If whole organs could be frozen and stored … surgeons would be able to perform far more transplants…. For all their efforts, though, cryobiologists (biologists who study the effects of cold on life) have not been very successful with organ freezing…. Nobody to date has cooled whole mammalian hearts any lower [than −20° Celsius] or longer [than six hours] and revived them.
Update Scientists still struggle to keep donor hearts on ice for longer than six hours, but it is now possible to store a different organ — the liver — at below-freezing temperatures for more than a day. The challenge has been figuring out how to stop ice from crystallizing and damaging cells. In 2019, scientists reported successfully warming up several human livers after supercooling them for 27 hours (SN: 10/12/19 & 10/26/19, p. 10). This and other preservation methods such as freezing at high pressures or thawing using nanoparticles aren’t yet ready for the operating room, but they have the potential to keep thousands of lifesaving organs from going to waste each year.
Potential hints of weird new particles in a dark matter detector have evaporated with new data.
Following up on a beguiling result from its predecessor experiment, the XENONnT experiment found no sign of extra blips that could point to new particles or another phenomenon, scientists report July 22 in Vienna at the International Conference on Identification of Dark Matter.
The XENONnT experiment (pronounced “xenon n ton”), at the Gran Sasso National Laboratory in Italy, uses 5.9 metric tons of liquid xenon to search for dark matter, an elusive substance that so far has been seen only via its gravitational effects in the cosmos (SN: 10/25/16). The detector is designed to look for dark matter particles crashing into xenon atoms’ nuclei, causing them to recoil. But the detector can also spot recoiling electrons. In 2020, a smaller version of the experiment, called XENON1T, reported greater-than-expected numbers of those ricocheting electrons (SN: 6/17/20). “This caused a lot of stir when we published it,” says physicist Rafael Lang of Purdue University in West Lafayette, Ind.
That surplus, some scientists suggested, could have been explained by some unexpected new physics, such as hypothetical lightweight particles that may originate from the sun called solar axions. But the excess wasn’t large enough to be convincing, so more data were needed.
In the new analysis, which uses about 97 days of data, XENONnT spotted as many electron recoils as expected due to known particle interactions, the researchers also reported in a paper posted on the experiment’s website. Scientists don’t know what caused the extra detections in the previous experiment, but it’s possible it was merely a statistical fluke, Lang says. Or it may have been due to small amounts of tritium — hydrogen atoms with two neutrons in their nuclei — in the detector.
With the red herring out of the way, XENONnT researchers are now combing through their data for nuclear recoils, in hopes of detecting the real deal.
How descendants of cannibals evolved abilities to share a home mostly without killing each other — never mind the rare oopsie snack — resonates after several pandemic years.
Among the many kinds of velvety Delena huntsman spiders, four species from Australia show what for their kind is a downright freaky tolerance between a mom and her live-in offspring. “Cannibalism might happen occasionally, but with Delena cancerides, it’s almost never,” says behavioral ecologist Linda Rayor of Cornell University, who has studied them in the wild and in her lab for 20 years. Not eating their own kind isn’t really the oddity here: Cannibalism varies a lot among spider species, Rayor says, but overall, it’s mostly a move of solitary kinds of spiders if they meet outside of flirting or baby-guarding demands (SN: 4/25/22).
A small number of Delena species, however, generally tolerate their own kind. The only exception Rayor sees in D. cancerides are a wild-caught female’s takedown of a full-grown male still in her cage after she lays eggs. “Wild-caught females are very intolerant of males who stick around too long,” she says.
What’s really strange, at least in the arachnid world, is these spiders’ shared family life. Out of the more than 50,000-plus known spider species, biologists classify fewer than 80 as truly social. In the most complex, hundreds or even thousands of females spin a great airy silken city, where some stay their entire lives. However, Rayor says, “my huntsman don’t do that.”
Some other biologists wouldn’t consider the Delena spiders Rayor studies as fully social — no spun-silk Sydney. Yet these spiders are not truly solitary either. A female doesn’t spin a web but shelters in a crevice, perhaps behind peeling bark on an acacia tree or under a slab of rock. These crevice-dwellers’ bodies look unusually flattened in profile: “a credit-card spider,” one scientist called the species, with some poetic license.
When a female triumphs in finding real estate, the kids can linger for months in her splendid mom cave — the kids with no sex life yet, that is. Never mind that older offspring already go out hunting on their own at night, or that often one or two later clutches of little ones hatch before the older ones leave. Spider moms guarding poppyseed-tiny hatchlings are common. Living with capable, nearly grown offspring, is strange in the arachnid world. The most sociable of these sort-of tolerant moms, D. cancerides, lets a cohort of youngsters hang around the home for about a year after hatching. That’s a good portion of life for spiders that live only two and a half years. One of the reasons for doing so may sound familiar: Suitable housing can be hard to find.
Rayor once thought hanging with mom was an Australian thing, but she has now learned about tolerant moms from Madagascar in a Damastes species. To study the evolution of traits that add up to family life in the five species, Jacob Gorneau, now at the California Academy of Sciences in San Francisco, and his Cornell colleagues used four genes from spiders in 37 huntsman genera to create the most ambitious genealogical tree yet of the family. Then Rayor turned to her decades of data to see what behaviors appeared on branches leading to lingering kids.
For instance, a form of egg sac called “plastered” — not drunk but spun like a firmly anchored splat on a surface of spider retreats — shows up in branches with the family-tolerant behavior, the researchers report in the September issue of Molecular Phylogenetics and Evolution.
Spiders spin various shapes of outer sacs that discourage egg raiders. Spiders in a fixed retreat can conveniently anchor a sac, unlike some other moms that carry eggs with them. Also the more spread-out, plastered form might — Rayor emphasizes this is speculation — fit better in tight crevices than the puffier throw-pillow styles of egg sacs would.
Delena spiderlings still carry abundant egg yolk with them when they clamber out of the egg sac. They don’t eat until after their first molt. “They’ve got these big, fat, green abdomens,” Rayor says. “They don’t have long legs, so they waddle.”
Once they molt, one benefit of this family lifestyle could be table scraps for the littles. Very young spiderlings are “ridiculously small,” Rayor says, and can handle food only about the size of a fruit fly. The chance to sneak extra shreds of meat from an older sib could greatly boost nutrition. Older sibs probably would rather not share, but Rayor sees “tolerated theft.”
Cute babies may not matter to a spider mom, but maybe they should to humans. Gorneau, once “very afraid of spiders,” wants to fight the stereotype of spiders as aggressive dangers. Rayor’s spiders strike him as “stoic,” mostly sitting quietly. Rayor’s lab full of spiders in their homes, he now finds, is a “calming environment.”
A century from now, when biologists are playing games of clones and engineers are playing games of drones, physicists will still pledge their loyalty to the Kingdoms of Substance and Force.
Physicists know the subjects of these kingdoms as fermions and bosons. Fermions are the fundamental particles of matter; bosons transmit forces that govern the behavior of the matter particles. The math describing these particles and their relationships forms the “standard model” of particle physics. Or as Nobel laureate Frank Wilczek calls it, “The Core Theory.” Wilczek’s core theory differs from the usual notion of standard model. His core includes gravity, as described by Einstein’s general theory of relativity. General relativity is an exquisite theory of gravity, but it doesn’t fit in with the math for the standard model’s three forces (the strong and weak nuclear forces and electromagnetism). But maybe someday it will. Perhaps even by 100 years from now.
At least, that’s among the many predictions that Wilczek has made for the century ahead. In a recent paper titled “Physics in 100 Years,” he offers a forecast for future discoveries and inventions that science writers of the future will be salivating over. (The paper is based on a talk celebrating the 250th anniversary of Brown University. He was asked to make predictions for 250 years from now, but regarded 100 as more reasonable.)
Wilczek does not claim that his forecast will be accurate. He considers it more an exercise in imagination, anchored in thorough knowledge of today’s major questions and the latest advances in scientific techniques and capabilities. Where those two factors meet, Wilczek sees the potential for premonition. His ruminations result in a vision of the future suitable for a trilogy or two of science fiction films. They would involve the unification of the kingdoms of physics and a more intimate relationship between them and the human mind.
Among Wilczek’s prognostications is the discovery of supersymmetric particles, heavyweight partners to the matter and force particles of the Core Theory. Such partner particles would reveal a deep symmetry underlying matter and force, thereby combining the kingdoms and further promoting the idea of unification as a key path to truth about nature. Wilczek also foresees the discovery of proton decay, even though exhaustive searches for it have so far failed to find it. If protons disintegrate (after, on average, trillions upon trillions of years), matter as we know it has a limited lease on life. On the other hand, lack of finding proton decay has been a barrier to figuring out a theory that successfully unifies the math for all of nature’s particles and forces. And Wilczek predicts that:
The unification of gravity with the other forces will become more intimate, and have observable consequences.
He also anticipates that gravity waves will be observed and used to probe the physics of the distant (and early) universe; that the laws of physics, rather than emphasizing energy, will someday be rewritten in terms of “information and its transformations”; and that “biological memory, cognitive processing, motivation, and emotion will be understood at the molecular level.”
And all that’s just the beginning. He then assesses the implications of future advances in computing. Part of the coming computation revolution, he foresees, will focus on its use for doing science:
Calculation will increasingly replace experimentation in design of useful materials, catalysts, and drugs, leading to much greater efficiency and new opportunities for creativity.
Advanced calculational power will also be applied to understanding the atomic nucleus more precisely, conferring the ability…
to manipulate atomic nuclei dexterously … enabling (for example) ultradense energy storage and ultrahigh energy lasers.
Even more dramatically, computing power will be employed to enhance itself:
Capable three-dimensional, fault-tolerant, self-repairing computers will be developed.… Self-assembling, self-reproducing, and autonomously creative machines will be developed.
And those achievements will imply that:
Bootstrap engineering projects wherein machines, starting from crude raw materials, and with minimal human supervision, build other sophisticated machines (notably including titanic computers) will be underway.
Ultimately, such sophisticated computing machines will enable artificial intelligence that would even impress Harold Finch on Person of Interest (which is probably Edward Snowden’s favorite TV show).
Imagine, for instance, the ways that superpowerful computing could enhance the human senses. Aided by electronic prosthetics, people could experience the full continuous range of colors in the visible part of the electromagnetic spectrum, not just those accessible to the tricolor-sensitive human eye. Perhaps the beauty that physicists and mathematicians “see” in their equations can be transformed into works of art beamed directly into the brain.
Artificial intelligence endowed with such power would enable many other futuristic fantasies. As Wilczek notes, the “life of mind” could be altered in strange new ways. For one thing, computationally precise knowledge of a state of mind would permit new possibilities for manipulating it. “An entity capable of accurately recording its state could purposefully enter loops, to re-live especially enjoyable episodes,” Wilczek points out.
And if all that doesn’t sound weird enough, we haven’t even invoked quantum mechanics yet. Wilczek forecasts that large-scale quantum computers will be realized, in turn leading to “quantum artificial intelligence.”
“A quantum mind could experience a superposition of ‘mutually contradictory’ states, or allow different parts of its wave function to explore vastly different scenarios in parallel,” Wilczek points out. “Being based on reversible computation, such a mind could revisit the past at will, and could be equipped to superpose past and present.”
And with quantum artificial intelligence at its disposal, the human mind’s sensory tentacles will not merely be enhanced but also dispersed. With quantum communication, humans can be linked by quantum messaging to sensory devices at vast distances from their bodies. “An immersive experience of ‘being there’ will not necessarily involve being there, physically,” Wilczek writes. “This will be an important element of the expansion of human culture beyond Earth.”
In other words, it will be a web of intelligence, rather than a network of physical settlements, that will expand human culture throughout the cosmos. Such “expanded identities” will be able to comprehend the kingdoms of substance and force on their own quantum terms, as the mind itself merges with space and time.
Wilczek’s visions imply a future existence in which nature is viewed from a vastly different perspective, conditioned by a radical reorientation of the human mind to its world. And perhaps messing with the mind so drastically should be worrisome. But let’s not forget that the century gone by has also messed with the mind and its perspectives in profound ways — with television, for instance, talk radio, the Internet, smartphones and blogs. A little quantum computer mind manipulation is unlikely to make things any worse.
Pocket gophers certainly don’t qualify as card-carrying 4-H members, but the rodents might be farming roots in the open air of their moist, nutrient-rich tunnels.
The gophers subsist mostly on roots encountered in the tunnels that the rodents excavate. But the local terrain doesn’t always provide enough roots to sustain gophers, two researchers report in the July 11 Current Biology. To make up the deficit, the gophers practice a simple type of agriculture by creating conditions that promote more root growth, suggest ecologist Jack Putz of the University of Florida in Gainesville and his former zoology undergraduate student Veronica Selden. But some scientists think it’s a stretch to call the rodents’ activity farming. Gophers aren’t actively working the soil, these researchers say, but inadvertently altering the environment as the rodents eat and poop their way around — much like all animals do.
Tunnel digging takes a lot of energy — up to 3,400 times as much as walking along the surface for gophers. To see how the critters were getting all this energy, Selden and Putz in 2021 began investigating the tunnels of southeastern pocket gophers (Geomys pinetis) in an area being restored to longleaf pine savanna in Florida that Putz partially owns.
The pair took root samples from soil adjacent to 12 gopher tunnels and extrapolated how much root mass a gopher would encounter as it excavated a meter of tunnel. Then the researchers calculated the amount of energy that those roots would provide.
“We were able to compare energy cost versus gain, and found that on average there is a deficit, with about half the cost of digging being unaccounted for,” Selden says.
Upon examining some tunnels, Selden and Putz saw gopher feces spread through the interior along with signs of little bites taken out of roots and churning of the soil.
The gophers, the researchers conclude, provide conditions that favor root growth by spreading their own waste as fertilizer, aerating the soil and repeatedly nibbling on roots to encourage new sprouting. “All of these activities encourage root growth, and once the roots grow into the tunnels, the gophers crop the roots,” Selden says. She and Putz say that this amounts to a rudimentary form of farming. If so, gophers would be the first nonhuman mammals to be recognized as farmers, Putz says. Other organisms, such as some insects, also farm food and started doing so much earlier than humans (SN: 4/23/20).
But the study has its skeptics. “I don’t really think you can call it farming per the human definition. All herbivores eat plants, and everybody poops,” says J.T. Pynne, a wildlife biologist at the Georgia Wildlife Federation in Covington who studies southeastern pocket gophers. So the root nibbling and tunnel feces might not be signs of agriculture, just gophers doing what all animals do.
Evolutionary biologist Ulrich Mueller agrees. “If we accept the tenuous evidence presented in the Selden article as evidence for farming … then most mammals and most birds are farmers because each of them accidentally have also some beneficial effects on some plants that these mammals or birds also feed on,” he says.
Not only that, but the study is also dangerous, says Mueller, of the University of Texas at Austin. The public will see through “the shallowness of the data,” he says, and will conclude that science is “just a bunch of storytelling, eroding general trust in science.”
For her part, Selden says she understands that because gophers don’t plant their crops, not everyone is comfortable calling them farmers. Still, she argues that “what qualifies the gophers as farmers and sets them apart from, say, cattle, which incidentally fertilize the grass they eat with their wastes, is that gophers cultivate and maintain this ideal environment for roots to grow into.”
At the very least, Putz says, he hopes their research makes people kinder toward the rodents. “If you go to the web and put in ‘pocket gopher,’ you’ll see more ways to kill them than you can count.”
Biologist Martin Dančák didn’t set out to find a plant species new to science. But on a hike through a rainforest in Borneo, he and colleagues stumbled on a subterranean surprise.
Hidden beneath the soil and inside dark, mossy pockets below tree roots, carnivorous pitcher plants dangled their deathtraps underground. The pitchers can look like hollow eggplants and probably lure unsuspecting prey into their sewer hole-like traps. Once an ant or a beetle steps in, the insect falls to its death, drowning in a stew of digestive juices (SN: 11/22/16). Until now, scientists had never observed pitcher plants with traps almost exclusively entombed in earth. “We were, of course, astonished as nobody would expect that a pitcher plant with underground traps could exist,” says Dančák, of Palacký University in Olomouc, Czech Republic.
That’s because pitchers tend to be fragile. But the new species’ hidden traps have fleshy walls that may help them push against soil as they grow underground, Dančák and colleagues report June 23 in PhytoKeys. Because the buried pitchers stay concealed from sight, the team named the species Nepenthes pudica, a nod to the Latin word for bashful.
The work “highlights how much biodiversity still exists that we haven’t fully discovered,” says Leonora Bittleston, a biologist at Boise State University in Idaho who was not involved with the study. It’s possible that other pitcher plant species may have traps lurking underground and scientists just haven’t noticed yet, she says. “I think a lot of people don’t really dig down.”
The next generation of dark matter detectors has arrived.
A massive new effort to detect the elusive substance has reported its first results. Following a time-honored tradition of dark matter hunters, the experiment, called LZ, didn’t find dark matter. But it has done that better than ever before, physicists report July 7 in a virtual webinar and a paper posted on LZ’s website. And with several additional years of data-taking planned from LZ and other experiments like it, physicists are hopeful they’ll finally get a glimpse of dark matter. “Dark matter remains one of the biggest mysteries in particle physics today,” LZ spokesperson Hugh Lippincott, a physicist at the University of California, Santa Barbara said during the webinar.
LZ, or LUX-ZEPLIN, aims to discover the unidentified particles that are thought to make up most of the universe’s matter. Although no one has ever conclusively detected a particle of dark matter, its influence on the universe can be seen in the motions of stars and galaxies, and via other cosmic observations (SN: 7/24/18).
Located about 1.5 kilometers underground at the Sanford Underground Research Facility in Lead, S.D., the detector is filled with 10 metric tons of liquid xenon. If dark matter particles crash into the nuclei of any of those xenon atoms, they would produce flashes of light that the detector would pick up.
The LZ experiment is one of a new generation of bigger, badder dark matter detectors based on liquid xenon, which also includes XENONnT in Gran Sasso National Laboratory in Italy and PandaX-4T in the China Jinping Underground Laboratory. The experiments aim to detect a theorized type of dark matter called Weakly Interacting Massive Particles, or WIMPs (SN: 12/13/16). Scientists scaled up the search to allow for a better chance of spying the particles, with each detector containing multiple tons of liquid xenon.
Using only about 60 days’ worth of data, LZ has already surpassed earlier efforts to pin down WIMPs (SN: 5/28/18). “It’s really impressive what they’ve been able to pull off; it’s a technological marvel,” says theoretical physicist Dan Hooper of Fermilab in Batavia, Ill, who was not involved with the study.
Although LZ’s search came up empty, “the way something’s going to be discovered is when you have multiple years in a row of running,” says LZ collaborator Matthew Szydagis, a physicist at the University at Albany in New York. LZ is expected to run for about five years, and data from that extended period may provide physicists’ best chance to find the particles.
Now that the detector has proven its potential, says LZ physicist Kevin Lesko of Lawrence Berkeley National Laboratory in California, “we’re excited about what we’re going to see.”
Tyrannosaurus rex’s tiny arms have launched a thousand sarcastic memes: I love you this much; can you pass the salt?; row, row, row your … oh.
But back off, snarky jokesters. A newfound species of big-headed carnivorous dinosaur with tiny forelimbs suggests those arms weren’t just an evolutionary punchline. Arm reduction — alongside giant heads — evolved independently in different dinosaur lineages, researchers report July 7 in Current Biology.
Meraxes gigas, named for a dragon in George R. R. Martin’s “A Song of Ice and Fire” book series, lived between 100 million and 90 million years ago in what’s now Argentina, says Juan Canale, a paleontologist with the country’s CONICET research network who is based in Buenos Aires. Despite the resemblance to T. rex, M. gigas wasn’t a tyrannosaur; it was a carcharodontosaur — a member of a distantly related, lesser-known group of predatory theropod dinosaurs. M. gigas went extinct nearly 20 million years before T. rex walked on Earth. The M. gigas individual described by Canale and colleagues was about 45 years old and weighed more than four metric tons when it died, they estimate. The fossilized specimen is about 11 meters long, and its skull is heavily ornamented with crests and bumps and tiny hornlets, ornamentations that probably helped attract mates.
Why these dinosaurs had such tiny arms is an enduring mystery. They weren’t for hunting: Both T. rex and M. gigas used their massive heads to hunt prey (SN: 10/22/18). The arms may have shrunk so they were out of the way during the frenzy of group feeding on carcasses.
But, Canale says, M. gigas’ arms were surprisingly muscular, suggesting they were more than just an inconvenient limb. One possibility is that the arms helped lift the animal from a reclining to a standing position. Another is that they aided in mating — perhaps showing a mate some love.
Getting a COVID-19 test has become a regular part of many college students’ lives. That ritual may protect not just those students’ classmates and professors but also their municipal bus drivers, neighbors and other members of the local community, a new study suggests.
Counties where colleges and universities did COVID-19 testing saw fewer COVID-19 cases and deaths than ones with schools that did not do any testing in the fall of 2020, researchers report June 23 in PLOS Digital Health. While previous analyses have shown that counties with colleges that brought students back to campus had more COVID-19 cases than those that continued online instruction, this is the first look at the impact of campus testing on those communities on a national scale (SN: 2/23/21). “It’s tough to think of universities as just silos within cities; it’s just much more permeable than that,” says Brennan Klein, a network scientist at Northeastern University in Boston.
Colleges that tested their students generally did not see significantly lower case counts than schools that didn’t do testing, Klein and his colleagues found. But the communities surrounding these schools did see fewer cases and deaths. That’s because towns with colleges conducting regular testing had a more accurate sense of how much COVID-19 was circulating in their communities, Klein says, which allowed those towns to understand the risk level and put masking policies and other mitigation strategies in place.
The results highlight the crucial role testing can continue to play as students return to campus this fall, says Sam Scarpino, vice president of pathogen surveillance at the Rockefeller Foundation’s Pandemic Prevention Institute in Washington, D.C. Testing “may not be optional in the fall if we want to keep colleges and universities open safely,” he says. Finding a flight path As SARS-CoV-2, the virus that causes COVID-19 rapidly spread around the world in the spring of 2020, it had a swift impact on U.S. college students. Most were abruptly sent home from their dorm rooms, lecture halls, study abroad programs and even spring break outings to spend what would be the remainder of the semester online. And with the start of the fall semester just months away, schools were “flying blind” as to how to bring students back to campus safely, Klein says.
That fall, Klein, Scarpino and their collaborators began to put together a potential flight path for schools by collecting data from COVID-19 dashboards created by universities and the counties surrounding those schools to track cases. The researchers classified schools based on whether they had opted for entirely online learning or in-person teaching. They then divided the schools with in-person learning based on whether they did any testing.
It’s not a perfect comparison, Klein says, because this method groups schools that did one round of testing with those that did consistent surveillance testing. But the team’s analyses still generally show how colleges’ pandemic response impacted their local communities.
Overall, counties with colleges saw more cases and deaths than counties without schools. However, testing helped minimize the increase in cases and deaths. During the fall semester, from August to December, counties with colleges that did testing saw on average 14 fewer deaths per 100,000 people than counties with colleges that brought students back with no testing — 56 deaths per 100,000 versus about 70. The University of Massachusetts Amherst, with nearly 30,000 undergraduate and graduate students in 2020, is one case study of the value of the testing, Klein says. Throughout the fall semester, the school tested students twice a week. That meant that three times as many tests occurred in the city of Amherst than in neighboring cities, he says. For much of the fall and winter, Amherst had fewer COVID-19 cases per 1,000 residents than its neighboring counties and statewide averages.
Once students left for winter break, campus testing stopped – so overall local testing dropped. When students returned for spring semester in February 2021, area cases spiked — possibly driven by students bringing the coronavirus back from their travels and by being exposed to local residents whose cases may have been missed due to the drop in local testing. Students returned “to a town that has more COVID than they realize” Klein says.
Renewed campus testing not only picked up the spike but quickly prompted mitigation strategies. The university moved classes to Zoom and asked students to remain in their rooms, at one point even telling them that they should not go on walks outdoors. By mid-March, the university reduced the spread of cases on campus and the town once again had a lower COVID-19 case rate than its neighbors for the remainder of the semester, the team found.
The value of testing It’s helpful to know that testing overall helped protect local communities, says David Paltiel, a public health researcher at the Yale School of Public Health who was not involved with the study. Paltiel was one of the first researchers to call for routine testing on college campuses, regardless of whether students had symptoms.
“I believe that testing and masking and all those things probably were really useful, because in the fall of 2020 we didn’t have a vaccine yet,” he says. Quickly identifying cases and isolating affected students, he adds, was key at the time. But each school is unique, he says, and the benefit of testing probably varied between schools. And today, two and a half years into the pandemic, the cost-benefit calculation is different now that vaccines are widely available and schools are faced with newer variants of SARS-CoV-2. Some of those variants spread so quickly that even testing twice a week may not catch all cases on campus quickly enough to stop their spread, he says.
As colleges and universities prepare for the fall 2022 semester, he would recommend schools consider testing students as they return to campus with less frequent follow-up surveillance testing to “make sure things aren’t spinning crazy out of control.”
Still, the study shows that regular campus testing can benefit the broader community, Scarpino says. In fact, he hopes to capitalize on the interest in testing for COVID-19 to roll out more expansive public health testing for multiple respiratory viruses, including the flu, in places like college campuses. In addition to PCR tests — the kind that involve sticking a swab up your nose — such efforts might also analyze wastewater and air within buildings for pathogens (SN: 05/28/20).
Unchecked coronavirus transmission continues to disrupt lives — in the United States and globally — and new variants will continue to emerge, he says. “We need to be prepared for another surge of SARS-CoV-2 in the fall when the schools reopen, and we’re back in respiratory season.”
Some mosquito-borne viruses turn mice into alluring mosquito bait.
Mice infected with dengue or Zika viruses — and people infected with dengue — emit a flowery, orange-smelling chemical that tempts hungry mosquitoes, researchers report June 30 in Cell. In mice, the infections spur the growth of skin-inhabiting bacteria that make the chemical, drawing in bloodsucking Aedes aegypti mosquitoes that could then transmit the viruses to new hosts, including humans.
Previous studies showed that other mosquito species prefer to feed on animals carrying the parasite that causes malaria (SN: 2/9/17). But it was unknown whether the same was true for viruses such as dengue or Zika, says Gong Cheng, a microbiologist at Tsinghua University in Beijing.
The chemical acetophenone — which to humans smells like orange blossom — may be that lure. Mice infected with dengue or Zika viruses give off approximately 10 times more acetophenone and attract more mosquitoes than uninfected animals, Cheng and colleagues found. People infected with dengue similarly release more of the chemical than healthy people. Samples of odors taken from the armpits of infected people also created potent mosquito magnets when smeared on filter paper attached to a volunteer’s palm. Acetophenone typically comes from bacteria. Researchers found that Bacillus bacteria on mice were the likely culprits producing the chemical. An infection stops mice from making an antimicrobial protein called RELMα, allowing the acetophenone-emitting microbes to flourish.
But a component of some acne medications can bring back RELMα in mice, the team found. Infected animals fed a derivative of vitamin A called isotretinoin produced less acetophenone and become less attractive mosquito targets.
It’s possible that giving people isotretinoin could help reduce virus transmission among people by hiding infected people from the bloodsucking insects, Cheng says. He and colleagues are planning to test the strategy in Malaysia, where dengue circulates.
