Anterior insula activation restores prosocial behavior in animal model of opioid addiction

by Arizona State University

Credit: CC0 Public Domain

A new study in animals suggests that the social and interpersonal problems associated with opioid addiction might be reversible.

Researchers in the Arizona State University Department of Psychology previously used an animal model of opioid addiction and empathy to show that animals stopped prosocial behaviors—helping another animal—when heroin was available. The same research group has now shown that activating the anterior insula restored prosocial behaviors in opioid-addicted animals. The study will be published in Social Neuroscience and is now available online.

"As a master's student, I led support groups for opioid addicts, and the biggest problems people wanted help dealing with were social. Our finding in an animal model of opioid addiction that chemogenetic activation of the anterior insula restores prosocial behavior suggests a glimmer of hope that some of the social behavioral deficits in opioid addiction are not permanent," said Seven Tomek, who just defended her doctoral dissertation at ASU. Tomek is first author on the paper and received training in substance abuse treatment while earning her master's in clinical psychology from the University of North Carolina, Wilmington.

To measure prosocial behavior, the researchers trained animals to free another animal that was trapped in a clear plastic tube. The animals had access to heroin for two weeks and then were given the choice of consuming heroin or helping another animal. Like before, the animals again chose heroin over helping another.

To try and restore the prosocial behaviors in the animals, the research team targeted a brain region involved in both prosocial behaviors like helping and addictive behaviors like craving: the anterior insula.

"We designed our animal study based on work in people showing that damage in the anterior insula area—from a stroke for example—was correlated with easily quitting cigarette smoking," Tomek said. "This brain area is also important for motivation and emotions in people."

The insula is nicknamed the "hidden lobe" because it is tucked underneath the brain's frontal, parietal and temporal lobes. This location makes access difficult, so the research team used chemogenetic methods—called Designer Receptors Exclusively Activated by Designer Drugs, or DREADDs for short—to selectively activate the anterior insula in the animals. Using DREADDs is like installing a smart lock on specific neurons, and then only granting access the lock when scientists want to activate the neurons. The DREADD method inserts mutant receptors into neurons, and those receptors can only be activated by a chemical that is not naturally present in the body.

"Once we activated the excitatory DREADD in the anterior insula, the animals started rescuing the trapped animals again," Tomek said.

The research team tested the role of anterior insula activation twice. In the first experiment, the animals who underwent DREADD activation helped other animals 67% of the time when heroin was available. The control group only helped other animals 17% of the time. In the second experiment, activation of the anterior insula was again associated with helping other animals 67% of the time. The second control group helped other animals 44% of the time.

"This work demonstrates an important role for the anterior insula in opioid addiction and shows the possibilities of changing a social behavior that has been compromised by drug use," said Foster Olive, professor of psychology at ASU and senior author on the paper.

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Explore further

Activating parts of the brain could help alleviate opioid-related social isolation

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More information: Seven E. Tomek et al, Restoration of prosocial behavior in rats after heroin self-administration via chemogenetic activation of the anterior insular cortex, Social Neuroscience (2020). DOI: 10.1080/17470919.2020.1746394

Provided by Arizona State 

Plant root hairs key to reducing soil erosion

by University of Bristol

Credit: University of Bristol

The tiny hairs found on plant roots play a pivotal role in helping reduce soil erosion, a new study has found. The research, led by the University of Bristol and published in Communications Biology, provides compelling evidence that when root hairs interact with the surrounding soil they reduce soil erosion and increase soil cohesion by binding soil particles.

Soil erosion can have a devastating impact across the globe and a serious threat for modern agriculture. The increased demand for agriculture has led to forests and natural grasslands being converted to farm fields and pastures.

However, many of the plants grown, such as coffee, cotton and palm oil, can significantly increase soil erosion beyond the soil's ability to maintain and renovate. It can also lead to increased pollution and sedimentation in streams and rivers or, because these areas are often less able to hold onto water, can worsen flooding. This problem is particularly urgent considering the ever-expanding human population and climate change.

Researchers from the Universities of Bristol and Exeter have revealed the crucial function the microscopic roots hairs play in binding and reinforcing soil.

While the larger-scale root properties such as diameter, length and surface area have been extensively studied to understand their role in preventing soil erosion, the effect that micro-scale properties, such as root hairs, has is less well documented.

The research team looked at how wild plants Arabidopsis thaliana, which produced root hairs, compared with an almost identical Arabidopsis with the same root hair structure in reducing soil erosion.

They found that, when planted in sufficient density, plants with root hairs reduced soil loss almost completely—while otherwise identical plants without hairs could not stem the flow of erosion.

Three methods were used to explore the soil retention benefits of root hairs. First, the samples were placed in a sterile gel, in a petri dish, and then subjected to increasing centrifugal force. The study found that the hairless seedlings were easier to remove from the gel compared to seedlings abundant with root hairs.

Second, the study found that root hairs were also shown to stabilise the plant in the soil, as they increased the force needed to uproot the plant.

Third, in the experimental landscapes laboratory at Exeter, root hairs reduced water erosion to almost zero.

Professor Claire Grierson, one of the study's lead authors from Bristol's School of Biological Sciences explained: "These findings could be the key in helping to tackle soil erosion. There are three possible ways root hairs could enhance soil, either the soil might bind directly to root hair surfaces, root hairs might release material that reinforces soil, or root hairs might release material that is processed by microbes into something that can reinforce soil.

"We hope our knowledge about the properties of plants that minimise soil erosion will allow the creation and selection of best-suited agricultural plants."

Professor Quine, an expert in Earth System Science at the University of Exeter, added: "This exciting, truly interdisciplinary project across biology, maths, engineering and environmental science has given us invaluable new insights into the influence of microscopic root structures on the macroscopic behavior of soils.

"I was amazed at the difference that root density made in reducing soil erosion to almost zero, when root density was high, whereas soil loss was still significant when roots at the same density had no hairs.

"We are excited to explore how the hairs exert this extraordinary influence."

The team are now working to distinguish between these hypotheses and identify the molecules involved.

How roots grow hair

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More information: Sarah De Baets et al. Micro-scale interactions between Arabidopsis root hairs and soil particles influence soil erosion, Communications Biology (2020). DOI: 10.1038/s42003-020-0886-4

Journal information: Communications Biology 

Clues to COVID-19 coronavirus's vulnerability emerge from an antibody against SARS

by The Scripps Research Institute

Antibody CR3022 bound to the receptor binding domain of SARS2-CoV-2. Credit: Meng Yuan and Nicholas Wu

An antibody recovered from a survivor of the SARS epidemic in the early 2000s has revealed a potential vulnerability of the new coronavirus at the root of COVID-19, according to a study from scientists at Scripps Research.

The study, published today in Science, is the first to map a human antibody's interaction with the new coronavirus at near-atomic-scale resolution. Although the antibody was produced in response to an infection of SARS (severe acute respiratory syndrome), which is caused by the SARS-CoV virus, it cross-reacts with the new coronavirus, SARS-CoV-2.

The structural mapping revealed a nearly identical site on both coronaviruses to which the antibody binds, suggesting a functionally important and vulnerable site for this family of coronaviruses.

"The knowledge of conserved sites like this can aid in structure-based design of vaccines and therapeutics against SARS-CoV-2, and these would also protect against other coronaviruses—including those that may emerge in the future," says the study's senior author Ian Wilson, DPhil, Hansen Professor of Structural Biology and Chair of the Department of Integrative Structural and Computational Biology at Scripps Research.

SARS-CoV, which causes SARS, originated in horseshoe bats, but jumped to humans in South China in 2002, eventually infecting more than 8,000 people and killing almost 800 before it was quelled by lockdowns, quarantines and other measures.

SARS-CoV-2, a closely related coronavirus that causes COVID-19, first emerged in the Chinese city of Wuhan in late 2019. Much more infectious than its viral cousin, it has led to a pandemic, causing far more cases of illness and fatalities than SARS. The development of a vaccine or even an effective treatment could significantly ameliorate the crisis.

The Wilson lab is known for its pioneering structural studies of antibodies bound to viruses including HIV and influenza. These studies have been used to inform designs of vaccines and antibody drugs, as well as other therapeutics. Along with hundreds of other labs around the world, Wilson's team is now focused on SARS-CoV-2.

"Our ultimate goal here is to obtain structural information on antibodies and their binding sites, and use that to guide SARS-CoV-2 vaccine design, just as our lab has done with influenza and HIV," says the study's co-first author Nicholas Wu, Ph.D., a postdoctoral research associate in the Wilson lab.

The new study centers on an anti-SARS-CoV antibody called CR3022 that was originally isolated in 2006 by the pharmaceutical company Crucell Holland B.V. in the Netherlands. A report from Chinese scientists earlier this year indicated that CR3022 cross-reacts against SARS-CoV-2. Wilson's team used their structural mapping expertise to determine how the antibody binds to SARS-CoV-2.

A key finding is that the antibody's binding site is highly similar between the two coronaviruses—differing by just four protein building blocks called amino-acids. That high degree of similarity implies that the site has an important function that would be lost if it mutated significantly.

Yet, the site's function remains mysterious. The Scripps Research analysis found that the antibody binding site is relatively remote from the part of the virus that grabs hold of cell-surface protein receptors in preparation for penetrating cells in our lungs. That suggests that, at least for SARS-CoV, CR3002 neutralizes the virus's ability to infect cells in some indirect way.

Adding to the mystery is the finding that the antibody binding site on these viruses is not normally accessible to antibodies.

"We found that this region is usually hidden inside the virus, and only exposed when that part of the virus changes its structure, as it would in natural infection," says co-first author Meng Yuan, Ph.D., also a research associate in the Wilson lab.

Despite the slightness of difference between the two coronaviruses, the antibody binds much less tightly to SARS-CoV-2 than it does to the SARS virus, and cannot neutralize SARS-CoV-2 in lab dish tests as it does SARS-CoV.

Still, the findings suggest that the binding site for this antibody on SARS-CoV-2 is a site of vulnerability, and that antibodies binding it more tightly would plausibly succeed in neutralizing the virus. Such neutralizing antibodies, if developed into therapies, could be used to treat COVID-19 patients and to provide temporary protection from the virus to uninfected individuals, for example healthcare workers.

The fact that this binding site is highly conserved between SARS-CoV and SARS-CoV-2 also hints that there may be antibodies, still to be discovered, that can effectively neutralize both viruses—and perhaps in the same way, can neutralize future emergent coronaviruses before they can cause pandemics.

Labs at Scripps Research and throughout the world are currently seeking antibodies, via blood donations, from people who have recovered from COVID-19 for further studies along these lines.How the novel coronavirus binds to human cells

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More information: Meng Yuan et al. A highly conserved cryptic epitope in the receptor-binding domains of SARS-CoV-2 and SARS-CoV, (2020). DOI: 10.1101/2020.03.13.991570

Alphabet's DeepMind masters Atari games

I MASTERED THEM TOO DIDN'T YOU

by Peter Grad , Tech Xplore

Illustration of the mean, median and 5th percentile performance of two hypothetical agents on the same benchmark set of 20 tasks. Credit: Google

In order to better solve complex challenges at the dawn of the third decade of the 21st century, Alphabet Inc. has tapped into relics dating to the 1980s: video games.

The parent company of Google reported this week that its DeepMind Technologies Artificial Intelligence unit has successfully learned how to play 57 Atari video games. And the computer system plays better than any human.

Atari, creator of Pong, one of the first successful video games of the 1970s, went on to popularize many of the great early classic video games into the 1990s. Video games are commonly used with AI projects because they challenge algorithms to navigate increasingly complex paths and options, all while encountering changing scenarios, threats and rewards.

Dubbed AGENT57, Alphabet's AI system probed 57 leading Atari games covering a huge range of difficulty levels and varying strategies of success.

"Games are an excellent testing ground for building adaptive algorithms," the researchers said in a report on the DeepMind blog page. "They provide a rich suite of tasks which players must develop sophisticated behavioral strategies to master, but they also provide an easy progress metric —game score—to optimize against.

"The ultimate goal is not to develop systems that excel at games, but rather to use games as a stepping stone for developing systems that learn to excel at a broad set of challenges," the report said.

DeepMind's AlphaGo system earned wide recognition in 2016 when it beat world champion Lee Sedol in the strategic game of Go.

Among the current crop of 57 Atari games, four are considered especially difficult for AI projects to master: Montezuma's Revenge, Pitfall, Solaris and Skiing. The first two games pose what DeepMind calls the perplexing "exploration-exploitation problem."

"Should one keep performing behaviors one knows works (exploit), or should one try something new (explore) to discover new strategies that might be even more successful?" DeepMind asks. "For example, should one always order their same favorite dish at a local restaurant, or try something new that might surpass the old favorite? Exploration involves taking many suboptimal actions to gather the information necessary to discover an ultimately stronger behavior."

The other two challenging games impose long waiting times between challenges and rewards, making it more difficult for AI systems to successful analyze.

Previous efforts to master the four games with AI all failed.

The report says there is still room for improvement. For one, long computational times remain an issue. Also, while acknowledging that "the longer it trained, the higher its score got," DeepMind researchers want Agent57 to do better. They want it to master multiple games simultaneously; currently, it can learn only one game at a time and it must go through training each time it restarts a game.

Ultimately, DeepMind researchers foresee a program that can apply human-like decision-making choices while encountering ever-changing and previously unseen challenges.

"True versatility, which comes so easily to a human infant, is still far beyond AIs' reach," the report concluded.

Atari master: New AI smashes Google DeepMind in video game challenge

"The ultima
te goal is not to develop systems that excel at games, but rather to use games as a stepping stone for developing systems that learn to excel at a broad set of challenges," the report said.DeepMind's AlphaGo system earned wide recognition in 2016 when it beat world champion Lee Sedol in the strategic game of Go.Among the current crop of 57 Atari games, four are considered especially difficult for AI projects to master: Montezuma's Revenge, Pitfall, Solaris and Skiing. The first two games pose what DeepMind calls the perplexing "exploration-exploitation problem."

"Should one keep performing behaviors one knows works (exploit), or should one try something new (explore) to discover new strategies that might be even more successful?" DeepMind asks. "For example, should one always order their same favorite dish at a local restaurant, or try something new that might surpass the old favorite? Exploration involves taking many suboptimal actions to gather the information necessary to discover an ultimately stronger behavior."The other two challenging games impose long waiting times between challenges and rewards, making it more difficult for AI systems to successful analyze.Previous efforts to master the four games with AI all failed.

The report says there is still room for improvement. For one, long computational times remain an issue. Also, while acknowledging that "the longer it trained, the higher its score got," DeepMind researchers want Agent57 to do better. They want it to master multiple games simultaneously; currently, it can learn only one game at a time and it must go through training each time it restarts a game.Ultimately, DeepMind researchers foresee a program that can apply human-like decision-making choices while encountering ever-changing and previously unseen challenges."True versatility, which comes so easily to a human infant, is still far beyond AIs' reach," the report concluded.Atari master: New AI smashes Google DeepMind in video game challenge

UPDATED 
Coronavirus may spread through normal breathing: 
US scientists

Issam AHMED,AFP•April 3, 2020

Washington (AFP) - The new coronavirus might spread through the air via normal breathing and speaking, a top US scientist said Friday as the government was poised to recommend the use of face masks for everyone.

Anthony Fauci, head of infectious diseases at the National Institutes of Health, told Fox News the guidance on masks would be changed "because of some recent information that the virus can actually be spread even when people just speak, as opposed to coughing and sneezing."

As it stands, the official advice is that only sick people need to cover their faces, as well as those caring for them at home.

Fauci's comments come after the National Academy of Sciences (NAS) sent a letter to the White House on April 1 that summarized recent research on the subject.

It said that though the research isn't yet conclusive, "the results of available studies are consistent with aerosolization of virus from normal breathing."

Until now, US health agencies have said that the primary pathway of transmission is respiratory droplets, about one millimeter in diameter, expelled by sick people when they sneeze or cough.

These quickly fall to the ground around a meter away.

But if the virus can be suspended in the ultrafine mist we expel when we exhale, in other words an aerosol, it becomes much harder to prevent its spread, which in turn is an argument in favor of everyone covering their faces.

- The aerosol debate -

A recent NIH funded study published in the New England Journal of Medicine found that the SARS-CoV-2 virus could become an aerosol and remain airborne for up to three hours.

This triggered a debate even as critics said the findings were overblown because the team behind the study used a medical device called a nebulizer to deliberately create a viral mist and argued this would not occur naturally.

The NAS letter pointed to preliminary research by the University of Nebraska Medical Center that found the genetic code of the SARS-CoV-2 virus, its RNA, were found in hard to reach areas of patients' isolation rooms.

The NAS scientists also pointed to two other studies -- both not yet peer reviewed -- from Hong Kong and from mainland China.

The Hong Kong researchers collected viral samples from patients with the coronavirus and other viral respiratory illnesses, and gave some of the patients face masks.

The masks reduced the detection of both droplets and aerosols for coronavirus patients.

The Chinese paper on the other hand raised concerns that personal protective gear used by health care workers could itself be a source of airborne virus.

The team studied hospitals in Wuhan and found that there were two major areas where the virus was aerosolized: the bathrooms of patients, and rooms where medical staff removed their protective gear.

This may be because doffing protective gear causes the particles to get re-suspended in the air. Even if these particles are not of breathable size, they could settle on people's hands and bodies, the NAS panel said.

So far, the World Health Organization (WHO) has been more cautious on the airborne threat.

In an analysis published on March 29, it wrote that aerosol transmission was only known to occur during particular medical treatments that required assisted breathing.

On the recent preliminary research, such as the University of Nebraska's paper, the WHO cautioned that the detection of the virus' genetic code in patient's rooms did not necessarily amount to viable amounts of the pathogen that could be transmitted onward.

Coronavirus may spread through normal breathing

US scientists

Credit: CC0 Public Domain

The new coronavirus might spread through the air via normal breathing and speaking, a top US scientist said Friday as the government was poised to recommend the use of face masks for everyone.

Anthony Fauci, head of infectious diseases at the National Institutes of Health, told Fox News the guidance on masks would be changed "because of some recent information that the virus can actually be spread even when people just speak, as opposed to coughing and sneezing."

As it stands, the official advice is that only sick people need to cover their faces, as well as those caring for them at home.

Fauci's comments come after the National Academy of Sciences (NAS) sent a letter to the White House on April 1 that summarized recent research on the subject.

It said that though the research isn't yet conclusive, "the results of available studies are consistent with aerosolization of virus from normal breathing."

Until now, US health agencies have said that the primary pathway of transmission is respiratory droplets, about one millimeter in diameter, expelled by sick people when they sneeze or cough.

These quickly fall to the ground around a meter away.

But if the virus can be suspended in the ultrafine mist we expel when we exhale, in other words an aerosol, it becomes much harder to prevent its spread, which in turn is an argument in favor of everyone covering their faces.

The aerosol debate

A recent NIH funded study published in the New England Journal of Medicine found that the SARS-CoV-2 virus could become an aerosol and remain airborne for up to three hours.

This triggered a debate even as critics said the findings were overblown because the team behind the study used a medical device called a nebulizer to deliberately create a viral mist and argued this would not occur naturally.

The NAS letter pointed to preliminary research by the University of Nebraska Medical Center that found the genetic code of the SARS-CoV-2 virus, its RNA, were found in hard to reach areas of patients' isolation rooms.

The NAS scientists also pointed to two other studies—both not yet peer reviewed—from Hong Kong and from mainland China.

The Hong Kong researchers collected viral samples from patients with the coronavirus and other viral respiratory illnesses, and gave some of the patients face masks.

The masks reduced the detection of both droplets and aerosols for coronavirus patients.

The Chinese paper on the other hand raised concerns that personal protective gear used by health care workers could itself be a source of airborne virus.

The team studied hospitals in Wuhan and found that there were two major areas where the virus was aerosolized: the bathrooms of patients, and rooms where medical staff removed their protective gear.

This may be because doffing protective gear causes the particles to get re-suspended in the air. Even if these particles are not of breathable size, they could settle on people's hands and bodies, the NAS panel said.

So far, the World Health Organization (WHO) has been more cautious on the airborne threat.

In an analysis published on March 29, it wrote that aerosol transmission was only known to occur during particular medical treatments that required assisted breathing.

On the recent preliminary research, such as the University of Nebraska's paper, the WHO cautioned that the detection of the virus' genetic code in patient's rooms did not necessarily amount to viable amounts of the pathogen that could be transmitted onward.Air samples from coronavirus patient rooms being analyzed

How important is speech in transmitting coronavirus?

by Andy Fell, UC Davis

Credit: CC0 Public Domain

Normal speech by individuals who are asymptomatic but infected with coronavirus may produce enough aerosolized particles to transmit the infection, according to aerosol scientists at the University of California, Davis. Although it's not yet known how important this is to the spread of COVID-19, it underscores the need for strict social distancing measures—and for virologists, epidemiologists and engineers who study aerosols and droplets to work together on this and other respiratory diseases.

Aerosols are particles small enough to travel through the air. Ordinary speech creates significant quantities of aerosols from respiratory particles, said William Ristenpart, professor of chemical engineering at UC Davis. Ristenpart is co-author on an editorial about the problem published this week in the journal Aerosol Science and Technology.

These respiratory particles are about one micron, or one micrometer, in diameter. That's too small to see with the naked eye, but large enough to carry viruses such as influenza or SARS-CoV-2.

Some individuals superemitters

Last year, Ristenpart, graduate student Sima Asadi and colleagues published a paper showing that the louder one speaks, the more particles are emitted and that some individuals are "superemitters" who give off up to 10 times as many particles as others. The reasons for this are not yet clear. In a follow-up study published in January in PLOS One, they investigated which speech sounds are associated with the most particles.

Calculating just how easily a virus like SARS-CoV-2 spreads through droplets requires expertise from different fields. From virology, researchers need to know how many viruses are in lung fluids, how easily they form into droplets and how many viruses are needed to start an infection. Aerosol scientists can study how far droplets travel once expelled, how they are affected by air motion in a room and how fast they settle out due to gravity.

"The aerosol science community needs to step up and tackle the current challenge presented by COVID-19, and also help better prepare us for inevitable future pandemics," Ristenpart and colleagues conclude.

Hopes for pandemic respite this spring may depend upon what happens indoors

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More information: Sima Asadi et al. Effect of voicing and articulation manner on aerosol particle emission during human speech, PLOS ONE (2020). DOI: 10.1371/journal.pone.0227699

Journal information: PLoS ONE 

Wearing surgical masks in public could help slow COVID-19 pandemic's advance: study

by University of Maryland

Virus shedding by participants was measured using the Gesundheit II machine developed by the University of Maryalnd's Dr. Don Milton Credit: University of Maryland School of Public Health

Surgical masks may help prevent infected people from making others sick with seasonal viruses, including coronaviruses, according to new research that could help settle a fierce debate spanning clinical and cultural norms.

In laboratory experiments, the masks significantly reduced the amounts of various airborne viruses coming from infected patients, measured using the breath-capturing "Gesundheit II machine" developed by Dr. Don Milton, a professor of applied environmental health in the University of Maryland School of Public Health and a senior author of the study published April 3 in the journal Nature Medicine.

Milton has already conferred with federal and White House health officials on the findings, which closely follow statements this week from the head of the Centers for Disease Control and Prevention saying the agency was reconsidering oft-stated advice that surgical masks aren't a useful precaution outside of medical settings. (The debate takes place at a time when clinicians themselves face dangerously inadequate supplies of masks—a shortfall other UMD researchers are scrambling to help solve.)

The question of masks has roiled society as well, with some retailers refusing to let employees wear them for fear of sending negative signals to customers, and cases of slurs and even physical attacks in the United States and elsewhere against Asians or Asian Americans who were wearing masks, a measure some consider a necessity during a disease outbreak.

The study, conducted prior to the current pandemic with a student of Milton's colleagues on the Faculty of Medicine at the University of Hong Kong, does not address the question of whether surgical masks protect wearers from infection. It does suggest that masks may limit how much the infected—who in the case of the novel coronavirus often don't have symptoms—spread diseases including influenza, rhinoviruses and coronaviruses.

Milton, who runs the Public Health Aerobiology, Virology, and Exhaled Biomarker Laboratory in the School of Public Health, demonstrated in a 2013 study that surgical masks could help limit flu transmission. However, he cautions that the effect may not be as great outside of controlled settings.


Nevertheless, he said, the chance they could help justifies taking a new look at whether all people should be encouraged to wear them when they venture out of their houses to stores or other populated locations during the current COVID-19 lockdown.

"In normal times we'd say that if it wasn't shown statistically significant or the effective in real-world studies, we don't recommend it," he said. "But in the middle of a pandemic, we're desperate. The thinking is that even if it cuts down transmission a little bit, it's worth trying."

Previous studies have shown that coronavirus and other respiratory infections are mostly spread during close contact, which has been interpreted by some infectious disease specialists to mean that the disease could spread only through contact and large droplets, such as from a cough or sneeze—a message that has often been shared with the public.

"What they don't understand is that is merely a hypothesis," Milton said. The current study (along with earlier ones) shows, by contrast, that tiny, aerosolized droplets can indeed diffuse through the air. That means it may be possible to contract COVID-19 not only by being coughed on, but by simply inhaling the breath of someone nearby who has it, whether they have symptoms or not. Surgical masks, however, catch a lot of the aerosolized virus as it's exhaled, he said.

The study was conducted at the University of Hong Kong as part of the dissertation research of the lead author, Dr. Nancy Leung, who, under the supervision of the co-senior authors Drs. Cowling and Milton, recruited 246 people with suspected respiratory viral infections. Milton's Gesundheit machine compared how much virus they exhaled with and without a surgical mask.

"In 111 people infected by either coronavirus, influenza virus or rhinovirus, masks reduced detectable virus in respiratory droplets and aerosols for seasonal coronaviruses, and in respiratory droplets for influenza virus," Leung said. "In contrast, masks did not reduce the emission of rhinoviruses."

Although the experiment took place before the current pandemic, COVID-19 and seasonal coronaviruses are closely related and may be of similar particle size. The report's other senior author, Professor Benjamin Cowling, division head of epidemiology and biostatistics, School of Public Health, HKUMed, and co-director of the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, said, "The ability of surgical masks to reduce seasonal coronavirus in respiratory droplets and aerosols implies that such masks can contribute to slowing the spread of (COVID-19) when worn by infected people."

Milton pointed to other measures his research has found is even more effective than masks, such as improving ventilation in public places like grocery stores, or installing UV-C lights near the ceiling that works in conjunction with ceiling fans to pull air upwards and destroy viruses and bacteria.

"Personal protective equipment like N95 masks are not our first line of defense," Milton said. "They are our last desperate thing that we do."

Explore further

Should we wear masks or not? An expert sorts through the confusion
More information: Nancy H. L. Leung et al, Respiratory virus shedding in exhaled breath and efficacy of face masks, Nature Medicine (2020). DOI: 10.1038/s41591-020-0843-2

Journal information: Nature Medicine

Unsustainable food systems: 

Can we reverse current trends?

by International Center for Tropical Agriculture (CIAT)

A bean market in Kampala, Uganda. Credit: Neil Palmer / International Center for 

Tropical Agriculture

As rural masses migrate to urban areas, populations grow, and people work toward better living standards, global food system sustainability is jeopardized, according to a new analysis spanning low- to high-income countries. The study, which was published April 3 in the scientific journal PLOS ONE, shows that only one major global driver—the increase in international trade flows—appears to have a net positive effect on global food systems sustainability. All other major drivers (population growth, urbanization, lifestyle change, and changes in land use) seem to have negative effects.

"Trade seems to be good for food systems—but only up to a point," said Steven Prager, a study co-author from the Alliance of Bioversity International and CIAT. "Beyond a certain level, the positive effect of trade tends to plateau. High-income countries simply don't continue to benefit."

In the context of the COVID-19 pandemic, the immediate focus of the research community is, correctly, on human health. But global disturbances sparked by the pandemic also reveal how fragile our global food systems are.

In those conditions, "Understanding what drives our food systems and how we can measure or monitor them becomes vital if we want to give policymakers better tools for making food systems more sustainable and more resilient to local or global shocks such as the extreme one we are experiencing today," said Christophe Béné, the study's lead author.

Helping policymakers "understand the dynamic of our food systems"

The study builds on a global map of food system sustainability published in November in Scientific Data. That study showed that high-income countries tend to have a higher level of food system sustainability (despite all the junk food they consume) than lower-income countries. Those findings were one of the motivations behind the new study. Its authors wanted to understand what drives those different levels of sustainability and what can be done to improve the situation.

"Local and global food systems are simply reflecting the ways the world is evolving," said Jessica Fanzo, a co-author and associate professor of global food and agricultural policy and ethics at the Johns Hopkins School of Advanced International Studies.

"Some of the key drivers of the global demographic transition that the world is experiencing right now are also heavily impacting our food systems," said Fanzo, who was also the team leader on the 2017 report by the High Level Panel of Experts on Food Security and Nutrition, an initiative of the Food and Agriculture Organization of the United Nations.

The problem is that all these drivers, so far, have had a negative impact on food systems and these drivers are very difficult to control.

"It would be very difficult to prevent people from migrating to cities or from embracing new lifestyles as their income rises," said Fanzo. "We need therefore to find very rapidly the way to reverse or mitigate the consequences of these trends."

Though the results of the study point to some serious challenges ahead, they also offer some initial indications for policymakers about where to direct effort and investment to improve the long-term sustainability of our food systems.A new world map rates food sustainability for countries across the globe

More information: PLOS ONE (2020). DOI: 10.1371/journal.pone.0231071

When what-if scenarios turn real: Pandemic modelers providing new COVID-19 insights

by Colorado State University

Credit: CC0 Public Domain

As a Yale University postdoctoral researcher, economist Jude Bayham studied the potential consequences of a global pandemic that could shutter schools, close businesses, and strain hospitals. That was back in 2013.

Now, as the world grapples with the coronavirus, the Colorado State University economist and a multi-institutional team are turning those prescient modeling exercises into real insights for policymakers.

"We're repurposing models we had done a while back that frankly at the time, people didn't really care about," said Bayham, assistant professor in the Department of Agricultural and Resource Economics. "It's an 'I told you so' moment. I'm not happy about it. It's unfortunate."

In the last several weeks, Bayham and Yale collaborator Eli Fenichel have run a series of analyses illustrating the toll that long-term school closures may have on U.S. health care providers. They're now fielding inquiries from all over the world, from state governments to child care needs assessment professionals, who think the economists' work could help them navigate the here and now. In the last two weeks, the researchers created an interactive dashboard for drilling down statistics on child care needs by state, city and industry sector. Their data were published in The Lancet Public Health April 3.

Bayham and Fenichel have also created another dashboard for viewing COVID-19 complication risk factors in the workforce.

A third of health workers care for young children

For their health care worker analysis, the researchers used data from the U.S. Current Population Survey to show that about a third of health care workers—doctors, nurses, hospital staff—care for children ages 3-12. Fifteen percent of those households don't have other adults or older children who can help with child care.

At the time they did their original analysis, a long-term school closure was a far-off hypothetical. Now, as school districts nationwide shutter for weeks or months, Bayham's work of yore takes on new significance, and the team is scrambling to update it with current figures.

School closures are intended to slow the transmission of the virus. But Bayham and Fenichel find that the toll school closures take on health care workers could potentially negate any mortality benefits from the closures. Their calculations indicate that if the health care workforce declines by 15 percent, due to the workers now having to care for their children, it could lead to an increase in coronavirus deaths, because the workers aren't there to care for sick people. Specifically, they report that assuming a 15 percent loss of the health care labor force, a coronavirus infection mortality rate increase of just 0.35 percentage points would net a greater number of deaths than would be prevented by the closures.

These calculations are just that—calculations, which don't take into account, for example, the potential rollout of state or federal programs to offer child care relief to workers. And the estimates aren't perfect; the researchers don't claim to know, down to a precise number, what one health care worker's absence portends.

"We don't know, in terms of a productivity measure, the estimate of one nurse saving this many lives or reducing mortality," Bayham said. "But we think it's not zero. So essentially we are getting at how productive they need to be for us to be concerned about how school closures would undermine the goal of saving lives."

The work is a sobering reminder of the societal and public-health tradeoffs of large-scale disruptions like long-term school closures.

Forming networks

As the pandemic continues to unfold, Bayham and colleagues at Yale, Northwestern University and other institutions have quickly formed a network of economists and epidemiologists to continue this and other lines of work. They hope to help inform decisionmakers on questions not only of tradeoffs of school closures, but also, strategies for peeling back such restrictive measures when the time is right.

As researchers all over the world converge their expertise around the pandemic, Bayham and colleagues are also jumping into other projects to help. For example, Bayham is serving on a U.S. Forest Service task force that will examine potential outcomes of coronavirus on firefighters as fire season returns.

And along with department colleagues Becca Jablonski and Dawn Thilmany, Rebecca Clary, Rebecca Hill and Alexandra Hill, he is also serving on a Colorado Department of Agriculture-focused task force looking at effects of social distancing measures on food supply chain issues. CSU's vice president for engagement and extension, Blake Naughton, established the CSU Task Force on Colorado Food Supply to conduct research on several key areas: food access and security; designating food retail establishments as "essential services;" food supply chain workforce readiness; and consumer expenditure and farm market access.

Should schools have to close, enlist childcare workers as nannies for health workers

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More information: Link to interactive dashboard with child care needs by state: covid.yale.edu/resources/childcare/

Link to interactive dashboard with COVID-19 complication risk factors: foodsystems.colostate.edu/covi … ty-labor-force-risk/

Jude Bayham et al, Impact of school closures for COVID-19 on the US health-care workforce and net mortality: a modelling study, The Lancet Public Health (2020). DOI: 10.1016/S2468-2667(20)30082-7