New Scientist - UK (2022-06-11)

11 June 2022 | New Scientist | 7

RATHER than jumping to

humans from animals recently,

the monkeypox virus variant

currently cropping up around the

world may have been undetected

in people for years, DNA

sequencing appears to show.

“We therefore suggest that

the pattern we see... means that

there has been sustained human

to human transmission since at

least 2017,” states an initial report

by Áine O’Toole and Andrew

Rambaut at the University

of Edinburgh in the UK.

Because monkeypox normally

circulates in animals in some

African countries and occasionally

jumps to people there, person-to-

person spread is more likely to

have gone unnoticed for years

on that continent, says Emma

Hodcroft at the University

of Bern in Switzerland.

But sometime this year, the

virus spread to Europe and

beyond. As of 7 June, monkeypox

infections have been confirmed

in more than 1000 people in

27 countries, including more than

200 in England. Most cases are

in men who have sex with men.

Genome sequencing shows

that the monkeypox viruses

responsible for these cases are

closely related to ones detected in

a small number of cases in Israel,

Nigeria, Singapore and the UK

between 2017 and 2019.

There are up to 47 DNA-letter

changes in the latest viruses

compared with the earlier cases.

This is unexpectedly high given

that the monkeypox virus is

thought to evolve slowly, by

around one mutation per year.

What is striking is that 42 of

these 47 changes involve the DNA

letters TT changing to TA, or GA

to AA. There is a group of human

enzymes called APOBEC3 that

help defend against viruses

by inducing mutations in their

DNA, and these are the kinds

of changes they produce.

“If these APOBEC3 edits

are specifically indicative of

replication in humans as opposed

to another host species then

this would confirm this entire

clade to be representative of the

emergence of a human epidemic

by 2017,” O’Toole and Rambaut

The virus variant responsible for a worldwide outbreak may have

been circulating in people for years, reports Michael Le Page

Monkeypox unnoticed?

KA
TE
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Diseases

stated in a 5 June update to

their report.

On 3 June, the US Centers for

Disease Control and Prevention

reported that three of the 10

monkeypox viruses sequenced in

the US differed slightly from the

others, while still being related to

the 2017 viruses. These three were

found in people who had travelled

to different countries in Africa and

the Middle East in 2021 or 2022.

The three cases could be due

to independent instances of the

virus jumping from some animal

reservoir into people. However,

because they also have lots of

APOBEC3-like mutations, another

explanation is that monkeypox

has been spreading quite widely

in people in Africa since 2017.

Surprisingly, rather than having

evolved to be fitter and better at

spreading in people, the existing

viruses may be less fit than the

2017 ones, because they are

accumulating lots of mutations

that are probably detrimental.

While this is reassuring, we

don’t know they won’t evolve to

be better at spreading in people

if we give them a chance to do so,

says Hodcroft. “It’s much better

for us to do what we can to ensure

we don’t find out the answer to

that,” she says. “The less a virus

circulates in a host, the less chance

it has for that kind of adaption.”

While the monkeypox cases so

far may have been mild, this might

not be true if the monkeypox virus

starts infecting children or people

who are immunocompromised,

says Hodcroft.

“I don’t think there is any

reason to panic and I do think this

is something we can absolutely

get under control,” she says. “But

this is something we should take

seriously. We don’t want to swing

too far the other way because

we are really sick of viruses.” ❚

An illustration

of monkeypox

virus particles

Phone home

Quantum trick

to help converse

with aliens p

Insect explorers

How termites sailed

around the world’s

oceans p

Squinting shells

Baby leatherback

turtles have poor

eyesight p

Shark showdown

Did great whites

outcompete

megalodon? p

Downside of height

Tall people have

a greater risk of

certain diseases p

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