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How it started, where it’s headed,
and how scientists are fighting back

© 2020 Scientific American

June 2020

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SRPEEPCOI ARLT||||||||||||||||||||||||||||||||||| EVOLUTION

2 4 THE CORONAVIRUS PANDEMIC 46 The Unexpected Origin of Fingers ON THE COVER
In a matter of weeks
26 Chasing Plagues A remarkable fossil shows that the digits the SARS-CoV-2 virus
in our hands evolved before vertebrates infected millions, kil­
A virologist crawled through bat caves to find the emerged from the water to colonize land. ling thousands and
origins of the SARS-CoV-2 virus. By Jane Qiu By John A. Long and Richard Cloutier bringing the global
economy to a halt.
32  Fast-Track Drugs ASTRONOMY Read our special
rep­­ ort on the origins
With no time to make treatments from scratch, 54 A Planet Is Born of the plague, the
scientists are searching for existing compounds human toll, and the
that reduce harm. By Michael Waldholz High-resolution imaging of circumstellar search for treatments
disks—the swirls of dust left behind after and a vaccine.
36 Frontline Trauma stars form—is revealing hidden planets and Illustration by
insights about how solar systems evolve. Richard Borge.
Stress from fighting COVID-19 poses an By Meredith A. MacGregor
unprecedented threat to health care workers.

38 How the Healers Feel 62 What Should Carbon Cost?

Interviews by Jillian Mock and Jen Schwartz Smart math, combined with fundamental
policy choices, can determine a practical
40 The Vaccine Quest tax that will drive down CO2 emissions.
By Gilbert E. Metcalf
Only genetic engineering can create a protec-
tive serum in months rather than years. CONSCIOUSNESS
B y Charles Schmidt
70 Tales of the Dying Brain
44 What Comes Next
A brush with death can leave a lasting
Large outbreaks of disease in the past suggest legacy in the mind—and may help us
how ­the current crisis might play out. understand how the brain functions in
B y Lydia Denworth extreme conditions. B y Christof Koch

Illustration by Richard Borge June 2020, ScientificAmerican.com  1

© 2020 Scientific American

4 From the Editor

6 Letters

8 Science Agenda

To prevent future pandemics, stop deforestation.
By the Editors

9 Forum

Leaders who belittle science during a global health
crisis are a danger to us all. By Ben Santer

10 Advances

A collision model shakes up Pluto. New strategy to
8 prevent tropical extinction. Lightweight vaccine-

delivery technology. A poultry domestication mystery.

20 Meter

The poetic landscape of boreal forests.
By  Jessica  Goodfellow

22 The Science of Health

As drug-resistant superbugs spread, researchers
are turning to viruses that kill bacteria.
By Claudia Wallis

76 Recommended

Women ran Britain’s most extraordinary World War I
hospital. Why innovation flourishes in freedom.
The fury of hurricanes. How Dr. Claire Weekes cracked
10 the anxiety code. By Andrea Gawrylewski

77 Observatory

How we can best quantify “small” benefits.
By Naomi Oreskes

78 Anti Gravity

Misinformation and miscalculation in the time
of the coronavirus. By Steve Mirsky

79 50, 100 & 150 Years Ago  B y Daniel C. Schlenoff

80 Graphic Science

Globe-trotting humans spread COVID-19
around the world. By Mark Fischetti and
77 Martin Krzywinski

Scientific American (ISSN 0036-8733), Volume 322, Number 6, June 2020, published monthly by Scientific American, a division of Springer Nature America, Inc., 1 New York Plaza, Suite 4600, New York, N.Y. 10004-1562. Periodicals
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2  Scientific American, June 2020

© 2020 Scientific American

FROM Curtis Brainard is acting editor in chief of Scientific American.
THE EDITOR Follow him on Twitter @cbrainard

Covering Other columns and departments in the issue focus on the
Coronavirus pandemic as well. Our editorial calls for ending deforestation
to reduce our exposure to the zoonotic viruses behind some of
Since I last sat down to write F rom the Editor a few short the world’s worst outbreaks (p age 8) . Graphic Science presents
weeks ago, the toll of the coronavirus pandemic has been stag- a stunning data visualization of the SARS-CoV-2 virus’s genet-
gering: at press time, more than 180,000 deaths globally and ic evolution as it spread around the globe (p age  80 ). There’s
countless lives upended. Most of the planet is still on lockdown. more, and all of our coronavirus coverage is freely available
At times it seems unreal, although it shouldn’t. Many public online at sciam.com/coronavirusoutbreak.
health exp­ erts warned for a long time that something like this
would happen without our taking precautionary measures. If you need relief from the plague beat (and we all do), turn
to the back half of the features section for a series of articles
The crisis reminds us that knowledge matters and throws that will carry you away to a land of awe and wonder. Astrono-
into stark relief the ways that science works slowly and assidu- mer Meredith  A. MacGregor describes how Chile’s ALMA tele-
ously, over decades of painstaking research in epidemiology scope has helped reveal detailed patterns in the debris disks
and virology, as well as urgently and frenetically, in the midst around stars where planets are forming ( page  54) . Paleontolo-
of tragedy and disaster, to help the world prepare for and gist John  A. Long and evolutionary biologist Richard Cloutier
respond to epidemics. That work is by no means perfect or com- explain how the discovery of an extraordinary 375-million-year-
plete, but it is our only hope to stop the suffering. old fossil overturned the conventional wisdom about when and
how the elements of human hands evolved in lobe-finned fish-
This month we lead with a special report that traces years of es ( page 46 ). And neuroscientist Christof Koch explores the bio-
study of coronaviruses to current efforts in biomedicine to halt logically mysterious commonality of near-death experiences
the pandemic. Beijing-based science writer Jane Qiu profiles and how res­­ earchers might uncover what is happening in the
the Chinese virologist who tracked down dozens of deadly SARS- mind when we see that bright light (p age  70 ).
like viruses in bat caves ( page 26 ). Reporters Michael Waldholz
and Charles Schmidt cover the race for COVID-19 treatments I want to thank the Scientific American team for its hard work
and a vaccine (p age 32 and p age 40, respectively). And journal- on this issue—it’s not easy to cover such an epic and rapidly
ists Jillian Mock and Lydia Denworth write about the lasting evolving situation in a monthly print magazine. I also want
impacts on frontline health workers and what comes next to thank all the health care workers, researchers and experts
(p age  36 a nd page  44, r espectively). who took the time to share their stories. It’s been a painful month,
and we owe a debt to everyone trying to bring this pandemic
to an end. 

BOARD OF ADVISERS Drew Endy Alison Gopnik Satyajit Mayor Daniela Rus
Professor of Bioengineering, Professor of Psychology and Senior Professor, Andrew (1956) and Erna Viterbi Professor
Leslie C. Aiello Stanford University Affiliate Professor of Philosophy, National Center for Biological Sciences, of Electrical Engineering and Computer
President, Wenner-Gren Foundation University of California, Berkeley Tata Institute of Fundamental Research Science and Director, CSAIL, M.I.T.
for Anthropological Research Nita A. Farahany
Professor of Law and Philosophy, Lene Vestergaard Hau John P. Moore Eugenie C. Scott
Robin E. Bell Director, Duke Initiative for Mallinckrodt Professor of Physics and Professor of Microbiology and Chair, Advisory Council,
Research Professor, Lamont-Doherty Science & Society, Duke University of Applied Physics, Harvard University Immunology, Weill Medical College National Center for Science Education
Earth Observatory, Columbia University of Cornell University
Edward W. Felten Hopi E. Hoekstra Terry Sejnowski
Emery N. Brown Director, Center for Information Alexander Agassiz Professor of Zoology, Priyamvada Natarajan Professor and Laboratory Head of
Edward Hood Taplin Professor Technology Policy, Princeton University Harvard University Professor of Astronomy and Physics, Computational Neurobiology Laboratory,
of Medical Engineering and of Yale University Salk Institute for Biological Studies
Computational Neuro­science, M.I.T., Jonathan Foley Ayana Elizabeth Johnson
and Warren M. Zapol Prof­essor of Executive Director, Project Drawdown Founder and CEO, Ocean Collectiv Donna J. Nelson Meg Urry
Anesthesia, Harvard Medical School Professor of Chemistry, Israel Munson Professor of Physics
Jennifer Francis Christof Koch University of Oklahoma and Astronomy, Yale University
Vinton G. Cerf Senior Scientist, Chief Scientist, MindScope Program,
Chief Internet Evangelist, Google Woods Hole Research Center Allen Institute for Brain Science Robert E. Palazzo Michael E. Webber
Dean, University of Alabama at Co-director, Clean Energy Incubator,
Emmanuelle Charpentier Kaigham J. Gabriel Morten L. Kringelbach Birmingham College of Arts and Sciences and Associate Professor,
Scientific Director, Max Planck Institute President and Chief Executive Officer, Associate Professor and Department of Mechanical Engineering,
for Infection Biology, and Founding Charles Stark Draper Laboratory Senior Research Fellow, The Queen’s Rosalind Picard University of Texas at Austin
and Acting Director, Max Planck Unit College, University of Oxford Professor and Director,
for the Science of Pathogens Harold “Skip” Garner Affective Computing, M.I.T. Media Lab George M. Whitesides
Executive Director and Professor, Primary Robert S. Langer Professor of Chemistry and Chemical
George M. Church Care Research Network and Center for David H. Koch Institute Professor, Carolyn Porco Biology, Harvard University
Director, Center for Computational Bioinformatics and Genetics, Edward Via Department of Chemical Engineering, Leader, Cassini Imaging Science Team,
Genetics, Harvard Medical School College of Osteopathic Medicine M.I.T. and Director, CICLOPS, Amie Wilkinson
Space Science Institute Professor of Mathematics,
Rita Colwell Michael S. Gazzaniga Meg Lowman University of Chicago
Distinguished University Professor, Director, Sage Center for the Study of Director and Founder, TREE Foundation, Lisa Randall
University of Maryland College Park Mind, University of California, Rachel Carson Fellow, Ludwig Maximilian Professor of Physics, Harvard University Anton Zeilinger
and Johns Hopkins Bloomberg School Santa Barbara University Munich, and Research Professor of Quantum Optics, Quantum
of Public Health Professor, University of Science Malaysia Martin Rees Nanophysics, Quantum Information,
Carlos Gershenson Astronomer Royal and Professor University of Vienna
Kate Crawford Research Professor, National John Maeda of Cosmology and Astrophysics,
Director of Research and Co-founder, Autonomous University of Mexico Global Head, Computational Design + Institute of Astronomy,
AI Now Institute, and Distinguished Inclusion, Automattic, Inc. University of Cambridge
Research Professor, New York University,
and Principal Researcher,
Microsoft Research New York City

4  Scientific American, June 2020 Illustration by Nick Higgins

© 2020 Scientific American



February 2020 “Legislative action released by electrolyzers during hydrogen
is required to help production, the system overall is unlikely
SURGICAL DISCRETION scientists who are to raise levels in the atmosphere.
As an M.D., I’d like to applaud Claudia Wal- highly vulnerable
lis’s review of the ISCHEMIA and CABANA to repressive actions SOCIAL BRAIN MAPS
trials of treatments for particular heart con- by state politicians In “The Brain’s Social Road Maps,” Matthew
ditions in “The Case for Less Heart Surgery” beholden to local Schafer and Daniela Schiller describe excit-
[The Science of Health]. As she says, those (or national) interests.” ing observations that the hippoc­ ampus, tra-
trials conclude that stenting or bypass sur- ditionally thought to be specialized for
gery for stable coronary artery disease—in john p. moore weill cornell medicine memory alone, may have cells used for so-
which coronary arteries are narrowed—and cial dynamics. We suggest that this arrange-
ablation for atrial fibrillation—in which the mote the fallacy that after finding a nar- ment would explain why many people with
heart beats irregularly—may help patients rowing in someone who is stable, even synesthesia, in which senses are mixed up,
feel better, but they won’t live longer. someone without symptoms, we can pre- may make remarks such as “December is a
vent a heart attack simply by stenting it. fat, stupid man with a limp, and he is in love
In fact, we physicians have been aware I’m glad that Scientific American holds it- with February, who is a jolly and mothering
of this concept for quite some time. A dif- self to a much higher standard. presence.” Curiously, in such cases, if names
ficulty we have is imparting it to our pa- for two nonsequential months are placed
tients. I can attest that they don’t feel com- Bradley J. Dibble next to each other, then two sets of emo-
fortable with the idea of treating a block- PACE Cardiology, Ontario tions start blending or clashing unless a line
age with medication alone. If they know is drawn between them, which stops the in-
there is an 80 percent narrowing in one of HYDROGEN POWER teraction. The sensory barrier becomes a
their heart arteries, they will feel better if In “The H2 Solution,” Peter Fairley discuss- conceptual-metaphorical one.
it’s “fixed” by stenting. But by cracking es how hydrogen could be utilized as part
open a stable narrowing, we would actual- of efforts to fully adopt renewable power. Calendar synesthesia, seen in 1 to 2 per-
ly increase the risk of an abrupt closure and He writes that “solar and wind energy cent of the population, may involve the neu-
would have to give those patients more po- would split a limitless resource—water—to ral circuitry the authors describe. The cal-
tent antiplatelet medications than aspirin create hydrogen for electricity.” But I ques- endar envisioned by people with this con-
while the lesion heals after the procedure. tion the term “limitless,” in view of freshwa- dition can take idiosyncratic shapes, with
ter shortages around the globe. Could the months set in specific fonts. Our mental cal-
The times that stents and bypasses are electrolyzers he describes use seawater? endar involves circuits in the left angular
g oing to prevent death is when patients gyrus, important for sequence discrimina-
have unstable lesions that are at risk of oc- Additionally, I wonder if scientists have tion and connected to the same hippocam-
clusion. That’s why these procedures do speculated whether or not the widespread pal place cell or grid cell via a band of fibers:
prevent catastrophes in high-risk patients production of renewable hydrogen would the inferior longitudinal fasciculus.
but not in stable ones, for whom the risk significantly increase the amount of oxy-
of abrupt artery closure is very low. gen in the atmosphere. We suggest that in calendar synesthe-
sia, these connections are strengthened to
There have been many cases in the past Edwinna Bernat S hepherdstown, W.Va. the point of resembling real images. For
where those in the media have helped pro- example, if a calendar is projected on ver-
FAIRLEY REPLIES: Readers are right to tical stripes, subjects see moiré interference
watch out for any new technology’s unin- at the fringes. If the stripes are tilted, they
tended consequences. Researchers’ calcula- see the calendar as tilted in the opposite di-
tions, however, indicate that a shift to wind rection. If they turn their head to the right,
and solar power—plus the electrolyzers re- memories of the calendar’s left side become
quired to convert some of their renewable inaccessible to them. Musical scales in the
energy to hydrogen—would use far less wa- Indian melakarta system, which are clas-
ter than today’s fossil-fuel power plants. sified into a spatial grid of 72 ragas, evoke
And some of the water used would be regen- highly distinctive and elaborate emotions
erated by fuel cells or turbines that turn and may also utilize the same map.
hydrogen back into electricity.
Vilayanur S. Ramachandran
The reactions in both devices produce Zeve Marcus
one molecule of water for every molecule of
hydrogen consumed. Those reactions also University of California, San Diego
consume oxygen, so even though oxygen is
I am mildly on the autistic spectrum, and
the article by Schafer and Schiller spoke to
me. I am fairly certain that people with au-
tism have different social maps (and not

6  Scientific American, June 2020

© 2020 Scientific American



Laura Helmuth

just interactions) from those who do not. I ACTING EDITOR IN CHIEF  Curtis Brainard COPY DIRECTOR  Maria-Christina Keller CREATIVE DIRECTOR  Michael Mrak
wonder if anyone is doing research on how
the neural circuitry that the authors discuss CHIEF FEATURES EDITOR  Seth Fletcher EDITORIAL CHIEF OPINION EDITOR  Michael D. Lemonick
could also play a role in autism—that is, CHIEF NEWS EDITOR  Dean Visser
whether we not only build different maps
but have a completely different way to “an- FEATURES
alyze” social relationships.
Alexander Duffy v ia e-mail SENIOR EDITOR, CHEMISTRY / POLICY / BIOLOGY  Josh Fischman SENIOR EDITOR, TECHNOLOGY / MIND  Jen Schwartz
When Schafer and Schiller mention that
“the brain has a knack for finding alterna- NEWS
tive routes,” I am reminded of construction
scheduling, in which those routes are the SENIOR EDITOR, MIND / BRAIN  Gary Stix ASSOCIATE EDITOR, SUSTAINABILITY  Andrea Thompson
many possible paths through the activities SENIOR EDITOR, SPACE / PHYSICS  Lee Billings ASSOCIATE EDITOR, HEALTH AND MEDICINE  Tanya Lewis
that have to be completed to finish a proj- ASSOCIATE EDITOR, TECHNOLOGY  Sophie Bushwick
ect. They can be shown on a diagram con- ASSISTANT NEWS EDITOR  Sarah Lewin Frasier
nected by arrows indicating which tasks can
be performed after one is finished. Arriving MULTIMEDIA
at a “critical path” in such a diagram re-
quires calculating the duration of every pos- SENIOR EDITOR, MULTIMEDIA  Jeffery DelViscio SENIOR EDITOR, MULTIMEDIA  Steve Mirsky
sible path and choosing the one that gets SENIOR EDITOR, AUDIENCE ENGAGEMENT  Sunya Bhutta SENIOR EDITOR, COLLECTIONS  Andrea Gawrylewski
the job done quickest. Before computers, a
good engineer, or a team of them, could fin- ART
ish complicated projects under budget and ART DIRECTOR  Jason Mischka SENIOR GRAPHICS EDITOR  Jen Christiansen
on schedule with a hand-drawn diagram. PHOTOGRAPHY EDITOR  Monica Bradley ART DIRECTOR, ONLINE  Ryan Reid
Terry Herlihy C hicago
SCIENCE SUPPRESSION SENIOR COPY EDITORS  Daniel C. Schlenoff, Aaron Shattuck, Angelique Rondeau
Chuck Hagel’s January 2020 article “Stop MANAGING PRODUCTION EDITOR  Richard Hunt PREPRESS AND QUALITY MANAGER  Silvia De Santis
Suppressing Science” [Forum] was a wel-
come read at a time when evidence-based CONTRIBUTORS
policy making is indeed under sustained
assault. Former secretary of defense Ha- EDITORS EMERITI  Mariette DiChristina, John Rennie
gel outlines federal legislation to protect EDITORIAL  Gareth Cook, Katherine Harmon Courage, Lydia Denworth,
national government employees and the
scientific process from politically motivat- Ferris Jabr, Anna Kuchment, Robin Lloyd, Melinda Wenner Moyer,
ed interference by the executive branch George Musser, Ricki L. Rusting, Dava Sobel, Claudia Wallis
and its friends. Let’s hope that new laws
in this area are indeed enacted by a future, ART  Edward Bell, Zoë Christie, Lawrence R. Gendron, Nick Higgins, Katie Peek, Beatrix Mahd Soltani
wiser administration.
Legislative action is also required, how-
ever, to help scientists who are highly vulner- SCIENTIFIC AMERICAN CUSTOM MEDIA
able to repressive actions by state politicians MANAGING EDITOR  Cliff Ransom CREATIVE DIRECTOR  Wojtek Urbanek
beholden to local (or national) interests. Em-
ployees of public universities or agencies are MULTIMEDIA EDITOR  Kris Fatsy MULTIMEDIA EDITOR  Ben Gershman
particularly at risk. One needs only to recall ENGAGEMENT EDITOR  Dharmesh Patel
climate scientist Michael Mann’s experienc-
es at the hands of Virginia’s attorney gener- PRESIDENT
al when Mann was employed at the Univer-
sity of Virginia and the harassment of seis- Dean Sanderson
mologist Austin Holland by the University EXECUTIVE VICE PRESIDENT  Michael Florek VICE PRESIDENT, COMMERCIAL  Andrew Douglas
of Oklahoma’s administration when he VICE PRESIDENT, MAGAZINES, EDITORIAL AND PUBLISHING   Stephen Pincock PUBLISHER AND VICE PRESIDENT  Jeremy A. Abbate
headed the state’s Geological Survey.
W eill Cornell Medicine and
Scientific American’s Board of Advisers PROGRAMMATIC PRODUCT MANAGER  Zoya Lysak


PRODUCT MANAGERS  Ian Kelly, John Murren




PRESS MANAGER  Sarah Hausman



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June 2020, ScientificAmerican.com 7

© 2020 Scientific American



To Stop Societies can take numerous steps to prevent the destruction.
Pandemics, Stop Eating less meat, which physicians say will improve our health
Deforestation anyway, will lessen demand for crops and pastures. Eating fewer
processed foods will reduce the demand for palm oil—also a major
Viruses are less likely to kill humans feedstock for biofuels—much of which is grown on land clear-cut
if we leave wild animal habitats intact from tropical rain forests. The need for land also will ease if nations
slow population growth—something that can happen in develop-
By the Editors ing nations only if women are given better education, equal social
SARS, Ebola a nd now SARS-CoV-2: all three of these highly infec- status with men and easy access to affordable contraceptives.
tious viruses have caused global panic since 2002—and all three
of them jumped to humans from wild animals that live in dense Producing more food per hectare can boost supply without the
tropical forests. need to clear more land. Developing crops that better resist drought
will help, especially as climate change brings longer, deeper
Three quarters of the emerging pathogens that infect humans droughts. In dry regions of Africa and elsewhere, agroforestry tech-
leaped from animals, many of them creatures in the forest habi- niques such as planting trees among farm fields can increase crop
yields. Reducing food waste could also vastly lessen the pressure
tats that we are slashing and burning to create land for crops, to grow more; 30 to 40 percent of all food produced is wasted.
including biofuel plants, and for mining and housing. The more
we clear, the more we come into contact with wildlife that carries As we implement these solutions, we can also find new out-
microbes well suited to kill us—and the more we concentrate those breaks earlier. Epidemiologists want to tiptoe into wild habitats
animals in smaller areas where they can swap infectious microbes, and test mammals known to carry coronaviruses—bats, rodents,
raising the chances of novel strains. Clearing land also reduces
biodiversity, and the species that survive are more likely to host badgers, civets, pangolins and monkeys—to map how
illnesses that can be transferred to humans. All these factors will the germs are moving. Public health officials could then
lead to more spillover of animal pathogens into people. test nearby humans. To be effective, though, this surveil-
lance must be widespread and well funded. In Septem-
Stopping deforestation will not only reduce our exposure to ber 2019, just months before the COVID-19 pandemic
new disasters but also tamp down the spread of a long list of oth- began, the U.S. Agency for International Development
er vicious diseases that have come from rain forest habitats—Zika, announced it would end funding for PREDICT, a 10-year
Nipah, malaria, cholera and HIV among them. A 2019 study found effort to hunt for threatening microbes that found more
that a 10  percent increase in deforestation would raise malaria than 1,100 unique viruses. usaid says it will launch a new
cases by 3.3 percent; that would be 7.4 million people worldwide. surveillance program; we urge it to supply enough mon-
Yet despite years of global outcry, deforestation still runs rampant. ey this time to cast a wider and stronger net.
An average of 28  million hectares of forest have been cut down
annually since 2016, and there is no sign of a slowdown. In the meantime, governments should prohibit the
sale of live wild animals in so-called wet markets, where
pathogens have repeatedly crossed over into humans.
The markets may be culturally important, but the risk
is too great. Governments must also crack down on ille-
gal wildlife trade, which can spread infectious agents
far and wide. In addition, we have to examine factory farms that
pack thousands of animals together—the source of the 2009 swine
flu outbreak that killed more than 10,000 people in the U.S. and
multitudes worldwide.
Ending deforestation and thwarting pandemics would address
six of the United Nations’ 17 Sustainable Development Goals: the
guarantee of healthy lives, zero hunger, gender equality, responsi-
ble consumption and production, sustainably managed land, and
climate action (intact tropical forests absorb carbon dioxide,
whereas burning them sends more CO2 into the atmosphere).
The COVID-19 pandemic is a catastrophe, but it can rivet our
attention on the enormous payoffs that humanity can achieve
by not overexploiting the natural world. Pandemic solutions are
sustainability solutions. 

Visit Scientific American on Facebook and Twitter
or send a letter to the editor: editors@sciam.com

8  Scientific American, June 2020 Illustration by Taylor Callery

© 2020 Scientific American

Ben Santer i s an atmospheric scientist and a member FORUM
of the U.S. National Academy of Sciences.

Failure to Lead

A U.S. president who belittles science
during a pandemic is a danger to us all

By Ben Santer

I was listening t o the comforting background hum of the old strategy in the middle of a global pandemic. No nation is
refrigerator in my rented apartment. The noise stopped sudden- safe from a microscopic agent that can hitch a ride on any
ly; the only sound left was the tinnitus ringing in my ears. From airplane, ship, train or car. Building effective international
my chair, I looked out through the sliding glass door. Wind and organizations and alliances is a far better way of surviving
rain animated the bright-yellow flannel bushes on the hillside. a global health crisis than going it alone.
California had just had the driest February on record, and the
flowered branches seemed to be stretching like fingers to catch The phrase “an abundance of caution” has become common-
the life-giving rainwater. place in the past few months. People use it when explaining their
decision to self-quarantine. But an abundance of caution should
I had been self-quarantined at home for a week. After returning have been exercised at the beginning of the pandemic. Detailed
from a climate change workshop in Washington, D.C., I came down plans for scientifically accurate messaging should have been
with a low-grade fever and a dry, hacking cough. On day five I was ready, along with strategies for national and international coor-
tested for the novel coronavirus and other microbes. After sever- dination of response efforts.
al anxious days I learned that I had a different infection—a seri-
ous influenza strain—and as I write this, I am slowly recovering. They were not ready. The capability to test tens of thousands
of citizens a day and to give hospital staffers basic safety gear
While sequestered, I thought a lot about how complex sys- should have been in place. It was not. Members of the Trump
tems respond to big perturbations. That is part of my job. As a administration should have corrected the president’s misstate-
climate scientist, I study the atmospheric and oceanic respons- ments on the seriousness of the coronavirus. Instead they large-
es to things such as massive volcanic eruptions, large changes in ly remained silent. After years of belittling and neglecting sci-
the sun’s energy output and a doubling of atmospheric carbon ence—most notably the science of climate change—Trump is
dioxide levels. The novel coronavirus is a major shock to complex suddenly discovering that science is imperative for human sur-
human systems of governance. Here are a few personal thoughts vival and perhaps even for his own political survival. Through
on lessons learned from the current situation. science, a vaccine will be developed for the novel coronavirus. If
this country invests in science now—and if we invest in the main-
LESSON 1: Scientific ignorance can be fatal—particularly tenance of strong global health systems—we will be better pre-
if it starts with the U.S. president and trickles down from pared for the next novel virus waiting out there. 
there. It was scientifically incorrect for Donald Trump to
dismiss the coronavirus as no worse than the seasonal flu, JOIN THE CONVERSATION ONLINE
as he did on February 26. It was incorrect to advise U.S. cit- Visit Scientific American on Facebook and Twitter
izens to engage in business as usual, which he did as late as or send a letter to the editor: editors@sciam.com
March 10. It was incorrect to imply, as he did in a press brief-
ing on March 19, that the malaria drugs hydroxychloroquine
and chloroquine are promising remedies for COVID-19—
something that has not been verified. Dissemination of such
inaccurate information helped to spread the novel corona-
virus in America faster by delaying the adoption of social
distancing. Ignorance served as a potent disease vector.

LESSON 2: A leader tells hard truths in times of crisis, not
falsehoods such as “Anybody that wants a test can get a
test,” as Trump said on March 6 at the Centers for Disease
Control and Prevention. A leader does not assume the
mantle of expertise in areas where he or she has none. A
leader accepts responsibility for personal and organiza-
tional failures. A leader cares more about saving lives than
about winning reelection.

LESSON 3: “America first” is a singularly poor survival

Illustration by Martin Gee June 2020, ScientificAmerican.com  9

© 2020 Scientific American


Sputnik Planitia, the left lobe of
Pluto’s “heart,” is one half of the
evidence for a massive collision.

10  Scientific American, June 2020

© 2020 Scientific American


• A whisklike device helps to analyze
contaminated water

• Two definitions of the foot square off
• Blood doping boosts an Antarctic fish’s

active lifestyle
• Deaths from opioid overdose may be

drastically underestimated



New simulation delves into potential
for a buried ocean on Pluto

Pluto’s heart-shaped Tombaugh Regio
c ould be considered the dwarf planet’s aes­
thetic highlight. This colossal, highly reflec­
tive geologic feature was captured with
beautiful clarity by nasa’s New Horizons
spacecraft during its 2015 flyby. The feature’s
elliptical western lobe, Sputnik Planitia,
which by recent estimates is more than 1,200
miles long, caught researchers’ attention: It
appears to be a “bowl” carved out by a mon­
umental ancient impact. And today it is filled
with young floes of churning nitrogen ice.

New Horizons did not get quite as good
a look at the other side of Pluto. But when it
had a peek, it did manage to spot an area on
the part of the globe exactly opposite Sput­
nik Planitia that looked like a jumbled jigsaw
of crevasses, mounds and pits. With no
clearly apparent formation mechanism, sci­
entists speculated on its origin.

Now research suggests the impact that
carved out Sputnik Planitia is to blame. Ac­­
cording to simulations replicating that cata­
clysm, it sent powerful seismic waves around
and through Pluto, tearing up the surface on
the opposite side. Crucially, the transmission
of those potent seismic waves—and the
resulting creation of that chaotic terrain’s
specific dimensions—would depend on
Pluto having a 93-mile-thick subsurface
ocean of liquid water, an idea scientists
have been considering for a while.

The work was presented virtually at the
Lunar and Planetary Science Conference in
March. This modeling is still in its early days,
and it has yet to be peer-reviewed. But con­

J O I N T H E C O N V E R S AT I O N O N L I N E Visit Scientific American on Facebook and Twitter

© 2020 Scientific American


necting impacts to distant geologic features the planet’s exact opposite side, or antipode, that transmits stress waves more slowly
to infer Pluto’s interior structure is “a really to a geologic pandemonium of shattered than other likely candidates. The difference
novel idea,” says James Tuttle Keane, a plan- rock and maddeningly undulating topogra- in sound speed between the core and ocean
etary scientist at nasa’s Jet Propulsion Labo- phy. “There’s nothing like it anywhere else would be low—a quirk of physics that allows
ratory, who was not involved with the study. on the body,” Radebaugh says. Researchers more seismic energy to move through the
long thought this rough terrain came from ocean toward the other side than it other-
If this method of simulated planetary seis- Caloris’s violent creation—just as the undu- wise could. This means that overall, a gar-
mology holds water, Pluto’s secrets may not lating land opposite Sputnik Planitia may gantuan amount of that energy is trained on
be the only ones extracted from afar, says have come from a similar impact on Pluto. Sputnik Planitia’s antipode, enough to make
Paul Byrne, a planetary geologist at North the mangled features seen by New Horizons.
Carolina State University, who was also not So, scientists wondered, why not re-
involved in the research. The concept could create Pluto’s seismology to find out? They Still, the spacecraft’s images of that half
be extended to all kinds of icy worlds and turned to the model iSALE, which simulates of Pluto have poor resolution compared with
satellites, from the moons of the solar sys- planetary-scale impacts and replicates the those of the Sputnik Planitia side, Byrne says,
tem’s ice giants to the frigid behemoths hid- physics of impact shocks. Adeene Denton, so it is not easy to work out precisely what
ing out in the Kuiper Belt. This research is a planetary geologist at Purdue University they are showing. “There’s a lot of weird
a reminder of the incalculable value of New and lead author of the new work, says she stuff on that far side of Pluto,” Keane says.
Horizons’s meet-and-greet with Pluto, says has “blown up Pluto countless times.” “And there are a lot of different ways that
Jani Radebaugh, a planetary scientist at you can imagine creating some of those odd
Brigham Young University, who was not The simulation that best replicates the patterns that we see.” One such possibility
involved with the work. “It’s amazing how dimensions of Sputnik Planitia and Pluto’s involves volatile ices of methane, carbon
we squeeze every little bit out of it,” she adds. mangled antipodal terrain involves a 250- dioxide and nitrogen that chew up Pluto’s
mile-wide projectile moving at 4,500 miles landscape as they fluctuate between gases
Sputnik Planitia’s location hints at a bur- per hour and crashing into the dwarf planet. and solids. They could also be responsible for
ied ocean on Pluto, but more evidence is In the model, as Sputnik Planitia is carved unusual terrain, including the mess opposite
needed to confirm its existence. Scientists out, a massive shock wave travels through Sputnik Planitia. (A recent, unrelated study
use robots to detect seismic waves traveling Pluto, followed by a deformation-causing also blames volatiles for creating the chaotic
through Earth, the moon and Mars. These stress wave whose movement depends on terrain antipodal to Mercury’s Caloris Basin.)
waves reflect, deflect and contort, depend- the speed of sound in the material in which
ing on what material they pass through— it travels. The stress wave traverses Pluto’s But if the new model is correct, it adds
and they paint a picture of a world’s subter- rocky core relatively quickly and moves credence to the idea that Pluto and its icy
ranean layers. But this is not possible on far- slowly through the body’s icy shell. It travels cousins elsewhere could have substantial
flung Pluto, which lacks robotic explorers. even more slowly through the 93-mile-thick subsurface oceans. Far from being merely
liquid-water ocean sandwiched in between. frozen-through snowballs, Denton says,
Help, as it happens, was hiding billions of “they could all host such incredible, rich geo-
miles away on Mercury. Its Caloris Basin, a In the simulation that best fits the data, logic histories.” — Robin George Andrews
roughly 950-mile-wide impact crater, lies on Pluto’s core is made of serpentine, a rock

C O N S E R VAT I O N Roehrdanz, a researcher with the nonprofit tion risk could fall by more than 50 percent.
organization Conservation International. These results could help inform United
Extinction Climate change is expected to continue Nations officials scheduled to meet this
altering existing habitats, forcing more year. Focused on conserving the world’s
Calculations suggest how to slash organisms to relocate or adapt. For this flora and fauna, the U.N. Convention on
risk for tropical species by half study, published in February in E cography, Biological Diversity has proposed conserv-
t he researchers looked at existing and future ing 30 percent of Earth’s land and oceans
Climate change and habitat loss a re two habitat ranges for 104,059 plants and ani- by 2030. Formal protection from develop-
huge threats to animal and plant survival, but mals in South America, Africa and Asia and ment could save vulnerable ecosystems
a new study shows how managing both fac- existing ranges for 185,160 more—the larg- and mitigate the effects of climate change.
tors could help prevent extinctions. Cutting est-ever compilation of such data. They then
greenhouse gas emissions and protecting modeled future extinction risk for those spe- The model does not, however, take into
more tropical land could reduce the proba- cies if certain percentages of the planet’s account how different species interact with
bility of species blinking out, called extinction tropical land were placed under protection one another and with the landscape. A
risk, by more than half, the research found. (around 17 percent is protected now). hummingbird may move to a new location,
but the plants it depends on may not, for
Scientists had not previously calculated The scientists calculated that with example. Still, says Rachael Gallagher, a
the combined benefits that limiting climate 30 percent protected, if greenhouse biologist at Australia’s Macquarie University
change and saving swaths of land could have gases were also curtailed—consistent in New South Wales, who was not involved
for so many species, says co-author Patrick with the aim of keeping global tempera- in the study, the paper “provides an evi-
ture rise below two degrees Celsius above dence base for those advocating to expand
preindustrial levels—the species’ extinc- the world’s protected areas.” —S usan Cosier

12  Scientific American, June 2020

© 2020 Scientific American

TECH taminants, and they often have too much

Water Wand variation in measurement to be useful, she

Cheap, simple device detects says. Her group’s device might be able to
heavy metals in water
provide remote communities and well
Municipal water c an be contaminated
by electronic waste and other sources Dunking the attachments in an acid solu- owners—who in the U.S. are responsible
of heavy metals—but collecting, chemical- tion releases the absorbed ions, which can
ly preserving and transporting samples then be measured. for their own water-quality monitoring—
to laboratories for testing is challenging for
remote communities. Unlike possibly contaminated water with a feasible alternative to transporting
samples, which are considered hazardous,
To streamline the process, Emily the device can be safely mailed to testing high-volume liquid samples over long dis-
Hanhauser, a mechanical engineer at the facilities. It can also yield results after two
Massachusetts Institute of Technology, and years of storage, its creators say. In experi- tances. A more advanced version of the
her colleagues created a low-tech sample- ments, the tool accurately reflected the
collection device that costs less than two amounts of copper, nickel, lead and cadmi- device could potentially measure large
dollars to make. It consists of a plastic han- um added to a variety of water samples,
dle tipped by propellerlike attachments the researchers reported in March in E nvi- clumps of contaminating metals as well,
made from polymer mesh, which contain ronmental Science and Technology.
small packets of absorbent resin beads that the researchers add.
attract heavy metal ions. Users stir the A detailed analysis of water quality ide-
device in water and then blot or air-dry it. ally would be performed near the source, “I think this could be a good diagnostic
eliminating the need for sample shipping
MELANIE GONICK Massachusetts Institute of Technology entirely, Hanhauser notes. But existing tool because of the low cost, good metal-
tools designed for that purpose cannot
measure small enough amounts of con- recovery numbers and superiority over

presence/absence tests,” says Siddhartha

Roy, an environmental engineer at Virginia

Tech, who studies the notorious drinking

water in Flint, Mich., and who was not

involved with the new study. “I can see

superior versions of the device being used

following contamination events for

specific metals.” — Rachel Crowell

MEDICINE suit each specific vaccine candidate and who was not involved in the study. She
provide a protective coating. “We’ve
Vaccine learned over time that the key to really sta- notes that each vaccine type would need
Transport bilizing whatever the film holds is to have it
intermixed with all the ingredients,” Croyle a custom formulation for future stages
A flexible film could deliver says, adding that the process is quick and
crucial medication uses affordable, standard benchtop equip- of development.
ment. “We really wanted to come up with
Vaccines may soon m ake their film debut. something that would be transferable to Finding partners to scale up manufac-
Led by pharmaceutics expert Maria A. developing countries.”
Croyle, researchers at the University of turing for clinical trials is the researchers’
Texas at Austin have developed a thin sheet Immunization programs depend heavi-
that preserves vaccines and other biological ly on keeping vaccines cold (two to eight most pressing hurdle, Croyle says. They
medicines for long periods without refriger- degrees Celsius) as they are transported,
ation. This means the carefully cooled vials sometimes over thousands of kilometers are also exploring packaging methods to
now used to ship vaccines could potentially to remote locations. Delivery can be diffi-
be replaced by lightweight, peelable films cult and costly, and transport disruptions keep their films stable up to 40 degrees C.
that can be mailed in an envelope and can render the vaccines ineffective.
stored on a shelf. Size is a major advantage of this plat-
But this new formulation can store live
Croyle’s laboratory began developing viruses, bacteria and antibodies for several form—a letter-sized sheet of the film can
the technology in 2007. Inspired by amber’s months at ambient temperatures (20
ability to preserve the DNA of insects and degrees C). In a new paper, published in carry more than 500 doses of vaccine,
other living things, the researchers set out March in S cience Advances, the scientists
to create their own version of the sub- show that the live viruses in one vaccine about 1⁄900 the weight of equivalent tradi-
stance by mixing together “a lot of sugar were preserved in the film even after 36
and a little bit of salt, much like hard can- months. They also find that a flu vaccine tional doses. By making it easier and
dy,” Croyle explains. The vaccine-contain- suspended in their film compares favorably
ing film is administered by mouth—sweet with a traditional flu shot. “The study dem- cheaper to ship and store vaccines effi-
news for many who dislike needles. onstrates early proof of concept for an
exciting platform for vaccine product ciently, Croyle says, the technology could
The film’s components are tailored to development,” says Lisa Rohan, a pharma-
cologist at the University of Pittsburgh, vastly improve immunization rates the

world over, particularly in middle- to low-

income countries. —H arini Barath

Illustration by Thomas Fuchs June 2020, ScientificAmerican.com 13

© 2020 Scientific American



Landing on the Right Foot

Federal agencies are eliminating a multistate disagreement
over a basic measurement unit’s length

International foot

U.S. survey foot

Wash. Not specified Me.
Ore. Idaho
Mont. N.D. Vt. N.H.
Wyo. Minn. Mass.
N.Y. R.I.
S.D. Wis.
Mich. Conn.
Neb. Iowa Pa. N.J.
Ill. Ohio Del.
Nev. Utah Ind. W. Va. Va. Md.
Calif. Kan. Mo.
Colo. Ky.

Okla. Ark. Tenn. N.C.
Ariz. N.M.
Hawaii Miss. Ala. Ga.

Alaska Tex. La.


Scientific American is a registered trademark of In 2023 every U.S. land surveyor w ill of a meter, has an unending decimal.) This SOURCE: NOAA’S NATIONAL GEODETIC SURVEY
Springer Nature America, Inc. ffiinally be on equal footing. One kind of means that anyone working in multiple
foot, speciffiically: the “international foot.” U.S. locations or with difffferent agencies
Scientific American is a registered trademark of These engineers have long measured land must keep careful track of which foot is in
Springer Nature America, Inc with two versions of the unit, depending use. A recent poll of 530 attendees of a
on which state they are in and whom they National Geodetic Survey Webinar, who
14  Scientiffiic American, June 2020 work for. To eliminate the resulting confu- were mostly surveyors, found that 62 per-
sion, surveyors will soon stop using what cent blamed confusion between the two
is called the “U.S. survey foot” and use feet for problems in their work.
only the international version.
Bungled math is common in trying to
The two are nearly identical—dividing interpret others’ measurements, says Brian
one by the other provides a ratio of Fisher, a registered land surveyor in Arizo-
0.999998. But over long distances, such na: “I’ve seen it dozens or hundreds of
minuscule difffferences add up and can times in my career.” Fortunately, he adds,
cause big problems. Every building in the “it’s not an error until you build it.” But
U.S. sits on speciffiic GPS coordinates, which Dennis notes that this does happen, citing
are typically rendered and documented in an engineer’s account of a building that
meters. When mapping property or con- was constructed near a landing strip—
struction plans, surveyors convert those and had to lose its top flfloor at the last min-
meters to feet. If they use an unexpected ute to avoid obscuring the planes’ glide
type of foot, future engineers referencing path, which had been calculated with a dif-
those maps might install or look for infra- fering type of foot.
structure in the wrong place.
The offifficial announcement of the
“It’s kind of a mess,” says Michael Den- impending change is slated for the end
nis, the National Geodetic Survey project of June, and the public has been given
manager overseeing the transition. Most a chance to weigh in on the mandate.
engineering projects in the U.S. have used Some people have expressed support;
the international foot since 1959, but land others warn it may cause even more con-
surveys—which map boundaries and infra- fusion, and a few suggest U.S. surveyors
structure locations—use whichever foot an just embrace the metric system. “We real-
organization or state wants. (The interna- ly wanted people to go metric,” Dennis
tional foot is exactly 0.3048 of a meter, says, “but that’s a difffferent kind of battle.”
whereas the U.S. survey foot, 1200/3937 —L eslie Nemo

Graphic by Amanda Montañez

© 2020 Scientific American

Bald notothens I
ANIMAL BEHAVIOR published in January in the J ournal of
Blood-Doping Experimental Biology. T
The scientists compared RBC levels in Join the nation’s
To remain active in frigid waters, largest association of
an Antarctic fish drastically samples collected from bald notothens freethinkers, atheists
adjusts blood oxygen and agnostics working
relaxing in glass tanks with those in sam-
Blood doping t o heighten performance to keep religion
is forbidden in professional sports. Athletes ples drawn from fish they “chased” using out of government.
can use this technique to fuel their muscles
with more oxygen-carrying red blood cells— a plastic tube. RBC levels were at 9 percent For a free sample of
for example, by receiving a transfusion. FFRF’s newspaper,
But many animals dope naturally: sheep, in the resting animals but 27 percent in the Freethought Today:
marine fishes and horses can boost their
blood’s capacity to carry oxygen by 16 to exercised ones, showing a 207 percent Call 1-800-335-4021
74 percent in physically demanding situa-
tions. Now a study shows that an Antarctic spike in the latter’s blood oxygen-carrying ffrf.us/reason
fish called the bald notothen can ramp up
its carrying capacity by more than 200 per- capacity. “No [other] fish we’ve seen can .
cent to pursue an active life in frigid waters.
more than double their RBCs or drop their FFRF is a 501(c)(3) educational charity.
Like most fishes native to Antarctica, Deductible for income tax purposes.
the bald notothen’s blood contains anti- numbers to such a low level when resting,”
freeze proteins that help it withstand June 2020, ScientificAmerican.com 15
extreme cold. But these proteins, along Axelsson says. This low level reduces strain
with red blood cells (RBCs), can make
blood viscous and hard to circulate. Some on the bald notothens’ heart, he adds.
Antarctic fishes adapt by eliminating RBCs
altogether, absorbing oxygen directly from The fish’s spleen stores RBCs, and the
the water via gills and skin as they passive-
ly await prey. Bald notothens, however, researchers found that to eject more into
actively swim below surface ice to chase
krill and other crustaceans while dodging the bloodstream, the organ contracts to
predators such as penguins and seals.
For this behavior, “you need to supply [more] weigh 41 percent less.
oxygen to the muscles,” says Michael
Axelsson, a cardiovascular physiologist at The enormous changes in RBC levels
the University of Gothenburg in Sweden
and co-author of the new study, which was initially surprised Gerald Kooyman, a

marine biologist at the Scripps Institution

of Oceanography, who was not involved in

the study. He notes, however, that these

animals have fewer blood cells to begin

with, so maintaining circulation with a tri-

pled RBC count is less difficult. If a diving

Weddell seal pushed its RBC levels from

40 to 90 percent, for instance, its blood

would be dangerously hard to pump.

Yet bald notothens do face trade-offs

for their ability. By attaching a probe to

each fish’s aorta, the scientists found blood

pressure was 12 percent higher and the

heart worked 30 percent harder in active

individuals. The heart can rest during quiet

PAULO OLIVEIRA Alamy times, but when bald notothens need to

exert themselves, Axelsson says, “these fish

have to live with the slightly higher conse-

quences of [more] RBCs because they need

more oxygen.” —P riyanka Runwal

© 2020 Scientific American


ANTHROPOLOGY a human-grown crop, suggesting that the

Tastes Like birds lived alongside people year-round—a
first step toward domestication. Barton says
New analysis ruffles the story
of poultry domestication Modern pheasant the process likely paralleled early chicken

Chickens are by far t he most numerous lished in February in Scientific Reports. domestication: wild birds started interacting
birds on the planet, with a population of Most archaeologists had assumed that
around 23 billion. But new research sug- closely with humans and eventually formed
gests that another species was once a bird bones found with those of pigs and
strong contender to become the world’s dogs, along with agricultural tools, at lasting, interdependent relationships with
favorite poultry: ancient bird remains in 8,000-year-old sites in northern China were
China have turned out to be not from the the earliest evidence of chicken domestica- them. True domestication, however, entails
first domesticated chickens, as researchers tion. But many wondered how red jungle
long assumed, but from pheasants. The fowl—known to be chickens’ wild ances- physical or genetic change brought about by
study further indicates that wild pheasants tors—could suddenly appear more than
lived side by side with people, shedding 1,000 miles from their native range in South- artificial human selection; the ancient pheas-
light on the early domestication process. east Asia. In 2015 researchers raised the pos-
sibility that the bones belonged to pheas- ant genomes match modern ones, so these
“It’s uncommon for us to have evidence ants, which are native to northern China.
of deer, for example, living with hunter- birds were still technically “wild.”
gatherers,” says Loukas Barton, an archae- For a definitive answer, Barton and his
ologist at California-based environmental colleagues analyzed the bones of eight birds Yu Dong, a geneticist at Shandong Uni-
consulting firm Dudek. “But in this case, found at Gansu Province’s 7,500-y­ ear-o­ ld
we see what otherwise is considered a Neolithic Dadiwan site that were previously versity in China, who was not involved in the
wild animal living in the human biome.” identified as chickens. Researchers at the
Barton is lead author on the study, pub- University of Oklahoma used two different research, says these “very important” find-
methods, including sequencing the full
mitochondrial genome, to genetically con- ings provide significant insight into the histo-
firm that the bones belonged to pheasants.
ry of domestication. She wonders, though,
Biochemistry tests revealed that these
pheasants subsisted on a diet heavy in millet, whether Neolithic people would have been

likely to welcome pheasants. “In many plac-

es nowadays,” Dong notes, “a net is put up in

fields to prevent birds from eating up crops.”

Barton says humans probably consid-

ered pheasants a good meat source. But

he suspects that pheasants’ intermittent

egg laying may be why the more consis- J MROCEK Getty Images

tent chicken was ultimately domesticated

instead—perhaps explaining, he says,

“why today we don’t eat Kentucky Fried

­Pheasant.” — Rachel Nuwer

EPIDEMIOLOGY mosquito, it reproduces, mixing and match- transmitted in a single mosquito bite.”
ing genes. Until now, the most efficient way The findings are consistent with what
All in One to study Plasmodium’s genetic diversity was
to grind up whole mosquitoes and sequence Dyann Wirth, an infectious disease re­­
Scientists track malaria-causing the mix. The new technique lets scientists searcher at Harvard University specializing
parasites in individual blood cells determine whether a patient’s particular in parasites, who was not involved in the
parasites were the product of reproduction new study, had suspected based on earlier
Malaria struck a n estimated 228 million within a single mosquito or were introduced research. She calls the work “an important
people worldwide in 2018. Yet questions separately by different ones. technical breakthrough that will allow
remain about how the mosquito-borne a much deeper understanding of malaria
malaria parasite, P lasmodium, infects The researchers collected blood from transmission and recombination.”
humans—and how antimalarial-drug-resis- patients at a hospital serving different vil-
tance genes spread. Different strains of lages in Malawi, then sequenced genomes This technique can also indicate where
the parasite can exchange genes with one of the parasites found in infected blood infections are coming from. When eradica-
another when they reproduce sexually cells. Based on the parasites’ intermingled tion efforts reduce malaria cases in a given
inside an individual mosquito, and the genomes, the researchers found that near- area, analyzing blood cells from those who
resulting mixed strains infect humans ly all the infections studied likely came still get sick can reveal if the infected mos-
through the mosquito’s bite. A new study from an individual bite. quitoes came from afar or if local elimina-
paints a detailed picture of how Plasmodium tion was incomplete, explains Edward
trades genes, and it finds that all the genetic “Using single-cell sequencing of para- Wenger, director of global health research
diversity within an actively infected human sites from whole populations of infected at the Institute for Disease Modeling in
host—up to 17 parasite strains—can come individuals, we could really start to see Bellevue, Wash., who was not involved
from just one bite. The work was published for the first time how people are getting in the study. The method could also help
in January in C ell Host and Microbe. infected with malaria,” says Ian Cheese- researchers track the proliferation of
man, a parasitologist at Texas Biomedical drug-resistance mutations. Finding these
Plasmodium spends part of its life cycle Research Institute and senior author of the mutations—­ and containing their spread—
in humans and part in mosquitoes. In the new study. “Sometimes absolutely stagger- is a critical public health strategy for preserv-
ing amounts of genetic diversity are being ing drugs’ e­ ffectiveness. —V iviane Callier

16  Scientific American, June 2020

© 2020 Scientific American

Hits Researchers report dinosaur footprints up to In a Leipzig waste site, scientists found a soil
1.25 meters long on the roof of a cave in France, bacterium that can break down components of
B y Sarah Lewin Frasier likely coming from a type of titanosaur. Geologic polyurethane—and survive the toxic chemicals
processes buried and shifted the shoreline released in the process.
footprints to the cave’s roof, 500 meters deep.

 U.S.   OMAN 
A hiker found two rusted, Daily growth rings on
unexploded bombs from a 70-million-year-old
1935 on the Mauna Loa fossilized mollusk indicate
volcano on Hawaii’s Big that Earth turned faster
Island. The bombs had at the time, squeezing 372
been intended to help days into each year. The
divert lava flflow during creature’s former habitat,
an eruption. a shallow seabed, is now
on a mountain in Oman.


A 20-year experiment revealed that cattle-grazing Seven new peacock spider species—including one with a

For more details, visit areas frequented by elephants store almost twice van Gogh S tarry Night –like design—were discovered among
jun2020/advances as much carbon as areas that bar the animals; crowd-sourced photographs from across the continent.

soil in these areas also has higher nutrient levels. The spiders are known for their vividly colored abdomens.

© 2020 Scientific American

June 2020, ScientificAmerican.com 17


PUBLIC HE ALTH Estimated Opioid Overdose Undercounts by State, 2016

Drug Tested Known opioid overdoses Additional estimated Unidentified overdoses Other overdoses
W. Va. opioid overdoses (dotted lines)
A new model shows opioid
deaths may be significantly D.C. Undercounts of opioid-related deaths
underreported Ohio stemmed from the failure of many
death certificates to specify the drugs
Opioids have been blamed f or the deaths Pa. associated with overdoses. Researchers
of at least 400,000 U.S. residents in the Md. estimated that the majority of these
past two decades—but research now N.H. unidentified overdoses involved opioids.
shows that number could be much higher. R.I. Looking at a snapshot of just 2016, in
Mass. terms of deaths per 100,000 people,
Researchers looked at data from the Ky. states such as Pennsylvania, Delaware,
Centers for Disease Control and Preven- Del. Indiana and Louisiana show some of the
tion on about 630,000 people who died Conn. largest differences between researchers’
of drug overdoses between 1999 and 2016. Me. estimates and reported numbers.
They separated the deaths into two cate- Tenn.
For the first category, they analyzed Mich.
how contributing causes of death (such as Mo.
injuries and heart problems) and personal Ind.
characteristics (such as age and gender) N. J.
correlated with opioid involvement. Vt.
They then used these analyses to calculate La.
the probability of opioid involvement Utah
for each unidentified drug overdose, and Okla.
they found that the number of opioid Ariz.
deaths is likely 28 percent higher than N.C.
generally reported.
The researchers also noticed that in Wis.
five states—Alabama, Indiana, Louisiana, N.Y.
Mississippi and Pennsylvania—the number S.C.
of apparent opioid deaths over the seven- Colo.
year period more than doubles after taking Alaska
into account their adjustments. Va.
“Opioid deaths serve as one of the main Wash.
measures of the opioid crisis, and if opioid Ala.
deaths are not counted accurately, the extent Hawaii
of the crisis can be severely misrepresented,” Idaho
says Elaine L. Hill, an applied microecono- Ga.
mist at the University of Rochester Medical Ark.
Center and study co-author. The findings Ore.
appeared online in February in A ddiction. Minn.
Hill says this research highlights “the Miss.
potential role of state-level medical exami- Mont.
nation systems and other policies in driv- Kan.
ing high rates of underreporting.” For N.D.
instance, a lack of detail in death certifi- Tex.
cates could relate to whether counties Iowa
have a coroner or medical examiner, the S.D.
study authors say. Either can declare cause Neb.
of death, notes Alina Denham, study co-
author and Ph.D. candidate at the Univer- 0 5 10 15 20 25 30 35 40 45 50
sity of Rochester. But not all coroners con- Deaths per 100,000
duct autopsies—so Denham says coroner-
based jurisdictions may be more likely to have missing information on particular level of specificity.” Because of that, he adds,
drugs’ involvement in overdoses. Most
counties in the five states with the highest overdose mortality statistics for opioids—
discrepancies have coroners.
and other drugs—can be misleading. Using
Robert Anderson, chief of the mortality
statistics branch of the National Center for calculations like the ones in this study, he
Health Statistics, who was not involved in
the study, says the research highlights what says, should help capture more accurate
his department has known for some time:
drugs are often not clearly identified in and geographically comparable opioid
drug-related deaths, and “there is substan-
tial variability by state and by county in the death estimates.

The researchers say they hope govern-

ment officials and other researchers will use

their new prediction model to calculate

estimates for future deaths and to reexam-

ine past data. — Jillian Kramer

18  Scientific American, June 2020 Graphic by Amanda Montañez

© 2020 Scientific American

METER Jessica Goodfellow, a teacher and editor living in Japan, is author
of the poetry collections Mendeleev’s Mandala, The Insomniac’s
Edited by Dava Sobel Weather Report, A Pilgrim’s Guide to Chaos in the Heartland and,
most recently, Whiteout. Her work has appeared in Best American
Poetry a nd other anthologies.

North of the Drunken Forest

Absent of taproot, the black spruce leans madly in which buried deep are layers of ancient volcanic ash,
where permafrost slumps into thermokarst. Who soot from fires primeval, banked bubbles of archaic air—
wouldn’t fall down soused when the ground beneath stories stored, frozen, in cerulean cerebral cortex, a vortex
began to melt, to buckle and sink? Who wouldn’t drink? stilled, which soon may spill. The polar ice, in stripes, remembers

In the boreal forests, in a landscape staggered what we weren’t here to recall, but as with all memory,
with lurching birches, ice is a memory, while farther what is buried in the blue yonder—if it escapes the icescape—
north, where glaciers begin to thin, ice is memory, could kill us. Deep memory is a danger zone. Ice is another
or the keeper of memories, a kind of collective mind nether. No wonder it numbs. No wonder it burns.

RAY BULSON Getty Images

20  Scientific American, June 2020

© 2020 Scientific American

THE SCIENCE Claudia Wallis is an award-winning science journalist whose
OF HEALTH work has appeared in the New York Times, Time, Fortune a nd the
N ew Republic. She was science editor at Time a nd managing editor
of Scientific American Mind.

Viruses Can Be numerous organisms on earth. And like guided missiles, each
Saviors, Too type has evolved to seek and destroy a specific type of bacteria.
Phage therapy has long been used in eastern Europe to battle infec-
As superbugs spread, researchers are tions, but after modern antibiotics arrived in the 1940s, it was
turning to viruses that kill bacteria largely ignored. Interest began to pick up in this century “because
the resistance issue was getting worse and worse,” says Vincent
By Claudia Wallis Fischetti, who heads the laboratory of bacterial pathogenesis and
immunology at the Rockefeller University. With modern tech-
This year the world awakened to the fact that the most power- niques, virologists can precisely match just the right phages to a
ful and sophisticated species on earth is tragically vulnerable to specific strain of superbug—with sometimes astonishing results.
the tiniest and most basic of creatures. Infectious disease spe-
cialists have been warning about this for decades. And the threat Tom Patterson, for example, was resurrected from an over-
comes not only from novel viruses, such as the one causing whelming Iraqibacter infection after his wife, Steffanie Strathdee,
COVID-19, that jump from animals to humans but also from an infectious disease epidemiologist, scoured the world for phag-
microbial monsters that we have helped to create through our es that might save him. The couple, both professors at the Univer-
cavalier use of antibiotics: treatment-resistant bacteria such as sity of California, San Diego, tell his story in their 2019 book The
MRSA (methicillin-resistant S taphylococcus aureus) and multi- Perfect Predator. Strathdee has since co-founded U.C.S.D.’s Center
drug-resistant A cinetobacter baumannii, s ometimes dubbed for Innovative Phage Applications and Therapeutics.
“Iraqi­bacter” because so many soldiers returning from Iraq were
infected with it. The World Health Organization has predicted For now phage therapy remains experimental. In most cases,
that deaths from resistant “superbugs” will rise from roughly it involves making custom cocktails of several phages shown to
700,000 a year today to nearly 10 million by 2050. be active in vitro against an individual patient’s bug. In Patterson’s
case, nine different phages were used in various cocktails inject-
But in a splendid irony, it may turn out that viruses, so often ed into his bloodstream multiple times a day over 18 weeks. Strath-
seen as nemeses, could be our saviors in fighting a host of killer dee envisions creating a library “with tens of thousands of phag-
infections. As the threat from drug-resistant bacteria has grown es, already purified, characterized and sequenced,” for medical
and the development of new antibiotics has stalled, researchers mixologists to draw on. Researchers are also developing premixed
have turned their attention to bacteriophages—literally, bacteria phage cocktails for some of the more common superbug strains.
eaters. Viruses in this class are believed to be the oldest and most
The effort that is furthest along, however, relies on a phage
enzyme called a lysin rather than on whole phages. After multi-
plying inside a bacterium, phages use lysins to break through the
cell wall of their host, instantly killing it. A purified lysin made
from a phage gene isolated in Fischetti’s lab was tested in a
phase 2 trial with 116 patients suffering from staph infections of
the blood or heart, including 43 with MRSA strains. The results
led the FDA to designate the lysin, known as exebacase, a “break-
through therapy,” meaning it will be fast-tracked for approval if
a phase 3 trial, now underway, bears out the findings.

The full phase  2 results have not been published, but “what
really grabbed a lot of attention was what we saw in the subgroup
with MRSA,” says Cara Cassino, chief medical officer at Contra-
Fect, the biotech firm developing exebacase. The infection was
cleared in 74 percent of MRSA patients given the lysin plus stan-
dard antibiotics but in only 31 percent of those who got antibiot-
ics plus a placebo. The respective mortality rates after 30 days
were 3.7  and 25  percent, Cassino says. Other lysin drugs are in
the pipeline at ContraFect and elsewhere.

Lysins work synergistically with standard antibiotics, Fischetti
says; they can pierce the walls of superbugs, enabling the drugs to
do their job. Lysins also clear up biofilms—slimy layers of bacte-
ria, carbohydrates and gunk—that cause lasting infections not
readily cured by antibiotics. Another advantage is specificity: lysins
kill their target without collateral damage to the microbiome.

Phage and lysin therapies still have a ways to go, but at a time
when much of the world is besieged by a virus, it’s good to know
that these tiny invaders may someday save us. 

22  Scientific American, June 2020 Illustration by Fatinha Ramos

© 2020 Scientific American



24  Scientific American, June 2020 Illustrations by Richard Borge

© 2020 Scientific American


By Jane Qiu

B y Michael Waldholz

B y Jillian Mock

B y Jillian Mock and Jen Schwartz

By Charles Schmidt

B y Lydia Denworth

June 2020, ScientificAmerican.com 25

© 2020 Scientific American


In 2004 S hi Zhengli IN CHINA TO  TRACK 
found a natural  THE  ORIGINS OF THE
reservoir of corona- FIRST SARS VIRUS AND
viruses in bat caves THE CURRENT PANDEMIC
in southern China.
Genetic analyses By Jane Qiu
show they have
leaped to people
several times, caus-
ing deadly diseases
such as COVID-19.
Increasing contact
between people
and wild animals
makes more
outbreaks likely.

26  Scientific American, June 2020

© 2020 Scientific American

June 2020, ScientificAmerican.com 27

© 2020 Scientific American

The mysterious patient samples arrived at the Wuhan Institute of
Virology at 7 p.m. on December 30, 2019. Moments later Shi Zhengli’s cell
phone rang. It was her boss, the institute’s director. The Wuhan Cen-
ter for Disease Control and Prevention had detected a novel corona-
virus in two hospital patients with atypical pneumonia, and it want-
ed Shi’s renowned laboratory to investigate. If the finding was
confirmed, the new pathogen could pose a serious public health
threat—because it belonged to the same family of viruses as the one that caused
severe acute respiratory syndrome (SARS), a disease that plagued 8,100 people
and killed nearly 800 of them be­t­ ween 2002 and 2003. “Drop whatever you are
doing and deal with it now,” she recalls the director saying.

Jane Qiu is Shi, a virologist who is often called China’s “bat “It’s incredibly important to pinpoint the source of infec-
an award-winning woman” by her colleagues because of her virus-hunt- tion and the chain of cross-species transmission,” says
science writer ing expeditions in bat caves over the past 16 years, disease ecologist Peter Daszak, president of EcoHealth
based in Beijing. walked out of the conference she was attending in Alliance, a New York City–based nonprofit re­s­ earch orga-
Shanghai and hopped on the next train back to Wuhan. nization that collaborates with researchers, such as Shi,
“I wondered if [the municipal health authority] got it in 30 countries in Asia, Africa and the Middle East to dis-
wrong,” she says. “I had never expected this kind of cover new viruses in wildlife. An equally important task,
thing to happen in Wuhan, in central China.” Her stud- he adds, is to hunt down other pathogens to “prevent
ies had shown that the southern, subtropical provinces similar incidents from happening again.”
of Guangdong, Guangxi and Yunnan have the greatest
risk of coronaviruses jumping to humans from ani- THE CAVES
mals—particularly bats, a known reservoir. If corona- To Shi, her first virus-discovery expedition felt like a
viruses were the culprit, she remembers thinking, vacation. On a breezy, sunny spring day in 2004, she
“Could they have come from our lab?” joined an international team of researchers to collect
samples from bat colonies in caves near Nanning, the
While Shi’s team at the Wuhan institute, an affiliate capital of Guangxi. Her inaugural cave was typical of
of the Chinese Academy of Sciences, raced to uncover the region: large, rich in limestone columns and—as a
the identity of the contagion—over the following week popular tourist destination—easily accessible. “It was
they connected the illness to the novel coronavirus that spellbinding,” Shi recalls. Milky-white stalactites hung
become known as SARS-CoV-2—the disease spread like from the ceiling like icicles, glistening with moisture.
wildfire. By April 20 more than 84,000 people in China
had been infected. About 80  percent of them lived in But the holidaylike atmosphere soon dissipated.
the province of Hubei, of which Wuhan is the capital, Many bats—including several insect-eating species of
and more than 4,600 had died. Outside of China, about horseshoe bats that are abundant in southern Asia—
2.4 million people across 210 or so countries and terri- roost in deep, narrow caves on steep terrain. Often
tories had caught the virus, and more than 169,000 had guided by tips from local villagers, Shi and her col-
perished from the disease it caused, COVID-19. leagues had to hike for hours to potential sites and
inch through tight rock crevasses on their stomachs.
Scientists have long warned that the rate of emer- And the flying mammals can be elusive. In one frus-
gence of new infectious diseases is accelerating—espe- trating week, the team explored more than 30 caves
cially in developing countries where high densities of and saw only a dozen bats.
people and animals increasingly mingle and move about.

28  Scientific American, June 2020

© 2020 Scientific American

These expeditions were part of the effort to catch the 1 OUTSIDE A BAT
culprit in the SARS outbreak, the first major epidemic CAVE i n China’s
of the 21st century. A Hong Kong team had reported 2 Guangxi province
that wildlife traders in Guangdong first caught the SARS in 2004, Shi Zhengli
coronavirus from civets, mongooselike mammals that Shi’s team used the antibody test to narrow down releases a fruit bat
are native to tropical and subtropical Asia and Africa. the list of locations and bat species to pursue in the after taking a blood
quest for genomic clues. After roaming mountainous sample ( 1 ). On the
Before SARS, the world had only an inkling of coro- terrain in most of China’s dozens of provinces, the same trip, a group
naviruses—so named because their spiky surface re­­ researchers turned their attention to one spot: Shitou of researchers
sembles a crown when seen under a microscope, says Cave, on the outskirts of Kunming, the capital of Yun- prepare bat blood
Linfa Wang, who directs the emerging infectious dis- nan, where they conducted intense sampling during samples that they
eases program at Singapore’s Duke-NUS Medical different seasons over five consecutive years. will screen for
School. Coronaviruses were mostly known for causing viruses and other
common colds. “The SARS outbreak was a game The efforts paid off. The pathogen hunters discov- pathogens ( 2 ).
changer,” Wang says. It was the first emergence of a ered hundreds of bat-borne coronaviruses with incred-
SHUYI ZHANG ( 1 and 2 ) deadly coronavirus with pandemic potential. The inci- ible genetic diversity. “The majority of them are harm-
dent helped to jump-start a global search for animal less,” Shi says. But dozens belong to the same group as
viruses that could find their way into humans. Shi was SARS. They can infect human lung cells in a petri dish
an early recruit of that effort, and both Daszak and and cause SARS-like diseases in mice.
Wang have been her long-term collaborators.
In Shitou Cave—where painstaking scrutiny has
With the SARS virus, just how the civets got it yielded a natural genetic library of bat-borne viruses—
remained a mystery. Two previous incidents were tell- the team discovered a coronavirus strain that came
ing: Australia’s 1994 Hendra virus infections, in which from horseshoe bats with a genomic sequence nearly
the contagion jumped from horses to humans, and 97 percent identical to the one found in civets in Guang-
Malaysia’s 1998 Nipah virus outbreak, in which it dong. The finding concluded a decade-long search for
moved from pigs to people. Wang found that both dis- the natural reservoir of the SARS coronavirus.
eases were caused by pathogens that originated in fruit-
eating bats. Horses and pigs were merely the interme-
diate hosts. Bats in the Guangdong market also con-
tained traces of the SARS virus, but many scientists
dismissed this as contamination. Wang, however,
thought bats might be the source.

In those first virus-hunting months in 2004, when-
ever Shi’s team located a bat cave, it would put a net
at the opening before dusk and then wait for the noc-
turnal creatures to venture out to feed for the night.
Once the bats were trapped, the researchers took blood
and saliva samples, as well as fecal swabs, often work-
ing into the small hours. After catching up on some
sleep, they would return to the cave in the morning to
collect urine and fecal pellets.

But sample after sample turned up no trace of
genetic material from coronaviruses. It was a heavy
blow. “Eight months of hard work seemed to have gone
down the drain,” Shi says. “We thought maybe bats had
nothing to do with SARS.” The scientists were about to
give up when a research group in a neighboring lab
handed them a diagnostic kit for testing antibodies pro-
duced by people with SARS.

There was no guarantee that the test would work
for bat antibodies, but Shi gave it a go anyway. “What
did we have to lose?” she says. The results exceeded
her expectations. Samples from three horseshoe bat
species contained antibodies to the SARS virus. “It was
a turning point for the project,” Shi says. The research-
ers learned that the presence of the coronavirus in
bats was ephemeral and seasonal—but an antibody
reaction could last from weeks to years. The diagnos-
tic kit, therefore, offered a valuable pointer as to how
to hunt down viral genomic sequences.

June 2020, ScientificAmerican.com 29

© 2020 Scientific American

IN YUNNAN A DANGEROUS MIX the cave for a year, the researchers discovered a diverse
In many bat dwellings S hi has sampled, including Shi- group of coronaviruses in six bat species. In many cases,
PROVINCE, CHINA, tou Cave, “constant mixing of different viruses creates multiple viral strains had infected a single animal, turn-
s cientists from a great opportunity for dangerous new pathogens to ing it into a flying factory for new viruses.
EcoHealth Alliance, emerge,” says Ralph Baric, a virologist at the Univer-
an international sity of North Carolina at Chapel Hill. In the vicinity of “The mine shaft stunk like hell,” says Shi, who, like
group that searches such viral melting pots, Shi says, “you don’t need to be her colleagues, went in wearing a protective mask and
for diseases that a wildlife trader to be infected.” clothing. “Bat guano, covered in fungus, littered the
can jump from cave.” Although the fungus turned out to be the patho-
animals to people, Near Shitou Cave, for example, many villages sprawl gen that had sickened the miners, she says it would
hunt for pathogens among the lush hillsides in a region known for its roses, have been only a matter of time before they caught the
in a bat cave. oranges, walnuts and hawthorn berries. In October coronaviruses if the mine had not been promptly shut.
2015 Shi’s team collected blood samples from more than
200 residents in four of those villages. It found that six With growing human populations increasingly
people, or nearly 3 percent, carried antibodies against encroaching on wildlife habitats, with unprecedented
SARS-like coronaviruses from bats—even though none changes in land use, with wildlife and livestock trans-
of them had handled wildlife or reported SARS-like or ported across countries and their products around
other pneumonialike symptoms. Only one had traveled the world, and with sharp increases in both domes-
outside of Yunnan prior to the sampling, and all said tic and international travel, pandemics of new dis-
they had seen bats flying in their village. eases are a mathematical near certainty. This had
been keeping Shi and many other researchers awake
Three years earlier Shi’s team had been called in to at night long before the mysterious samples landed
investigate the virus profile of a mine shaft in Yunnan’s at the Wuhan Institute of Virology on that ominous
mountainous Mojiang County—famous for its fer- evening last December.
mented Pu’er tea—where six miners suffered from
pneumonialike diseases and two died. After sampling More than a year ago Shi’s team published two
comprehensive reviews about coronaviruses in
E23G671 V iruses and Nature Reviews Microbiology. D rawing
evidence from her own studies—many of which were
published in top academic journals—and from others,
Shi and her co-authors warned of the risk of future
outbreaks of bat-borne coronaviruses.

On the train back to Wuhan on December 30 last year,
Shi and her colleagues discussed ways to immediately
start testing the patients’ samples. In the following
weeks—the most intense and the most stressful time of
her life—China’s bat woman felt she was fighting a bat-
tle in her worst nightmare, even though it was one she
had been preparing for over the past 16 years. Using a
technique called polymerase chain reaction, which can
detect a virus by amplifying its genetic material, the
team found that samples from five of seven patients
had genetic sequences present in all coronaviruses.

Shi instructed her group to repeat the tests and, at
the same time, sent the samples to another facility to
sequence the full viral genomes. Meanwhile she fran-
tically went through her own lab’s records from the
past few years to check for any mishandling of exper-
imental materials, especially during disposal. Shi
breathed a sigh of relief when the results came back:
none of the sequences matched those of the viruses her
team had sampled from bat caves. “That really took a
load off my mind,” she says. “I had not slept a wink
for  days.”

By January 7 the Wuhan team had determined that
the new virus had indeed caused the disease those
patients suffered—a conclusion based on results from
analyses using polymerase chain reaction, full genome
sequencing, antibody tests of blood samples and the
virus’s ability to infect human lung cells in a petri dish.

30  Scientific American, June 2020

© 2020 Scientific American

The genomic sequence of the virus, eventually named could not detect any known pathogen and called Shi

SARS-CoV-2, was 96 percent identical to that of a coro- for help. The cause of the illness—swine acute diarrhea

navirus the researchers had identified in horseshoe bats syndrome (SADS)—turned out to be a virus whose

in Yunnan. Their results appeared in a paper published genomic sequence was 98  percent identical to that of

online on February  3 in Nature. “ It’s crystal clear that a coronavirus found in horseshoe bats in a nearby cave.

bats, once again, are the natural reservoir,” says Daszak, “This is a serious cause for concern,” says Gregory

who was not involved in the study. Gray, an infectious disease epidemiologist at Duke

Since then, researchers have published more than University. Pigs and humans have very similar im­­

4,500 genomic sequences of the virus, showing that mune systems, making it easy for viruses to cross

samples around the world appear to

“share a common ancestor,” Baric says.

The data also point to a single introduc- “Constant mixing of different viruses 
tion into humans followed by sustained creates a great opportunity for 
human-to-human transmission, research- dangerous new pathogens to emerge.”
ers say.

Given that the virus seems fairly stable

initially and that many infected individuals —Ralph Baric U niversity of North Carolina at Chapel Hill
appear to have mild symptoms, scientists

suspect that the pathogen might have been

around for weeks or even months before

severe cases raised the alarm. “There might have been between the two species. Moreover, a team at Zheji-

mini outbreaks, but the viruses either burned out or ang University in the Chinese city of Hangzhou found

maintained low-level transmission before causing that the SADS virus could infect cells from many

havoc,” Baric says. Most animal-borne viruses reemerge organisms in a petri dish, including rodents, chick-

periodically, he adds, so “the Wuhan outbreak is by no ens, nonhuman primates and humans. Given the

means incidental.” scale of swine farming in many countries, such as

China and the U.S., Gray says, looking for novel coro-

MARKET FORCES naviruses in pigs should be a top priority.

To many, the region’s b urgeoning wildlife markets— The current outbreak follows several others during

which sell a wide range of animals such as bats, civets, the past three decades that have been caused by six dif-

pangolins, badgers and crocodiles—are perfect viral ferent bat-borne viruses: Hendra, Nipah, Marburg,

melting pots. Although humans could have caught the SARS-CoV, MERS-CoV (Middle East respiratory syn-

deadly virus from bats directly (according to several drome) and Ebola. But “the animals [themselves] are

studies, including those by Shi and her colleagues), not the problem,” Wang says. In fact, bats promote bio-

independent teams have suggested that pangolins may diversity and ecosystem health by eating insects and

have been an intermediate host. These teams have re­­ pollinating plants. “The problem arises when we get in

portedly uncovered SARS-CoV-2-like coronaviruses in contact with them,” he says.

pangolins that were seized in antismuggling operations

in southern China. TOWARD PREVENTION

On February 24 China announced a permanent ban When I spoke to Shi i n late February—two months into

on wildlife consumption and trade except for research, the epidemic and one month after the government

medicinal or display purposes—which will stamp out imposed severe movement restrictions in Wuhan, a

an industry worth $76  billion and put approximately megacity of 11 million—she said, laughing, that life felt

14 million people out of jobs, according to a 2017 report almost normal. “Maybe we are getting used to it. The

commissioned by the Chinese Academy of Engineer- worst days are certainly over.” The institute staffers had

ing. Some welcome the initiative, whereas others, such a special pass to travel from home to their lab, but they

as Daszak, worry that without efforts to change peo- could not go anywhere else. They had to subsist on

ple’s traditional beliefs or to provide alternative liveli- instant noodles during their long hours at work because

hoods, a blanket ban may simply push the business the institute’s canteen was closed.

underground. This could make disease detection even New revelations about the coronavirus kept com-

more challenging. “Eating wildlife has been part of the ing to light. The researchers discovered, for instance,

cultural tradition” in China for thousands of years, that the pathogen enters human lung cells by using

Daszak says. “It won’t change overnight.” a receptor called angiotensin-converting enzyme  2,

In any case, Shi says, “wildlife trade and consump- and they and other groups have since been screening

tion are only part of problem.” In late 2016 pigs across for drugs that can block it. Scientists are also rac­ing

four farms in Qingyuan County in Guangdong—60 to develop vaccines. In the long run, the Wuhan team

miles from the site where the SARS outbreak origi- plans to develop broad-spectrum vaccines and drugs

nated—suffered from acute vomiting and diarrhea, and against coronaviruses deemed risky to humans.

nearly 25,000 of the animals died. Local veterinarians “The Wuhan outbreak is a wake-up call,” Shi says.

June 2020, ScientificAmerican.com 31

© 2020 Scientific American

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isnhgoualgdrbiceutlhtuerfero. n“Ct hlinineaoifsthniostbtahtteleoanglyaihnsottsvpirouts,”esh. e Denison is not a prophet,
sayIsn, nreocteinngt dthecaatdoetshDerasmzakjoarnedmheirsgcionlgleeacgouneosmhaievse, but he is a virologist and an expert on the often
asuncahlyazesdInadpipar,oNxigmeartiaelayn5d00Bhrauzmil,aanrienafelscotiaotugsrdeiastearisseks. deadly coronavirus family, members of which
fromOnthce paosttencetinatluprya.tThhoegyenfosuanrde tmhatptpheedeomuet,rgsecniecne- also caused the SARS outbreak in 2002 and the
toifstnseawndpaptuhbolgicenhseatletnhdosfftiocihalaspcpaennriengupllaarcleyscwhehcekrefoar MERS eruption in 2012. It is a big viral group,
pdoensssiebpleopinufleactitoionnhsabsybaenenalcyhzaingibnlgotohdealannddsswcaapbes—abmy- and “we were pretty certain another one would
pblueisldfrinomg rloivaedsstoacnkd, fmroimnews,ilcduatntiinmgadlsotwhnatfaorreesfatsrmaned
ianntdentsriafydiendg,aagnridcufrltoumre.h“iCghhi-nraisiks nhoutmthaenopnolyphuolattsipoonts,”
hsuecshayass, fnaortminegrst,hmatinotehres,rvmilalajogreresmwehrgoinligveecnoenaormbaiets,
asuncdhpaesoIpnldeiaw, Nhoigheruiantanodr hBaranzdill,eawreiladlsloifea,t Ggrreaayt sriasyks..
ThiOs anpcperpooatcehn,tkianlopwanthaosg“eOnns earHeemalathp,p”eadimoustt,oscinietne-
tgirsatsteatnhde phuebaltich hmeanltahgoemceinatlsofcawnilrdelgifuel,alirvlyescthoecckkafnodr
poeosspilbel.e“Oinnfelycttihoenns cbaynawnaelcyaztinchg abnloooudtbanredakswbaebfosraemit-
tpulersnsfrionmtolaivnesetpoicdke,mfriocm,” hweilsdayasn,iamdadlisntghathtatrethfaersmtreadt-
aegnydctoruadldedp,oatenndtifarlolymsahvieghth-reishkuhnudmreadns opfobpiullliaotniosnosf
dsuocllharasssfuacrhmaenrse, pmidineemrsic, vciallnagceorsst.who live near bats,
andBpaecokpilne wWhuohhaunn,tworhheraendthleewloilcdklidfeo,wGnrawy saasyfsi.nTahlliys
laipftperdoaocnhA, kpnriol w8n, Cahsi“nOan’sebHatewalothm,”aanimissntootiinnteagcraelte-
tbhreathoerayltmhomoadn. Sagheemisednitsotrfewssileddlibfee,claivuessetosctko,riaensdfrpoemo-
tphlee. “IOntnelryntehtenancdanmwaejocratmcheadniaohutabvreearekpbeeafoterde iat ttuernnus-
ionutsosaunggepesidtieomnitch,”aht eSAsaRySs-,CaodVd-i2ngacthciadtetnhtealalyppleraokaechd
fcrooumldhpeortleanbt—iadlelyspsiatveeththeefahcutnthdarteidts goefnbeiltliicosnesqoufendcoel-
ldaoresssuncoht amnaetpcihdeamnyichcearnlcaobsht.ad previously studied.
OthBearcskciennWtisuthsaanr,ewqhueicrke thoedliosmckidssowthnewalalsegfiantiaollny.
“lSifhtei dleoandsAapwriol r8l,dC-chlainssa’lsabaotfwthoemhainghheasst dsteacnideadrdtso,”
Dreatsirzeakfrosamyst.he front line of virus-hunting expeditions.
“BuDt tehspeimteisthsieondimstuursbtagnocoe,nS,”hsiaiyssdSehteir, mwihnoedwitlol con-
tinue thoelreawdorreks.e“aTrchhepmroigssriaomnsm. “Wushtagtowoenh,”avseheunscaoyvs-.
“eWrehdatiswjueshtatvheeutnipcoovfearnedicisebjuesrtgt.”hDe taispzaokf ’asnteiacembehrags.”
Seshteimisapteladntnhiantgthtoerleaadreamnaotrieonthaal npr5o,0je0c0t tcoorsoysntaevmirautsi-
cstarlalyinsasmwpalietivnigrutsoebs eindbisactocvaevreesd, winithbamtsucghlowbaidlleyr. sSchoipies
panladnninintegnasintyatihoannalpprervoijoeucts taottseymstpemts.aDtiacaszllayks’samteapmle
vhiarsuseesstiimn abtaetdcathveast—thweirtehamreucmhowreidtehrasnco5p,0e0a0ndcoirnotnena-
vsirtyusthsatrnainshweraitteianmg ’tsopbrevdioisucsovaettreemdpintsb. ats globally.

“Bat-borne coronaviruses will cause more out-
breaks,” sShhei says with a tone of brooding certainty. “We
must fifind them before they ffiind us.” 

32  Scientifific American, June 2020

© 2020 Scientific American

enza medicine. When SARS-CoV-2 emerged, Painter’s
group immediately shifted focus. EIDD-2801, like rem-
desivir, inhibits the coronavirus’s self-copying opera-
tions, but it also works against virus variants with a
mutation that made them resistant to the Gilead drug.
In addition, EIDD-2801 is effective against a host of
other RNA viruses, so it could serve as a multipurpose
antiviral, much as some antibiotics can work against
a wide variety of bacteria. For COVID-19, says Wayne
Holman, co-founder of Miami-based Ridgeback Bio-
therapeutics, which has licensed the drug and is plan-
ning clinical trials, the goal is to have a pill that can
be taken by patients at home early in the course of the
disease to prevent it from progressing.

NIAID-RML BLOCKING INFECTION human airway cells. The virus locked onto the decoy EMERGING f rom
To stop SARS-CoV-2 f rom penetrating cells in the first and was marooned there. “We are blocking the door a cell, SARS-CoV-2
place, scientists are trying to develop antibodies that for the virus and, at the same time, protecting tissues,” virus particles (red
lock onto the viral protein that facilitates cell entry, a Penninger says. Apeiron is planning clinical trials circles) will create a
part of the virus known as the spike. Some of these later this year for APN01, which must be administered wider infection un­­­
neutralizing antibodies, made of a protein called in the hospital as an infusion to sick patients. less drugmakers find
immunoglobulin, may come from the blood of ways to block them.
patients who have already cleared the virus. Several OVERREACTIONS
medical centers, including Johns Hopkins Hospital In the sickest COVID-19 patients, a mass of mucuslike J ournalist Michael
and the Mayo Clinic, are harvesting blood plasma fluid accumulates in the lungs, preventing cells from Waldholz led a team
from survivors and screening it for antibodies. In a absorbing oxygen. These are the patients that need of reporters who were
technique known as convalescent therapy, doctors ventilators. The fluid buildup is the result of an over- awarded a Pulitzer Prize
then transfuse it into hospitalized patients with life- active immune response that involves a signaling in 1997 for their coverage
threatening acute respiratory distress. Early studies chemical called interleukin-6 (IL-6). Biotech compa- of AIDS. He lives in New
of a few such patients suggest the approach may nies, including Regeneron and Genentech, have man- York State’s Hudson Valley.
work—some patients’ symptoms improved, and lev- ufactured synthetic antibodies that can bind to IL-6
els of the virus in their bodies dropped—but the work and mute the call to action that it sends out.
is very preliminary.
Northwell Health, a large system of 23 hospitals
Takeda Pharmaceuticals, a Japanese firm, is also based in Long Island, N.Y., is one of more than a dozen
collecting plasma from recovered COVID-19 patients centers participating in clinical trials of the IL-6
to identify antibodies. In that plasma, the company is blockers, says Kevin Tracey, chief executive of the
identifying antibodies that show the most activity Feinstein Institutes for Medical Research, which is
against SARS-CoV-2. Using these antibodies as a tem- running the trials at Northwell sites. “The hospitals
plate, the Takeda researchers plan to synthesize a batch are being inundated with very sick patients suffering
of even more active versions to create a potent cock- from serious pneumonia and acute respiratory dis-
tail of infection inhibitors, says Chris Morabito, head tress,” Tracey says. “The IL-6 drugs have a plausible
of research and development of plasma-derived ther- mechanism of action. I’m optimistic they’ll work.”
apies. The therapy—TAK-888—might enter clinical tri-
als by year’s end, Morabito says; the number “888” rep- None of these approaches are cures. Denison says
resents “triple fortune” in Chinese. Several other the drugs under development may “reduce the sever-
drugmakers, including Regeneron and Vir Biotechnol- ity” of an advanced COVID-19 episode, especially if
ogy, are generating their own therapeutic antibodies they can be administered when initial symptoms—a
and say they will also be tested in patients this year. mild cough, muscle aches or slight fever—first arise.
In a hopeful future, a combination of various therapies
Another blockade strategy focuses on the cellular may be able to thwart the virus on several different
docking site that the virus uses. Josef Penninger, a fronts, the way a cocktail of antivirals can beat back
molecular biologist at the University of British Colum- an HIV/AIDS infection. By limiting symptoms, drugs
bia in Vancouver and founder of drug company may be able to keep some patients out of the hospital
Apeiron Biologics, is trying to lure the virus away and keep hospitalized patients off of ventilators. They
from a chemical receptor called ACE2 in the outer can serve as a bridge to survival as other scientists rush
wall of lung cells. The coronavirus spike protein binds to develop the real virus slayer: a vaccine. 
to this receptor. Several years ago Penninger’s lab syn-
thesized a decoy version of ACE2. In test-tube exper-
iments, the scientists found the synthetic molecule—
APN01—attracted coronaviruses away from real

June 2020, ScientificAmerican.com 35

© 2020 Scientific American

||||||||| ||||||||||||||||||||||||||
|||||||||||||||||||||||||||||||||||| |||||||||||||||||||||||||||||||||||
FRONTLINE RSEPPEOC IAL whelms the health care system. “Burnout is a chronic
RT response to health care conditions,” West says. “This is
an unprecedented acute crisis.”
TRAUMA |||||||||||||||||||||||||||||||||||
As the pandemic upends much of society, frontline
MEDICAL WORKERS health care workers are shouldering the burden of a sys-
ARE SOCIETY’S temic lack of preparation. In the U.S., a sluggish govern-
NEW HEROES. WHAT ment response, along with the bungled rollout of testing,
HAPPENS  WHEN  allowed the virus to spread widely. Years of running lean
 THE ACUTE CRISIS  operations left many hospitals without the resources to
 IS OVER?  quickly expand care. Global demand for personal protec-
tive equipment (PPE) and ventilators made these crucial
By Jillian Mock supplies scarce. Backup stockpiles proved too small, and
efforts to bolster supplies were uncoordinated or, worse,
After his roughest days in a New York City IN BRIEF forced hospitals and jurisdictions to compete with one
emergency room, physician Matthew Bai another. Now ERs in hard-hit areas struggle to keep up
feels his whole body relax when he sees his Health care workers with a flood of critically ill patients. Staff in eerily quiet
wife and 17-month-old daughter. “My light a re not just treating hospitals elsewhere look on, wondering if the virus will
at the end of the tunnel is going home to a flood of critically overwhelm them next. Nurses facilitate final phone calls
family,” Bai says. When Manhattan’s Mount Sinai Hos- ill patients during between the dying and their loved ones who are barred
pital started to overflow with C­ OVID-19 patients in late the pandemic. from entry. As morgues overflow, refrigerated trucks
March, however, Bai and his wife decided she should They are risking arrive to house the bodies.
take their toddler and stay with her parents in New Jer- their own health,
sey. The risk of spreading the virus to his family was witnessing higher “Our health care professionals are seeing incredibly
too great. Now Bai confronts a daily cascade of patients rates of death and sick people in what is really a tidal wave washing over
who are struggling to breathe, in an ER busier than he experiencing break- them, and they are leaning into that work because it’s
has ever witnessed it. On his mind, always, is whether downs of protocol what we do,” West says. But leaning into extreme uncer-
he will be able to keep his staff safe. All doctors have and support. tainty for weeks and months on end could have signifi-
bad shifts, but now those days repeat, piling up. At These acute stresses cant impacts on their mental well-being. More than any
night, virtual story time with his daughter is nowhere could lead to mental other group, they are in danger of getting sick from the
as soothing as the real thing. “I honestly have no idea health issues, yet constant exposure to SARS-CoV-2. As of April, the virus
how I feel,” Bai says. “I go to work, and at the end of the therapeutic support has infected more than 9,000 health care workers in the
day, I go to sleep. I have no time to digest any of this.” is lacking. U.S. and killed 27, according to the Centers for Disease
Control and Prevention. Hundreds of clinicians have died
Medicine is a stressful profession under normal cir- worldwide. Like Bai, many worry about spreading the
cumstances. The physical demands, psychological strain disease to their patients and loved ones; young medical
and ineffective work processes can lead to burnout, a residents are advising one another to write living wills.
condition that affects up to 50  percent of physicians in Some hospitals have muzzled their staffers, citing con-
the U.S., says Colin West, an internist who has studied cerns over the spread of misinformation and patient pri-
physician well-being at the Mayo Clinic for more than 15 vacy; around the world, clinicians who have spoken out
years. A 2018 review in the journal Cureus described it about the resource shortages or shared their experienc-
as “a combination of exhaustion, cynicism, and perceived es have been reprimanded or fired by their institutions.
inefficacy.” Burned-out clinicians are more likely to quit Many experts predict that, taken together, these traumat-
their jobs. Their patients may have worse outcomes. Yet ic effects of the pandemic will reverberate long after the
burnout cannot capture what doctors, nurses, paramed- virus itself is contained.
ics and others are experiencing as coronavirus over-
Trauma is often associated with something overtly
violent, such as a car accident or a shooting. But Dutch
philosopher Ciano Aydin describes a situation as trau-
matic when it “violates” familiar expectations about
someone’s life and world, sending them into a “state of
extreme confusion and uncertainty.” In the case of this
pandemic, prolonged uncertainty is compounded by the
moral anguish health care professionals face when they
do not have adequate resources to treat critically ill
patients, says Wendy Dean, a psychiatrist and co-founder
of the nonprofit Moral Injury of Healthcare.

Moral injury, a term borrowed from the military,
occurs when a person does something that goes against
his or her deeply held moral beliefs, Dean says. In med-
icine, it can occur when the business side of health care
hinders a physician’s ability to care for patients; for

36  Scientific American, June 2020

© 2020 Scientific American

instance, if there are not enough ventilators for the num- Jillian Mock i s a nurses during the height of the ­COVID-19 pandemic in
ber of C­ OVID-19 patients who need them. Physicians are freelance science China found that about 50  percent of respondents
not used to doing triage, to choosing who gets lifesaving journalist based in reported symptoms of depression, 44  percent reported
support and who does not, explains G. Richard Holt, an New York City. She symptoms of anxiety and 34 percent reported insomnia.
otolaryngologist and bioethicist at the University of Tex- writes about the Medical professionals are already at risk for many of
as Health Science Center at San Antonio. “We’re trained environment, climate these conditions at baseline—medical occupations have
in treating one patient at a time, but in the worst of an change and health among the highest rates of suicide—yet they are typical-
epidemic, you have to think about the greatest good for care, and her work has ly unlikely to seek help, Gold says. Most do not have the
the greatest number,” Holt says. Studies in soldiers sug- appeared in the N ew time or flexibility to go see a therapist during a standard
gest moral injury impedes normal emotional, psycho- York Times, Huffington nine-to-five workday, she notes, and the stigma still
logical and social functioning and often occurs in peo- Post and Discover, attached to psychological problems leads many to suffer
ple with post-traumatic stress disorder. “I think the real a mong others. silently. “We have never had a mental health system that
reckoning is going to come when this is over,” Dean says. could support the needs of the population in general, let
alone the population that will now be in need,” Gold says.
The emotional toll of C­ OVID-19 is tricky to predict.
During a natural disaster, medical professionals often Institutions such as UNC Health in North Carolina
deliver care after the immediate threat has passed, and have expanded therapy options for providers with tele-
those providers are able to go home and decompress at health and more flexible scheduling, as well as set up
the end of an upsetting day, says Joshua Morganstein, a support hotline. In the U.K., the ­COVID Trauma
chair of the American Psychiatric Association’s Commit- Response Working Group provides guidance, based on
tee on the Psychiatric Dimensions of Disaster. When you trauma psychology research, for proactive interventions.
are worried about bringing the disaster home with you, The right support can even foster resilience. “Some peo-
no place is safe. Health care workers are grappling with ple will find they experience a sense of an increase in
the upheaval of social and economic life along with the their own confidence or ability to manage future stress-
rest of us; they are exposed to the constant noise of grim ors,” says Morganstein, describing a process called post-
news. Some are tuning out coronavirus coverage as a traumatic growth.
coping mechanism. “We have to figure out what our reac-
tion would have looked like pre-iPhone,” says Suneel While these efforts are a start, Gold emphasizes that
Dhand, an internist who works at hospitals in Massa- expanded mental health support needs to be ongoing
chusetts. “I’m concerned about all the people absorbing and wide in scope, addressing systemic problems such
so much doom and gloom through social media.” as a nationwide mental health care professional short-
age and regulatory hurdles that limit telemedicine ser-
Jessica Gold, a psychiatrist at the Washington Uni- vices. Teletherapy, meditation apps and other virtual
versity School of Medicine in St. Louis, and other health services have already made inroads with the pop-
experts believe health care workers as a group could ulation at large in the past few months, and Gold and
develop high rates of anxiety, depression, substance use other therapists see it as a crucial tool for reaching health
issues, acute stress and, eventually, post-traumatic care workers as well.
stress as a result of what they are experiencing on the
pandemic front lines. Because this event is unprece- In cities across the world, people in lockdown have
dented, Gold worries the psychological damages will gathered at their windows to clap and cheer for essen-
be unprecedented, too. Data from other out- tial workers every evening. In New York, Bai reports that
breaks, while limited, support these con- local restaurants send a steady stream of food to the hos-
cerns. A small study of health care pital and that friends and strangers reach out with mes-
workers during the 2003 SARS out- sages of appreciation. All of this boosts morale immense-
break, for example, found that
89 percent of workers at high risk ly, Bai says. But the hero worship of health care
of contracting the virus report- workers only goes so far to protect them from
ed negative psychological effects. mental anguish. Like soldiers coming back
Another study found SARS- from deployment, it will take time for
related fear was correlated with health care professionals to process and
symptoms of PTSD. heal, Dean says. When the acute med-
ical crisis ends, a mental health
One survey of 1,257 physicians and crisis could emerge. This time
we need to be ready. 

June 2020, ScientificAmerican.com 37

© 2020 Scientific American

HOW THE Frontline clinicians h ave become the face of our pandemic. They repre-
HEALERS FEEL sent the best of humanity, rising to treat critically ill patients, as well as
the collateral damage from America’s fragile health care system and dis-
Interviews by ordered government response. Scientific American asked doctors, nurses
Jillian Mock and Jen Schwartz and respiratory therapists working in hospitals across the country how
they were coping with fear, processing grief and tending to their own
well-being. Interviews were conducted in late March and early April, as
C­ OVID-19 was rapidly upending life in the U.S. These essays reflect that
period of extreme uncertainty; they have been edited and condensed. 

ANA DELGADO to supporting the health and wellness of their
community. When you actually become a
Nurse Midwife and Clinical Professor provider, you’re thrust into this system that
San Francisco, Calif. is not really set up to promote health and
There was a lot of talk early on about how wellness, and you’re constantly confronted
this crisis was going to bring us all together. with this discrepancy. The pandemic makes
But what it has clarified for me is that we’re these issues worse, and it’s painful to wit-
not actually all in this together. It has laid ness. That’s not burnout, it’s a deep moral
bare what most reproductive justice advo- injury that people are experiencing.
cates already knew: inequity and racism
have always been around. I work at the Yes, I have to go work in the clinic and be
county hospital. The impact of shelter in exposed to people who might be COVID-
place has been stark for my pregnant positive, and that’s scary. But as a midwife,
patients, many of whom are undocumented I still get to lay my hands on people, to
and were already living paycheck to pay- touch and be with people on a daily basis.
check, and now are unemployed. A patient That’s part of my antidote. I struggle a bit
came in yesterday and burst into tears from with the hero worship of health care work-
her desperation. I feel extremely over- ers that’s going on. I want to be recognized
whelmed by the need. for my hard work, but I feel like it will swing
back to the other side, to mistrust and lack
There are a lot of injustices that we as cli- of support. That extreme exists because we
nicians are aware of and feel powerless to do don’t have a true public health network in
much about. People call this “burnout,” but this country, a model for developing healers
one of my colleagues talks about how that from our communities where there’s a sense
seems associated with self-blame, like you of trust. If that existed, everything would be
got something wrong. Most people go into different right now.
health care because of a deep commitment


Emergency Room Nurse Emergency Room
Dallas, Tex. Physician
In late March I was running a low-grade fever and had to self-isolate at my New York City
house for several days before my C­ OVID test came back negative. It was so I honestly have no idea
hard to stay away from my family and even harder to stay away from my work, how I feel. I don’t have
which I love. It felt like punishment, like I was losing my time to digest any of this.
mind. I’ll admit that I was drinking more than I ever do. I go to work, and then I go
In early April I decided to start staying in a hotel so as to sleep. Training in emer-
not to accidentally bring the virus home to my hus- gency medicine in New
band and two kids, who could also spread it to my York, with the speed and
immunocompromised dad, who helps with child number of patients, probably prepared me somewhat for
care. For me, the hardest part has been the isolation. what’s happening now. But nothing can prepare you for an
I’ve had an eerie sense of calm and peace about event of this magnitude. Everything is in flux. The upside is
all of this up until now, but recently I’ve started realizing the level of flexibility that’s possible in a hospital.
to feel something inside that is not me. I I’m seeing new faces in the ER all the time—nurses and
think it’s the separation, the loneliness of doctors from other departments, even surgeons, OBs and
keeping everyone at arm’s length. Some- people flying in from all over the country. In the back of my
times I get in the car, blast music and just head I’m constantly thinking, Can we manage our resourc-
go. I ran out of gas on a joy ride last week. es and keep our staff healthy for however long this lasts?

38  Scientific American, June 2020

© 2020 Scientific American


Float Pool Nurse Pulmonary Critical Care Physician and
Minneapolis, Minn. Associate Professor
You can never really be fully prepared for a pandemic. Thankfully, nurs- Boston, Mass.
ing is never routine, so we adapt quickly. I’m a float pool nurse, which For providers, there’s a really complex psychology to all
means I work on almost every unit in my hospital. I rarely feel intimi- this. Everyone realizes the importance of what they’re
dated by something new. But many of my co-workers have been dis- doing but doesn’t want to be the next person felled by
placed and are now working in unfamiliar areas or jobs, creating chaos ­COVID-19. You’re grappling with fear of the unknown
and stress. I’ve noticed the most tension on the new ­COVID rule-out and your call to duty. My wife, who is also a doctor, and
floors. Many staff members are scared to even enter the unit and act I have been at this game for longer than we care to admit,
like anyone working there is dirty. Patients have commented on how and we’ve never been in a situation where there was
they feel like a burden. Nurses working on these floors are teaching a real fear of interacting with patients like there is now.
everyone who enters a patient’s room how to properly put on and take
off our protective wear, and I have In mid-March I was three days into a rotation in the
been on the receiving end of many medical intensive care unit, ramping up for the inevitable
eye rolls and rude body language surge, when it was decided that those of us 60 and older
when all I was doing was trying would be pulled from clinical duty because of our higher
to help. Fear of the unknown is risk of dying from C­ OVID-19 infection. Now I have young-
certainly putting people on edge. er colleagues taking on a huge amount of work, and all of
I’m coping by just allowing myself them have young families. There’s a significant element
to leave work at work. My dog of guilt in not contributing. We ancients are currently fig-
has gotten more walks in the uring out how we can provide services to lighten their
past few weeks than the whole burden. It’s a nice gesture, but it’s a complicated process.
year combined.

PATTI MARSHALL GILPIN health care is at the top of their game, impro-
vising equipment, seeking out knowledge.
Respiratory Therapy Navigator I’ve watched transporters take patients from
Louisville, Ky. one place to another, interacting with them,
I educate patients with chronic lung disease. being so optimistic when there’s this palpable
My role right now seems a little silly; I can’t dread all over the hospital. I’ve seen amazing
educate people about something we don’t courage when staff have to do CPR on one of
understand. Worst-case scenario, I’ll go these patients, no hesitation when you have
back to doing the critical care with the ther- to intubate. But when it’s over? My co-work-
apists who are in the trenches. When you ers come into my office to vent and cry; some
read about what’s happening in New York talk about problems with anxiety. When my
and other areas on social media, it’s very shift ends, what do I do with this crap I’ve
difficult not to be scared. There’s a constant been carrying around all day, the things that
undercurrent of bracing for that potential happened, the things that could happen
surge. This huge push to ventilate more than tomorrow? You can’t even name it. Then
one person on a single machine? Yeah, you go home, and you can’t have your typical
you should never do that. So we’re getting social release because you fear contaminat-
support from each other about how we’d ing your loved ones. Worrying that I’m
handle having to do the wrong thing. going to spread this is the worst feeling of all.

It’s humbling to see how everyone in

Illustrations by Ina Stanimirova June 2020, ScientificAmerican.com 39

© 2020 Scientific American

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||Within days his laboratory and dozens of others
around the world started designing vaccines that they
SRPEEPCOI ARLT hoped could protect billions of people against the
SARS-CoV-2 virus, the biggest challenge to global health
THE VACCINE and prosperity since World War II. By early April almost
QUEST 80 companies and institutes in 19 countries were work-
ing on vaccines, most gene-based instead of using tra-
 ONLY GENETIC  ditional approaches, such as those that have been
 ENGINEERING  employed in influenza vaccines for more than 70 years.
CAN CREATE The labs predicted that a commercial vaccine could be
A PROTECTIVE available for emergency or compassionate use by early
SERUM IN 2021—incredibly fast, given that vaccines to brand-new
MONTHS RATHER pathogens have taken a decade to be perfected and
THAN YEARS deployed. Even the Ebola vaccine, which was fast-
tracked, took five years to reach widespread trials. If
By Charles Schmidt Barouch and his counterparts can offer a safe, effective
concoction in a year, “it will be the fastest vaccine devel-
On January 10, when Chinese opment in history,” he says.
researchers published the genome
of a mysterious, fast-spreading, That is a big “if,” however. Although labs have cre-
virus, it confirmed Dan Barouch’s ated several gene-based vaccines for other viruses, not
greatest worry. The genome was one has been commercialized for a human illness.
similar to that of the coronavirus
that caused the 2003 SARS out- A conventional vaccine injected into the body
break, yet it also had striking differences. “I realized inserts select pieces of a virus in cells near the injection
immediately that no one would be immune to it,” site. The immune system recognizes molecules on these
pieces, called antigens, as threats and reacts by making
says Barouch, director of virology and vaccine research antibodies, molecules that can find the virus anywhere
at Beth Israel Deaconess Medical Center in Boston. in the body and neutralize it. Once this dress rehears-
al happens, the immune system remembers how to
quash the invaders, so it can stop a future infection.

The established approach is to grow weakened
viruses in chicken eggs—or more recently in mamma-
lian or insect cells—and extract the desired pieces. The
process can take four to six months to get the right anti-
gens for familiar viruses that change every year, such
as influenza. It can take multiple attempts over years
for a new germ. That is far too slow to combat a virus
that has already spread to pandemic proportions.

Instead labs are turning to gene-based vaccines. Sci-
entists use information from the genome of the virus to
create a blueprint of select antigens. The blueprint is
made of DNA or RNA—molecules that hold genetic
instructions. The researchers then inject the DNA or
RNA into human cells. The cell’s machinery uses the
instructions to make virus antigens that the immune
system reacts to. Cells respond to the instructions as a
normal part of their daily existence. This is the same
trait infectious viruses exploit; they cannot reproduce
on their own, so they use a cell’s machinery to make cop-
ies of themselves. They burst out of the cell and infect
more cells, widening the infection.

Virtually all the labs want to find a way to train
human cells to make an antigen called the spike pro-
tein. It juts out from SARS-CoV-2 like a stud on a tire,
allowing the virus to bind to a human cell and sneak
inside. Almost all the labs are using one of three
approaches to deliver the spike blueprint. The first is
a DNA plasmid, typically a small, hoop-shaped mole-
cule. A plasmid is a handy tool because if a virus
mutates, researchers can readily swap in a new blue-

40  Scientific American, June 2020

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June 2020, ScientificAmerican.com 41

© 2020 Scientific American

CREATE A CHEMICAL SERUM Isolate a How to Develop
The traditional approach inserts virus particle a Virus Vaccine
a modified version of the virus, or
pieces of it, into a solution injected A vaccine exposes the body to an altered,
into the body. But the method is safe version of a disease-causing virus,
slow. Newer genetic engineering prompting the immune system to produce
approaches insert a blueprint of the antibodies—proteins that can stop the real
virus’s genes into the solution. This pathogen from infecting cells. The immune
method is faster but less proved. system then remembers how to fight the
invader. Scientists can use different methods
Adapt it for Map the virus’s to create a chemical vaccine formulation,
a vaccine genetic sequence which they then test for safety and efficacy.

Weaken the virus Kill the virus Use isolated pieces Genetically engineer particular virus genes and capture their blueprint
(attenuated) (inactivated) of the virus

Embed blueprint Embed blueprint Embed blueprint
in DNA plasmid in RNA lipid in an adenovirus

Put particles
into a solution, then test

Testing starts in lab dishes and Test in lab cultures
animals, then proceeds to humans, and animals
advancing from a handful to tens
of thousands. If the vaccine causes
serious side effects or does not
produce antibodies or protect large
numbers of people, it is abandoned.

Yes Does it prompt the immune No Yes
system’s cells to produce No Stop testing
antibodies that will identify
and attach to the virus?

Human testing

Phase 1: No Phase 2: No Phase 3: Yes PRODUCTION
Is the vaccine safe? Yes Is the vaccine safe? Yes Does it safely A successful vaccine must
Are bad side effects prevent infection be approved by regulators,
avoided? Does the Is the immune and disease across then manufactured in volume
response strong? a large number and tested for product quality.
immune system of people?
produce antibodies? Is the dosage People tested:
People tested: 10,000s +
10–100 People tested:

42  Scientific American, June 2020 Graphic by Jen Christiansen

© 2020 Scientific American

print. DNA-plasmid vaccines have been made for veter- lab cultures, it is assessed in animals to see if it is safe IN BRIEF
inary uses in fishes, dogs, swine and horses, but human and whether it elicits an immune response. Next it is To quickly create
applications have lagged, mostly because the vaccines tested in people—first small groups to check on safety
have had difficulty passing through a cell’s protective and side effects, then increasingly larger numbers to see p otential vaccines
outer membrane to reach the machinery inside. One how effective it is. Inovio’s DNA plasmid went into small- against COVID-19,
recent improvement is to inject the vaccine with an scale human trials on April  6—only three months after researchers are using
instrument that administers brief electrical charges to the SARS-CoV-2 genome was published. Moderna began genetic engineering
cells near the injection site, which open pores in the cell small human trials of its RNA vaccine even sooner, on rather than tradition-
membranes so the vaccine can enter. March 16, and in April the U.S. government pledged up al methods, which
to $483 million to speed mass production if the trials go can take years.
Inovio Pharmaceuticals, headquartered in Plymouth well. Barouch’s lab devised a prototype adenovirus vac- Three different
Meeting, Pa., is employing the DNA-plasmid approach. cine in just four weeks. Johnson & Johnson, in collabo- techniques based on
Several years ago it launched clinical trials targeting ration with Bar­­ ouch’s lab, is now testing it in mice, fer- DNA and RNA mol-
spike proteins of a different coronavirus disease called rets and rhesus macaques. On March  30 the U.S. and ecules are speeding
Middle East respiratory syndrome (MERS). According Johnson & Johnson committed more than $1 billion to to human trials, but
to chief executive officer Joseph Kim, the antibody lev- fund large human clinical trials, which are slated to whether they will
els in vaccinated people “are as good or better than those begin in September if the limited testing proves out. work, or can be
we see in blood samples from people who [naturally] scaled up to millions
recovered from MERS.” The company adapted its plat- Although the time from outbreak to small tests has of doses, is unclear.
form—the plasmid and means for testing it—to make a been far quicker than it would have been using the egg
vaccine for SARS-CoV-2. approach, there is no guarantee that the extended trials Charles Schmidt
of genetically engineered vaccines will not take years. is a freelance journalist
DNA-plasmid vaccines work by transferring the Fortunately, SARS-CoV-2 does not appear to mutate as based in Portland,
genetic blueprint to RNA in the cell machinery, which quickly as influenza, suggesting that an effective vaccine, Me., covering health
makes the spike antigens. But scientists can skip the once developed, might offer protection for a long time. and the environment.
plasmid step by embedding a blueprint in a strand of He has written for
RNA—a second approach known as RNA vaccines. The In addition to efficacy, the experts are watching the S cientific American
RNA is carried in lipids that are injected into the body; trials for “disease enhancement”—the possibility that a about therapeutic
lipids are fatty molecules that can pass easily into cells. vaccine might inadvertently worsen symptoms of viruses that can infect
Research shows that RNA vaccines may be better than COVID-19, the disease that SARS-CoV-2 causes. Ferrets harmful bacteria
DNA plasmids at mobilizing the immune system to cre- given an experimental SARS vaccine in 2004 developed and about dangerous
ate antibodies. They also seem to induce more potent damaging inflammation. Kim says humans who were contaminants
immunity—a stronger memory in the immune system— treated with the experimental SARS vaccines did not in drinking water.
and therefore require lower doses. Some RNA vaccines experience disease enhancement. But those formula-
are in early-stage clinical trials for other viral illnesses, tions never made it to large-scale human trials because
including rabies, HIV and Zika. Moderna in Cambridge, the outbreak—which sickened about 8,000 people in
Mass., is using this approach for SARS-CoV-2. nearly 30 countries—burned out in just over a year.

RNA vaccines are less stable than DNA-plasmid vac- Companies are accelerating the development time for
cines; common enzymes in the body can quickly degrade a SARS-CoV-2 vaccine in part by testing vaccines in mul-
them. Heat can ruin them, too. RNA vaccines must gen- tiple animal species at once and in parallel with small
erally be kept frozen or refrigerated, which creates logis- numbers of people. Usually the process is one animal at
tical hurdles, particularly in poorer countries. DNA-plas- a time, and people later, to make sure that side effects are
mid vaccines are stable at higher temperatures. small, that immune response is large and that disease is
actually defeated. Lack of time warrants greater risk.
Barouch and his collaborators at Johnson & Johnson
are using a third approach: inserting the DNA blueprint Protecting the globe against COVID-19 will require
into a common cold virus. When injected, this adenovi- enormous manufacturing capacity. The DNA-plasmid
ral vector, as it is called, infects human cells and delivers and RNA vaccines have never been scaled up to millions
the blueprint it is carrying. Adenoviruses are good at get- of doses, and small firms such as Inovio and Moderna
ting into cells, yet past work shows that the human would not have such capacity in-house. According to
immune system readily recognizes some adenoviruses Barouch, the adenovirus vaccine is more time-consum-
and attacks them before they can sneak in. Barouch is ing at the outset, but once proved it “can be scaled up
using an adenovirus that testing shows is unlikely to be quickly.” Johnson  & Johnson used an adenovirus ap­­
recognized. Some experts also worry an adenovirus itself proach to generate millions of doses of a vaccine against
could replicate inside the body and cause disease. To Ebola, which are now in widespread human trials. A few
address that possibility, Barouch’s team is using an engi- groups are investigating other DNA techniques that
neered virus that is nonreplicating—it cannot make cop- could take longer.
ies of itself ins­­ ide a human cell, because it needs a sub-
stance for replication the human body does not provide. No prototype vaccine is a clear favorite yet, according
In late April the University of Oxford began a limited to Brenda G. Hogue, a virologist and coronavirus expert
human trial with another nonreplicating adenovirus. at Arizona State University. But she says the speed of the
genetics work and the full weight companies are throw-
Once a vaccine’s basic functionality is confirmed in ing behind it are encouraging: “I feel very positive.” 

June 2020, ScientificAmerican.com 43

© 2020 Scientific American



By Lydia Denworth
W e know how t he covid-19 pandemic
began: Bats near Wuhan, China, hold sense of normalcy. Three of those experiences, Cobey
a mix of coronavirus strains, and and other experts say, suggest that what happens next
sometime last fall one of the strains, depends on both the evolution of the pathogen and of
opportunistic enough to cross species the human response to it, both biological and social.

lines, left its host or hosts and ended up in a person. A SPREADING PROBLEM
Viruses are constantly mutating. Those that trigger
Then it was on the loose. pandemics have enough novelty that the human
immune system does not quickly recognize them as dan-
What no one knows yet is how the pandemic will end. gerous invaders. They force the body to create a brand-
new defense, involving new antibodies and other
This coronavirus is unprecedented in the combination immune system components that can react to and
attack the foe. Large numbers of people get sick in the
of its easy transmissibility, a range of symptoms going short term, and social factors such as crowding and the
unavailability of medicine can drive those numbers even
from none at all to deadly, and the extent that it has dis- higher. Ultimately, in most cases, antibodies developed
by the immune system to fight off the invader linger in
rupted the world. A highly susceptible population led to enough of the affected population to confer longer-term
immunity and limit person-to-person viral transmis-
IN BRIEF near exponential growth in cases. “This is a distinct and sion. But that can take several years, and before it hap-
very new situation,” says epidemiologist and evolution- pens, havoc reigns.
The end game ary biologist Sarah Cobey of the University of Chicago.
w ill likely involve
a mix of efforts But past pandemics do offer hints of the future.
that stopped histor- While there is no one historical example to follow,
ic outbreaks: social- humanity has gone through several large epidemics in
control measures, the past 100 or so years that eventually stopped ravag-
medications and ing society. The ways they came to a halt offer guidance

a vaccine. to a world looking for ways to restore health and some

44  Scientific American, June 2020

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LEARNING TO LIVE WITH A DISEASE. The most famous ter. As a result, the virus much more rapidly went the way Lydia Denworth
example of this dynamic in modern history was the H1N1 of the 1918 virus, becoming a widely circulating seasonal is a Brooklyn, N.Y.–
influenza outbreak of 1918–1919. Doctors and public flu, from which many people are now protected either based science writer,
health officials had far fewer weapons than they do today, by flu shots or by antibodies from a previous infection. a contributing editor
and the effectiveness of control measures such as school for Scientific American,
closures depended on how early and decisively they were THE CURRENT END GAME a nd author of Friend­
implemented. Over two years and three waves, the pan- Projections about how COVID-19 will play out are specu- ship: The Evolution,
demic infected 500 million and killed between 50  mil- lative, but the end game will most likely involve a mix of Biology, and Extra­
lion and 100 million. It ended only as natural infections everything that checked past pandemics: Continued ordinary Power of Life’s
conferred immunity on those who recovered. social-control measures to buy time, new antiviral med- Fundamental Bond
ications to ease symptoms, and a vaccine. The exact for- ( W. W. Norton, 2020).
The H1N1 strain became endemic, an infectious dis- mula—how long control measures such as social distanc-
ease that was constantly with us at less severe levels, cir- ing must stay in place, for instance—depends in large part
culating for another 40 years as a seasonal virus. It took on how strictly people obey restrictions and how effec-
another pandemic—H2N2 in 1957—to extinguish most tively governments respond. For example, containment
of the 1918 strain. One flu virus kicked out another one, measures that worked for COVID-19 in places such as
essentially, and scientists don’t really know how. Human Hong Kong and South Korea came far too late in Europe
efforts to do the same have failed. “Nature can do it, we and the U.S. “The question of how the pandemic plays
cannot,” says virologist Florian Krammer of the Icahn out is at least 50 percent social and political,” Cobey says.
School of Medicine at Mount Sinai in New York City.
CONTAINMENT. The severe acute respiratory syndrome The other 50 percent will probably come from science.
(SARS) epidemic of 2003 was caused not by an influ- Researchers have banded together like never before and
enza virus but by a coronavirus, SARS-CoV, that is close- are working on multiple fronts to develop remedies. If
ly related to the cause of the current affliction, SARS- any of the several antiviral medications currently in
CoV-2. Of the seven known human coronaviruses, four development prove effective, they will improve treatment
circulate widely, causing up to a third of common colds. options and lower the numbers who get seriously ill or
The one that caused the SARS outbreak was far more die. A technique to screen for SARS-CoV-2 neutralizing
virulent. Thanks to aggressive epidemiological tactics antibodies, an indicator of immunity in recovered
such as isolating the sick, quarantining their contacts patients, could also prove very useful. Krammer and his
and implementing social controls, bad outbreaks were colleagues have developed one such test, and there are
limited to a few locations such as Hong Kong and Toron- others. Previously used only in local epidemics, these new
to. This containment was possible because sickness fol- serological assays won’t end the pandemic, but they could
lowed infection very quickly and obviously: almost all make it possible to spot and use antibody-rich blood as
people with the virus had serious symptoms such as a treatment for critically ill patients; more certainly, the
fever and trouble breathing. And they transmitted the tests will also get people back to work faster if those who
virus after getting quite sick, not before. “Most patients fought off the virus and are immune can be identified.
with SARS were not that contagious until maybe a week
after symptoms appeared,” says epidemiologist Benja- It will take a vaccine to stop transmission. That will
min Cowling of the University of Hong Kong. “If they take time—probably a year from now. Still, there is rea-
could be identified within that week and put into isola- son to think a vaccine could work effectively. Compared
tion with good infection control, there wouldn’t be with flu viruses, coronaviruses don’t have as many ways
onward spread.” Containment worked so well there to interact with host cells. “If that interaction goes away,
were only 8,098 SARS cases globally and 774 deaths. The [the virus] can’t replicate anymore,” Krammer says.
world has not seen a case since 2004. “That’s the advantage we have here.” It is not clear
VACCINE POWER. When a new H1N1 influenza virus, whether a vaccine will confer long-term immunity as
known as swine flu, caused a pandemic in 2009, “there with measles or short-term immunity as with flu shots.
was an alarm bell because this was a brand-new H1N1,” But “any vaccine at all would be helpful at this point,”
Cowling says, and it was very similar to the 1918 killer. says epidemiologist Aubree Gordon of the University
Swine flu proved less severe than feared. In part, Kram- of Michigan.
mer says, “we were lucky because the pathogenicity of
the virus wasn’t very high.” But another important rea- Unless a vaccine is administered to all of the world’s
son was that six months after the virus appeared, sci- eight billion inhabitants who are not currently sick or
entists developed a vaccine for it. recovered, COVID-19 is likely to become endemic. It will
circulate and make people sick seasonally—sometimes
Unlike measles or smallpox vaccines, which can con- very sick. But if the virus stays in the human population
fer long-term immunity, flu vaccines offer only a few years long enough, it will start to infect children when they
of protection. Influenza viruses are slippery, mutating rap- are young. Those cases are typically, though not always,
idly to escape immunity. As a result, the vaccines must be quite mild, and so far the children appear less likely to
updated every year and given regularly. But during a pan- develop severe disease if they get reinfected as adults.
demic, even a short-term vaccine is a boon. The 2009 vac- The combination of vaccination and natural immunity
cine helped to temper a second wave of cases in the win- will protect many of us. The coronavirus, like most
viruses, will live on—but not as a planetary plague. 

June 2020, ScientificAmerican.com 45

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A remarkable fossil reveals that the digits
in our hands evolved before vertebrates
left the water to colonize land

By John A. Long and Richard Cloutier

Illustration by Chase Stone

46  Scientific American, June 2020

© 2020 Scientific American

old fish closely
related to four-
limbed animals,
had digit bones
in its pectoral fins
that could have
helped support
the animal’s
weight on land.

June 2020, ScientificAmerican.com 47

© 2020 Scientific American

John A. Long i s strategic professor in paleontology at Flinders University in South
Australia. His research focuses on the early evolution of vertebrates, including the
three-dimensionally preserved Devonian-age fossil fishes found in the Gogo
formation in Western Australia. In 2020 he received the prestigious Bettison and
James Award for lifelong achievement for his work as both a scientist and an author.

Richard Cloutier i s a professor-researcher in evolutionary biology at the
University of Québec at Rimouski. His research interests revolve around
the evolutionary patterns and mechanisms of early vertebrates, as well as
the evolutionary developmental biology of recent fishes and amphibians.
He has been working on the fauna, paleoecology and paleoenvironment
of the Devonian Miguasha fossil site for more than 30 years.

ive digits radiating from a palm, an arrangement both ­flexible and strong—
capable of playing a piano, wielding a hammer, offering a comforting touch.
The hand is our most familiar body part, central to most everyday tasks, from
dressing and driving to cooking and texting. Yet from an evolutionary stand-

Fpoint, it remains largely mysterious, particularly when it comes to the earliest
stage of its origin. Other four-limbed creatures—tetrapods, as they are known—
have hands that look and function quite differently than ours do. In birds and
bats, they help to form delicate wings; in elephants, they support limbs as big around as tree
trunks. But the basic structure is the same. In 1859 Charles Darwin remarked on the similarities
in On the Origin of Species: “ What can be more curious than that the hand of a man, formed
for grasping, that of a mole for digging, the leg of the horse, the paddle of the porpoise, and
the wing of the bat, should all be constructed on the same pattern, and should include the same
bones, in the same relative positions?”

IN BRIEF Darwin proposed an elegant explanation: these our fingers, showing that digits evolved before verte-
diverse animals share this pattern because they evolved brates left the water. This discovery overturns the con-
How the hands from a common ancestor that possessed limbs with dig- ventional wisdom about when and how the hand
of four-limbed its. In the more than 160 years since Darwin advanced evolved and shines new light on the rise of tetrapods,
creatures evolved his revolutionary idea, evolutionary biologists have a pivotal event in the history of life on earth.
from the fins of marshaled evidence from paleontology, genetics and
their fish ancestors embryology that has proved him right. Their efforts MURKY ORIGINS
has long been have illuminated the shared ancestry of tetrapods, Until recently, scientists’ grasp of the evolutionary
hard to pin down which evolved from fish; shown that the bones that transition between fishes and early tetrapods hinged
because of a dearth make up the human hand are also found in frogs and mainly on several spectacular fossils that seem to
of fos­s­ ils document- birds and whales; and identified some of the genes that bridge these two groups. One is from a fish called Pan-
ing the transition. control the development of hands and wings and flip- derichthys rhombolepis f rom the Baltic region and
The recent discov- pers, among other variations. But the first chapter of dates to the Middle to Late Devonian period (around
ery of a complete that story—the bit where the hand and wrist evolved 384 million to 379 million years ago). With its elongat-
skeleton of a from bones in the fin of an ancestral fish—has remained ed humerus and large radius and ulna (the upper arm
375-million-year-old murky at best because scientists have lacked sufficient- bone and forearm bones, respectively, in tetrapods) and
fish is upending ly complete fossils of transitional creatures between its tetrapodlike skull bone pattern, P anderichthys
what researchers fully aquatic fish and land-roving tetrapods. o ffered the first clues that the group of fishes to which
had surmised about it belongs were the closest fishes to the tetrapods. The
the origin of hands This past March we unveiled an extraordinary fos- group is called the elpistostegalians, after the then
and thus the rise sil—a complete skeleton of a 375-million-year-old fish, poorly known E lpistostege from eastern Canada.
of tetrapods. Elpistostege watsoni —that goes a long way toward fill-
ing that gap in understanding. The fossil preserves in In 2006 Neil Shubin of the University of Chicago
its fins bones comparable to the ones that make up and his colleagues announced the discovery of anoth-

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