24 | New Scientist | 2 April 2022Infectious diseasesWE often think of diseases passing
from other animals to people, as in
the case of covid-19, but they go the
other way too and we seem to have
vastly underestimated this spread.
Anna Fagre at Colorado State
University and her team searched
previously published research for
all papers that describe human-to-
animal disease transmission that
didn’t involve the new coronavirus.
The group found 97 reports,
involving bacteria, viruses, fungi
and parasites. Of these, 57 involved
transmission to primates – probably
because it is easier for pathogens
to jump between humans and more
closely related species (Ecology
Letters, doi.org/hm3h).
Many of the transmission events
involved zoo animals – for instance,
a cheetah that caught a human flu
strain – but they also involved wildanimals, such as mountain gorillas
in Uganda (pictured) catching
several bacterial infections. “I think
there’s a lot more transmission
happening than we are currently
picking up,” says Fagre.
There were no confirmed cases
of a disease crossing to an animal
species and continuing to spread
between individuals. But several
wild skunk have been found to be
infected with human influenza,
which suggests that there may
be ongoing transmission. And the
virus that causes covid-19 is now
spreading widely among white-
tailed deer in North America.
There is a chance these diseases
could harm the animals, but there
is also the risk a pathogen mutates
while in another host and becomes
more dangerous for people, if it
crosses back. Clare WilsonHuman-to-animal infections
more common than thought
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News In brief
PANCREATIC tumours have been
drastically shrunk in mice using
a strategy that allows the immune
system to kill the cancer cells. The
method may one day help to treat
this deadly disease in people.
Most people with pancreatic
cancer don’t survive long because
the cancer often spreads before
symptoms arise and we lack
effective treatments.
Many cancers can be treated
using therapies that boost the
cancer-fighting abilities of the
immune system. However, these
don’t usually work for pancreatic
cancer as it isn’t easily detected by
the immune system. The tumours
also tend to be surrounded by cells
that suppress immune activity.
To address this, Claudia
Gravekamp at Albert Einstein
College of Medicine in New York
and her team used listeria bacteria,
which are attracted to tumours, toMedicine^deliver an inactivated form of
tetanus toxin to pancreatic cancer.
Because most of us are vaccinated
against tetanus, our immune
systems detect it. So pancreatic
cancer cells loaded with tetanus
should be vulnerable to attack.
To test this, the researchers gave
tetanus vaccines to young mice
engineered to develop pancreatic
cancer. When the animals had
advanced cancer, the listeria
bacteria were injected into them.
This successfully delivered
tetanus to the tumours, making
them visible to the immune
system, which attacked the cancer.
This was amplified by giving the
mice a drug that stopped some of
the cells around the tumours from
suppressing immune activity.
This reduced the size of the
pancreatic tumours and those that
had spread to other parts of the
body by over 80 per cent. It also
improved the average survival
time of the mice by 40 per cent
(Science Translational Medicine,
doi.org/hm6n). Alice KleinTetanus trick tackles
hard-to-treat cancerAN ELASTIC polymer that can
glow like a filament in a light bulb
could lead to flexible screens that
are affordable, practical and robust.
These could form part of
wearable computers that stick
to our skin and do away with
the need to carry a smartphone
or laptop. But existing flexible
displays have flaws: they either
require high voltages; are lacking
brightness; aren’t bendy enough;Technologyor are too fragile or too expensive.
Zhenan Bao at Stanford
University in California and her
team have created a light-emitting
plastic material that can be
stretched up to twice its original
length without tearing. The
polymer is up to twice as bright
as smartphone screens. When an
electrical charge is passed through
the material, it causes photons to
be emitted, creating red, green or
blue light. A thin film can be stuck
onto skin and doesn’t rip when it
flexes (Nature, doi.org/hm6j).
So far, the researchers have
demonstrated small, static
examples of the films in single
colours. To be useful for devices,
they will need to develop a larger
version with discrete pixels and
control technology to allow the
image on the screen to change.
Harish Bhaskaran at the
University of Oxford says a light-
emitting polymer that is robust
and cheap to manufacture could
make new types of smart device
ZH practical. Matthew SparkesANG^ AND
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H^ LABA screen that you
wear like a plaster