The study, led by researchers at the National Institute of Standards and Technology in Gaithersburg, Md., appears May 7 in Analytical Chemistry. Using an ink-jet–printed array of known quantities of drugs, researchers calibrated their spectroscopy techniques to measure specks of the chemicals. Then, using a 3-D printed plastic finger and a synthetic version of finger oil, researchers created drug-tainted fingerprints pressed onto paper or silicon.
On paper, the researchers detected as little as 1 nanogram of cocaine and amounts above 50 nanograms of methamphetamine and heroin. On silicon, the method picked up as little as 8 picograms of cocaine and heroin and around 1 nanogram of methamphetamine.
Researchers could also point to the location of the drugs on the fingerprint— at the peaks or dips of the pattern, for instance. Such information, the authors say, could help investigators finger what chemicals a suspect handled first and help corroborate a timeline of events in a crime.
In the animal world, just like the human one, sometimes it’s not easy being mom. Fellow blogger Laura Sanders will tell you all about the trials and tribulations of being a mother to Homo sapiens. But some moms of the animal kingdom make sacrifices that go far beyond carrying a baby for nine months or paying for college.
Binge-eating sea otters Adult female sea otters spend six months out of every year nursing at least one pup, sometimes two. Feeding herself isn’t easy — she’s got to eat the equivalent of 20 to 25 percent of her body mass every day to survive. But that amount has to increase while she’s nursing. By the time a pup is weaned at six months old, mom has to nearly double her food intake, researchers reported last year in the Journal of Experimental Biology. And to make matters worse, sometimes her kid will steal her food. Single, starving mom About two months before giving birth, a polar bear will enter her maternity den, remaining there for four to eight months. She stays holed up for that entire time, never eating, never drinking. Her cubs, only about half a kilogram at birth, grow quickly feeding on mom’s rich milk. And once they’re big enough to venture out, mama bear leads her babies straight to the sea so she can finally catch herself a meal.
Walled in by poo Various species of Asian hornbills all share a similar nesting strategy: To protect her eggs from predators, mom walls herself up in a tree with a combination of mud, feces and regurgitated fruit. She leaves one tiny hole, through which dad feeds her for up to four months when mother and children are finally ready to emerge.
Endless sleepless nights Human babies are known for their ability to rouse mom with their cries and prevent her from getting much sleep. But orca and dolphin moms don’t sleep at all for a month or more after they give birth. Unlike human babies that need a lot of sleep, tiny orcas and dolphins don’t sleep in the weeks after they’re born. That means no sleep for mom.
It’s mom for dinner There’s a hint in the name of a limbless amphibian called Microcaecilia dermatophaga — young caecilians eat the skin of their mother, researchers reported in 2013 in PLOS ONE. But in a recent issue of Science News, Susan Milius highlighted an even more disgusting case of mom serving herself up for her kids: A female Stegodyphus lineatus spider feeds her young on a regurgitated slurry made up of the last meals she’ll ever eat — and her own guts. Milius writes:
“As liquid wells out on mom’s face, spiderlings jostle for position, swarming over her head like a face mask of caramel-colored beads. This will be her sole brood of hatchlings, and she regurgitates 41 percent of her body mass to feed her spiderlings.”
The next time your mom talks about how much she sacrificed for you, say thanks, but remember, at least you didn’t eat her stomach.
Mother’s Day is on my mind, and I’ve been thinking about the ways I’m connected to my mom and my two little daughters. Every so often I see flickers of my mom in my girls — they share the lines around their smiles and a mutual adoration of wildflowers. Of course, I’m biased. I know that I’m seeing what I’m looking for. But biologically speaking, mothers and their children are connected in a way that may surprise you.
Way back when you and your mom shared a body, your cells mingled. Her cells slipped into your body and your cells circled back into her. This process, called fetal-maternal microchimerism, turns both mother and child into chimeras harboring little pieces of each other.
Cells from my daughters are knitted into my body and bones and brain. I also carry cells from my mom, and quite possibly from my grandma. I may even harbor cells from my older brother, who may have given some cells to my mom, who then gave them to me. It means my younger brother just might have cells from all of us, poor guy. This boundary blurring invites some serious existential wonder, not least of which might involve you wondering if this means your family members really are in your head.
These cellular threads tie families together in ways that scientists are just starting to discover. Here are a few of my favorite instances of how cells from a child have woven themselves into a mother’s body: Fetal cells are probably sprinkled throughout a mother’s brain. A study of women who had died in their 70s found that over half of the women had male DNA (a snippet from the Y chromosome) in their brains, presumably from when their sons were in the womb. Scientists often look for male DNA in women because it’s easier than distinguishing a daughter’s DNA from her mother’s. If DNA from daughters were included, the number of women with children’s cells in their brains would probably be even higher.
When the heart is injured, fetal cells seem to flock to the site of injury and turn into several different types of specialized heart cells. Some of these cells may even start beating, a mouse study found. So technically, those icky-sweet Mother’s Day cards may be right: A mother really does hold her children in her heart.
Fetal cells circulate in a mother’s blood. Male DNA turned up in blood samples from women who were potential stem cell donors. That result may have implications for stem cell transplants. This cell swapping may make parents better donor candidates for their children than strangers, for instance. Other studies have found fetal cells in a mother’s bones, liver, lungs and other organs, suggesting that these cells have made homes for themselves throughout a mother’s body. Maybe this is a way for a child to give back to the mother, in a sense. Growing fetuses slurp nutrients and energy out of a mother’s body during pregnancy (not to mention the morning sickness, heartburn and body aches). In return, fetuses offer up these young, potentially helpful cells. Perhaps these fetal cells, which may possess the ability to turn into lots of different kinds of cells, can help repair a damaged heart, liver or thyroid, as some studies have hinted.
Before I get carried away, a caveat: these cells may also make mischief. They may have a role in autoimmune disorders, for instance.
Microchimerism also has implications here for women who have lost pregnancies, an extremely common situation hidden by the taboo of talking about miscarriages. Fetal cells seem to migrate early in pregnancy, meaning that even brief pregnancies may leave a cellular mark on a woman.
Scientists are just starting to discover how this cellular heritage works, and how it might influence health. The scientist in me can’t wait to see how this story unfolds. But for now, I’m content to marvel at the mother and daughters in me.
A zap to the head can stretch the time between intention and action, a new study finds. The results help illuminate how intentions arise in the brain.
The study, published in the May 6 Journal of Neuroscience, “provides fascinating new clues” about the process of internal decision making, says neuroscientist Gabriel Kreiman of Harvard University. These sorts of studies are bringing scientists closer to “probing some of the fundamental questions about who we are and why we do what we do,” he says. Figuring out how the brain generates a sense of control may also have implications for people who lack those feelings. People with alien hand syndrome, psychogenic movement disorders and schizophrenia can experience a troubling disconnect between intention and action, says study coauthor Biyu Jade He of the National Institutes of Health in Bethesda, Md.
In the study, the researchers manipulated people’s intentions without changing their actions. The researchers told participants to click a mouse whenever the urge struck. Participants estimated when their intention to click first arose by monitoring a dot’s position on a clockface.
Intention to click usually preceded the action by 188 milliseconds on average, the team found. But a session of transcranial direct current stimulation, or tDCS, moved the realization of intention even earlier, stretching time out between awareness of intention and the action. tDCS electrodes delivered a mild electrical zap to participants’ heads, dialing up the activity of carefully targeted nerve cells. After stimulation, intentions arrived about 60 to 70 milliseconds sooner than usual. tDCS seemed to change certain kinds of brain activity that may have influenced the time shift, EEG recordings suggested.
The results highlight how thoughts and intentions can be separated from the action itself, a situation that appears to raise thorny questions about free will. But these tDCS zaps didn’t change the action outcome or participants’ feelings of control, only the reported timing of a person’s conscious intention.
MONTREAL — For the first time, scientists have precisely captured a map of the boisterous bang radiating from a lightning strike. The work could reveal the energies involved in powering some of nature’s flashiest light shows.
As electric current rapidly flows from a negatively charged cloud to the ground below, the lightning rapidly heats and expands the surrounding air, generating sonic shock waves. While scientists have a basic understanding of thunder’s origins, they lack a detailed picture of the physics powering the crashes and rumbles. Heliophysicist Maher Dayeh of the Southwest Research Institute in San Antonio and colleagues sparked their own lightning by firing a long, Kevlar-coated copper wire into an electrically charged cloud using a small rocket. The resulting lightning followed the conductive wire to the ground. Using 15 sensitive microphones laid out 95 meters from the strike zone, Dayeh said he and his colleagues precisely recorded the incoming sound waves. Because sound waves from higher elevations took longer to reach the microphones, the scientists could create an acoustic map of the lightning strike with “surprising detail,” Dayeh said. He presented the results May 5 at a meeting of the American Geophysical Union and other organizations.
The loudness of a thunderclap depends on the peak electric current flowing through the lightning, the researchers found. This discovery could one day allow scientists to use thunder to sound out the amount of energy powering a lightning strike, Dayeh said. SHOCK AND AWE Scientists shot a long copper wire into a lightning-prone cloud using a small rocket. The generated lightning followed the wire down to the ground, allowing the researchers to record the sound waves of the resulting thunder. The green flashes are caused by the intense heating of the copper wire. Credit: Univ. of Florida, Florida Institute of Technology, SRI
A new high-tech glove totally sucks — and that’s a good thing.
Each fingertip is outfitted with a sucker inspired by those on octopus arms. These suckers allow people to grab slippery, underwater objects without squeezing too tightly, researchers report July 13 in Science Advances.
“Being able to grasp things underwater could be good for search and rescue, it could be good for archaeology, [and] could be good for marine biology,” says mechanical engineer Michael Bartlett of Virginia Tech in Blacksburg. Each sucker on the glove is a raspberry-sized rubber cone capped with a thin, stretchy rubber sheet. Vacuuming the air out of a sucker pulls its cap into a concave shape that sticks to surfaces like a suction cup. Pumping air back into the sucker inflates its cap, causing it to pop off surfaces. Each finger is also equipped with a Tic Tac–sized sensor that detects nearby surfaces. When the sensor comes within some preset distance of any object, it switches the sucker on that finger to sticky mode.
Bartlett and colleagues used the glove to pick up objects underwater, including a toy car, plastic spoon and metal bowl. Each sucker could lift about one kilogram in open air — and could lift more underwater, with the help of buoyancy, Bartlett says. Adding more suckers could give the glove an even stronger grip. The octopus-inspired glove barely brushes the surface of what octopuses and other cephalopods can do. Octopuses can individually control thousands of suckers across their eight arms to feel around the seafloor and snatch prey. The suckers do this using not only tactile sensors, but also chemical-detecting cells that “taste” their surroundings (SN: 10/29/20).
The new glove is far from turning fingers into extra tongues. But Bartlett is intrigued by the possibility of adding chemical sensors so that the suckers stick to only certain materials.
