-
Sputnik virophage
Mimivirus neu
tral
ised
coro
navi
rus
aden
ovirus
vect
orRN
Ava
ccin
e
100 nm = 1/10,000th of a mm
CORONAVIRUS VACCINES
coronavirus
S
E M
N
MM M
SS S
hepatitis C virus
RNA
capsid
lipid
E
apolipoprotein
E
EHeartland virus
GnGcGnGc
GnGc
NL
influenza virus
HANA
M2M1
HAHA HAHAHA
NP
anellovirus
ssDNA
capsid
Lassa virus
GP
matrix
N
GP
GP
N
N
ribosome
Zika virus
capsid
RNA
EE
hepatitis B virus
ssDNA
dsDNA
core
L MS
ssRNA
SS
SS
immature HIV mature HIV
gp12-gp41
gp12-gp41 gp12-gp41
gp12-gp41 matrix
matrix
capsid
capsid
genome
enzymes
host proteinshost proteinscalicivirus
capsid
RNA
Bluetongue virus
capsid
RNA
capsidcapsid
Pol
rotavirus
capsid
RNA
capsidcapsid
Pol
adenovirus
capsidfibre
DNA
herpes simplex virus
membrane
envelope proteins
tegument
capsid
DNA
capsid
DNA
membrane
membrane
capsid
fibres
core
mRNA
antibodyS
DNAencoding
coronavirusgene
Freely available under a Creative Commons LicenseCC BY 4.0 (2020) Ed Hutchinson, MRC-University of Glasgow Centre for Virus Research
S
-
Viruses and snowflakes
A traditional Christmas activity, here in Glasgow and in many other parts of the world, is making paper snowflakes. Fold up a circle of paper, cut a design into it, unfold it again and you end up with a symmetrical design that looks like a snowflake. If, like my colleagues at the MRC-University of Glasgow Centre for Virus Research, you spend a lot of time thinking about the microscopic world, these symmetrical decorations can also remind you of something else – viruses.
Virus particles and symmetry
Why would viruses look like snowflakes? After all, we don’t expect bacteria to look like snowmen or fungi to look like icicles (although some do; nature is quite varied).
It becomes clear if we think about what a virus is. A virus is a set of genetic instructions that take over a cell and turn it into a factory for making more viruses. Importantly, one of the things the viral genes make the cell do is to produce microscopic particles that can package up new copies of viral genes, in order to transport them to new host cells. These infectious virus particles (or ‘virions’) are very distinctive, and are usually the first thing we think of when we think ‘virus.’ They are, if you can leave the associations with disease aside, quite beautiful.
One of the things that makes virus particles beautiful is that they are often symmetrical. Indeed, some virus particles are so regular that,
like the water that forms snowflakes, they will assemble into crystals if they are kept under the right conditions in a laboratory – this trick has
Snowflake (Alexey Kljatov, 2015)
An icosahedron (Tilman Piesk, 2015), and an icosahedral calcivirus particle, shown in 3D
and in cross-section (Conley et al. (2019) Nature 565 (7739) 377-381).
-
been used by crystallographers to study their invisible small structures in great detail.
Why are virus particles so regular?
Virus particles are symmetrical because, despite the huge impact they have on our world, viruses are very simple. Compared to us, viruses have very few genes, and so they need to make virus particles from an extremely small set of components, which they use repeatedly.
One way to do this is to assemble a regular box of ‘capsid’ proteins to enclose the viral genes (an icosahedron, which has twenty sides). A 2D projection of an icosahedron is roughly hexagonal, giving it the same symmetry as a snowflake.
Another way to make virus particles is for the virus to steal components from our own cells. Many virus particles are wrapped in a layer of membrane obtained from the cell they grew in – a good way of protecting the viral genes, though it can be disrupted by detergents in soap, or alcohol in hand gels. Surface tension tends to pull membranes into spheres, and proteins that float in them or within them tend to spread out to a roughly even spacing.
Because of this, it turns out that many viruses can be made into paper snowflakes. (A little bit of tweaking was needed to make them fit the symmetry of Christmas decorations exactly, and if you are already interested in viruses you can try and predict where that was needed.)
Virus Snowflakes
In this collection you’ll find viruses that we care about because they make people sick, and viruses that we care about because they make animals sick. You will find viruses that don’t do either of these things but are just really cool – the enormous Mimivirus and the tiny satellite virus that infects it (a virus infecting a virus!); the unobtrusive anellovirus, which you are likely to be infected with right now without noticing it or having any ill-effects.
You will not find some viruses, either because they are not symmetrical enough (the tailed bacteriophage, or bacteria-infecting viruses, that resemble lunar landing modules are among the most beautiful viruses but they only have one copy of their long tail) or because they have the wrong sort of symmetry (this includes viruses that stack their capsid proteins into a helix, like the filament-shaped Ebola virus, and certain viruses that have distinctive shapes like the bullet-shaped rabies virus, the brick-shaped smallpox virus or the lemon-shaped viruses that infect some single-celled archaea).
Finally, this collection was put together in a year dominated by one particular virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) the cause of coronavirus disease 2019 (COVID-19) and the resulting pandemic. Happily, by understanding the structure of virus particles we now have some tools to fight it, and this collection ends with two SARS-CoV-2 vaccines inspired by virus structures, as well as a final snowflake showing how vaccination can protect us against SARS-CoV-2 – perhaps the best Christmas gift any of us could have this year.
Other Resources
* More free resources for learning about viruses, including a colouring book, 3D paper art models (including of helical viruses) and an augmented reality app, can be found with the files for these snowflakes at the website of the MRC-University of Glasgow Centre for Virus Research (https://tinyurl.com/yc8edw7a). * These virus snowflakes were based on a wide variety of research papers but I was also grateful, as many virologists are, for the excellent virus summaries at ViralZone (https://viralzone.expasy.org). Any errors are mine, though some of them, due to the unforgiving symmetry relationships of Christmas decorations, were deliberate.
Artistic representation of SARS-CoV-2, which is wrapped in an envelope of membrane
(David S. Goodsell, RCSB Protein Data Bank; doi: 10.2210/rcsb_pdb/goodsell-gallery-024).
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
een
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Ade
novi
ruse
s ca
use
a va
riet
y of
illn
esse
s, p
artic
ular
ly
cold
-lik
e sy
mpt
oms
and
conj
unct
iviti
s. T
hey
can
be g
enet
ical
ly m
odifi
ed t
o de
liver
gen
es.
Thes
e fin
ds u
ses
in g
ene
ther
apy
and
in v
acci
nes
for
viru
ses
incl
udin
g SA
RS-
CoV
-2.
An
aden
ovirus
par
ticle
's 1
2 co
rner
s ar
e de
cora
ted
with
long
, sp
ike-
like
fibre
s, w
hich
it u
ses
to
atta
ch t
o ne
w c
ells
. In
side
the
pa
rtic
le a
re c
ore
and
min
or/c
emen
t pr
otei
ns,
whi
ch h
elp
to p
acka
ge
the
viru
s' D
NA g
enom
e.
-
Dif
ficu
lty:
Eas
y
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Mem
bers
ofth
is v
irus
fam
ily a
re
not
know
n to
cau
se d
isea
se,
but
they
are
ext
rem
ely
com
mon
- it
is
like
ly t
hat
anel
lovi
ruse
s ar
e re
plic
atin
g in
side
you
r bo
dy a
t th
e m
omen
t w
ithou
t yo
u ev
en n
otic
ing.
Ane
llovi
ruse
s fo
rm s
impl
e pa
rtic
les:
an
icos
ahed
ral b
ox o
f ca
psid
pro
tein
s su
rrou
nd a
cir
cle
of s
ingl
e-st
rand
ed
DN
A,
whi
ch g
ives
the
vir
us it
s na
me
(fro
m a
nello
, 'rin
g').
The
vir
us r
elie
s on
our
ow
n en
zym
es t
o m
ake
mor
e co
pies
of its
gen
ome.
-
Dif
ficu
lty:
Eas
y
Ab
out
the
Vir
us
Par
ticl
e:Cal
iciv
irus
es a
re t
rans
mitt
ed b
ya
20 s
ided
(ic
osah
edra
l) p
artic
le,
whi
ch c
onta
ins
the
vira
l gen
ome.
Onc
e it
is in
side
a c
ell,
the
part
icle
rear
rang
es it
self.
A p
ore
open
s in
its s
urfa
ce,
allo
win
g th
e vi
ral
geno
me
to e
scap
e an
d ta
ke c
ontr
olof
the
cel
l's fun
ctio
ns.
Ab
out
the
Vir
us:
Cal
iciv
irus
es a
re a
fam
ily o
f vi
ruse
sth
at c
ause
dis
ease
s in
clud
ing
one
of t
he m
ost
com
mon
infe
ctio
usfo
rms
of v
omiti
ng a
nd d
iarr
hoea
,w
inte
r vo
miti
ng d
isea
se.
Oth
erca
liciv
irus
es in
fect
pet
s, n
otab
lyfe
line
calic
ivir
us,
whi
ch c
ause
sa
resp
irat
ory
infe
ctio
n in
cat
s.
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed H
utch
inso
n, M
RC-U
nive
rsity
of
Gla
sgow
Cen
tre
for
Vir
us R
esea
rch
Diff
eren
t co
rona
viru
ses
can
infe
ct
man
y sp
ecie
s of
mam
mal
s an
d bi
rds.
In
hum
ans,
cor
onav
irus
es a
re o
ne
of t
he c
ause
s of
the
com
mon
col
d.
Som
e co
rona
viru
ses
are
mor
e se
riou
s: S
ever
e Acu
te R
espi
rato
ry
Synd
rom
e Cor
onav
irus
2 (
SARS-
CoV
-2),
w
hich
cau
ses
Cor
onav
irus
dis
ease
201
9 (C
OVID
-19)
has
cau
sed
a w
orld
- ch
angi
ng p
ande
mic
.
The
long
spi
kes
of S
pro
tein
, w
hich
re
sem
ble
aso
lar
coro
na(o
r'c
row
n')
give
the
vir
us it
s na
me.
S b
inds
to
new
ho
st c
ells
, w
hich
can
be
bloc
ked
by
antib
odie
s. T
he v
irus
has
a m
embr
ane
whi
ch c
an b
e de
stro
yed
by s
oap
or
alco
hol,
and
insi
de t
his
the
RN
A g
enom
e is
wra
pped
in m
any
copi
es o
f N
pro
tein
.
-
Dif
ficu
lty:
Eas
y
Ab
out
the
Vir
us
Par
ticl
e:Th
e ge
nom
e of
Hea
rtla
nd v
irus
cons
ists
of th
ree
segm
ents
of RN
A,
each
wra
pped
in n
ucle
opro
tein
s an
dbo
und
to a
pol
ymer
ase
prot
ein.
The
viru
s pa
rtic
le's
mem
bran
e is
coa
ted
in a
latt
ice
of v
iral
pro
tein
s.
Ab
out
the
Vir
us:
Hea
rtla
nd v
irus
, di
scov
ered
in 2
009
and
nam
ed a
fter
Hea
rtla
nd R
egio
nal
Med
ical
Cen
ter
in M
isso
uri,
is a
nex
ampl
e of
a b
unya
viru
s.Bun
yavi
ruse
s ar
e a
dive
rse
orde
r of
anim
al a
nd p
lant
vir
uses
, m
ost
ofth
em t
rans
mitt
ed b
y bi
ting
arth
ropo
ds -
in t
he c
ase
ofH
eart
land
vir
us,
by t
icks
.
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
fG
lasg
ow C
entr
e fo
r Vir
us R
esea
rch
Ther
e ar
e m
any
vira
l dis
ease
s th
at
can
caus
e in
flam
mat
ion
of t
he li
ver
(hep
atiti
s),
whi
ch c
an le
ad t
o liv
er
failu
re a
nd c
ance
r. H
epat
itis
B v
irus
(H
BV)
is a
glo
bal h
ealth
pro
blem
, th
ough
infe
ctio
n ca
n be
pre
vent
ed
by v
acci
natio
n.
HBV h
as a
n un
usua
l gen
ome,
fo
rmed
par
tly fro
m d
oubl
e-st
rand
ed
DN
A,
part
ly fro
m s
ingl
e-st
rand
ed
DN
A,
and
part
ly fro
m s
ingl
e-st
rand
ed
RN
A.
This
is w
rapp
ed in
a s
mal
l par
ticle
of
mem
bran
e an
d vi
ral p
rote
ins.
-
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Ther
e ar
e m
any
vira
l dis
ease
s th
at
can
caus
e in
flam
mat
ion
of t
he li
ver
(hep
atiti
s).
Hep
atiti
s C v
irus
(H
CV)
is
a m
ajor
cau
se o
f vi
ral h
epat
itis,
whi
ch
caus
es c
hron
ic il
lnes
s, li
ver
failu
re
and
canc
er.
Rece
ntly
, im
prov
ed d
rugs
ha
ve m
ade
HCV m
uch
easi
er t
o tr
eat
and
cure
.
The
sing
le-s
tran
ded
RN
A o
f th
e H
CV
geno
me
is s
urro
unde
d by
a la
yer
of
mat
rix
prot
ein
and
wra
pped
in
mem
bran
e. H
CV p
artic
les
can
fuse
w
ith t
he li
popr
otei
n pa
rtic
les
that
tr
ansp
ort
lipid
s ar
ound
the
bod
y.
-
Dif
ficu
lty:
Har
d
Ab
out
the
Vir
us
Par
ticl
e:A h
erpe
s vi
rus
part
icle
is c
ompl
ex.
It is
sur
roun
ded
by a
mem
bran
e th
atis
stu
dded
with
viral
pro
tein
s. I
nsid
eth
is is
a t
hick
pro
tein
coa
t, c
alle
d th
ete
gum
ent.
With
in t
his
is a
20-
side
d(i
cosa
hedr
al)
shel
l or
caps
id,
whi
chco
ntai
ns t
he v
iral
gen
ome
- a
long
stra
nd o
f D
NA,
wra
pped
into
a t
ight
ball
to fit
into
thi
s tin
y sp
ace.
Ab
out
the
Vir
us:
Her
pes
viru
ses
are
a fa
mily
of ve
ryco
mm
on v
irus
es t
hat
caus
e lif
elon
gin
fect
ions
. Th
ey c
an li
e hi
dden
for
long
per
iods
but
occ
asio
nally
re-e
mer
ge t
o ca
use
dise
ase.
Her
pes
sim
plex
vir
us 1
, w
hich
hid
es in
ner
vece
lls,
emer
ges
to c
ause
col
d so
res.
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:Tw
o co
pies
of th
e vi
ral g
enom
e ar
esu
rrou
nded
by
a m
embr
ane
and
vira
lpr
otei
ns.
Aft
er t
he v
irus
par
ticle
has
form
ed,
vira
l enz
ymes
cut
the
pro
tein
s,al
low
ing
the
part
icle
to
rear
rang
e in
toits
mat
ure
form
.
Ab
out
the
Vir
us:
HIV
is a
ret
rovi
rus.
Our
cel
ls c
opy
RN
Am
essa
ges
from
a D
NA g
enom
e, b
utH
IV m
akes
a D
NA c
opy
of it
s RN
Age
nom
e (h
ence
'ret
ro')
whi
ch it
perm
anen
tly in
sert
s in
to t
he g
enom
eof
the
whi
te b
lood
cel
ls it
infe
cts.
If
untr
eate
d, t
his
seve
rly
wea
kens
the
imm
une
syst
em,
caus
ing
Acq
uire
dIm
mun
odef
icie
ncy
Synd
rom
e (A
IDS).
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.(5
) To
mat
ure
the
viru
s pa
rtic
le:
re
fold
alo
ng t
he d
ashe
d lin
es.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:Th
e in
fluen
za v
irus
par
ticle
isw
rapp
ed in
a m
embr
ane,
whi
ch is
coat
ed w
ith t
he t
wo
spik
e pr
otei
nsan
d pe
netr
ated
by
a po
re.
Insi
de is
a la
yer
of m
atrix
prot
ein
and
the
eigh
t se
gmen
ts o
f th
e vi
ral g
enom
e.
Ab
out
the
Vir
us:
Influ
enza
virus
es c
ause
influ
enza
,a
com
mon
win
ter
resp
irat
ory
illne
ssth
at c
ause
s fe
ver
and
exha
ustio
n.Spi
kes
on t
heir
sur
face
, H
A a
nd N
A,
can
be b
lock
ed b
y an
tibod
ies
if th
eyar
e of
the
rig
ht s
ort
(H1N
1, H
3N2,
etc)
. H
owev
er,
the
spik
es c
hang
era
pidl
y, a
nd t
he v
acci
nes
whi
chpr
ovid
e im
mun
ity t
o th
em h
ave
tobe
upd
ated
oft
en.
Occ
asio
nally
,hu
man
influ
enza
vir
uses
pic
k up
com
plet
ely
new
spi
kes
from
an
anim
alin
fluen
za v
irus
, al
low
ing
them
to
esca
pe a
ll im
mun
e pr
otec
tion
- th
iscr
eate
s an
influ
enza
pan
dem
ic.
Inst
ruct
ion
s:(1
)Cut
out
the
squa
re.
(2)
Fold
dott
edlin
esto
form
atr
iang
le,
with
the
desi
gnon
top.
(3)
Cut
out
the
desi
gn,
cutt
ing
thro
ugh
the
entir
est
ack.
(4)
Unf
old.
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
eCC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-U
nive
rsity
of
Gla
sgow
Cen
tre
for
Vir
us R
esea
rch
Lass
a ha
emor
rhag
ic fev
er is
a s
ever
e ill
ness
tha
t ca
n be
cau
ght
from
ro
dent
s in
par
ts o
f W
est
Afr
ica.
It
is
caus
ed b
y an
em
ergi
ng v
irus
(on
e th
at is
bec
omin
g m
ore
com
mon
),
calle
d La
ssa
mam
mar
enav
irus
.
The
Lass
a vi
rus
geno
me
cons
ists
of
two
segm
ents
of si
ngle
-str
ande
d RN
A,
boun
d to
viral
pro
tein
s an
d su
rrou
nded
by
mat
rix
prot
ein
and
a m
embr
ane.
Rec
epto
r-bi
ndin
g pr
otei
ns in
the
mem
bran
e al
low
th
e vi
rus
to e
nter
new
cel
ls.
-
Dif
ficu
lty:
Har
d
Ab
out
the
Vir
us
Par
ticl
es:
The
Mim
ivir
us p
artic
le is
icos
ahed
ral
and
deco
rate
d w
ith lo
ng fib
res.
Ins
ide,
mem
bran
es a
nd p
rote
ins
wra
p ar
ound
a co
re c
onta
inin
g th
e D
NA g
enom
e.
The
Spu
tnik
vir
opha
ge p
artic
le is
sm
all,
icos
ahed
ral a
nd c
onta
ins
a ci
rcul
arD
NA g
enom
e.
Ab
out
the
Vir
use
s:Virus
es w
ere
orig
inal
ly id
entif
ied
asm
icro
bes
that
wer
e sm
alle
r th
anba
cter
ia,
but
rece
ntly
gia
nt v
irus
esha
ve b
een
disc
over
ed,
such
as
this
Mim
ivirus
whi
ch in
fect
s am
oeba
e.N
ot o
nly
are
they
big
ger
than
som
eba
cter
ia,
gian
t vi
ruse
s ar
e ev
enex
ploi
ted
by s
mal
ler
'sat
ellit
e' v
irus
es,
or 'v
irop
hage
s,' t
hat
requ
ire
the
gian
tvi
rus
for
thei
r ow
n re
plic
atio
n.
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
eCC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-U
nive
rsity
of
Gla
sgow
Cen
tre
for
Vir
us R
esea
rch
-
Dif
ficu
lty:
Har
d
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Rota
viru
ses
are
an e
xtre
mel
yco
mm
on c
ause
of di
arrh
oea,
part
icul
arly
in y
oung
chi
ldre
n.M
ost
peop
le a
re in
fect
ed a
t le
ast
once
by
the
age
of fiv
e.
The
rota
viru
s pa
rtic
le h
as a
whe
el-l
ike
appe
aran
ce (
rota
mea
ns ‘w
heel
’) a
nd
is for
med
fro
m t
hree
laye
rs o
f ca
psid
pr
otei
ns.
The
inne
r tw
o la
yers
for
m a
co
re t
hat
cont
ains
the
gen
ome,
as
11
segm
ents
of
doub
le-s
tran
ded
RN
A,
and
the
enzy
mes
tha
t co
py it
. Pr
omin
ent
spik
es h
elp
the
part
icle
to
ente
r ce
lls.
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Zik
a vi
rus
is s
prea
d m
ainl
y by
mos
quito
bite
s. I
t w
as fir
st id
entif
ied
in U
gand
a, b
ut it
s ra
nge
is in
crea
sing
.In
201
5 it
reac
hed
the
Am
eric
as a
ndca
used
a m
ajor
epi
dem
ic.
Zik
a fe
ver
is t
ypic
ally
a m
ild il
lnes
s, b
ut in
fect
ions
during
pre
gnan
cy c
an c
ause
mic
roce
phal
y (a
sho
rten
ed h
ead)
in b
abie
s.
The
Zik
a vi
rus
geno
me
is s
ingl
e-
stra
nded
RN
A,
surr
ound
ed b
y m
atrix
prot
ein
and
a m
embr
ane,
whi
ch is
en
clos
ed in
mor
e pr
otei
ns.
The
oute
r pr
otei
ns a
re in
itial
ly r
aise
d up
in
spik
es b
ut fla
tten
aga
inst
the
m
embr
ane
as t
he p
artic
le m
atur
es.
-
Dif
ficu
lty:
Eas
y
Ab
out
the
Par
ticl
e:
Ab
out
the
Vac
cin
e:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
eCom
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Vir
us R
esea
rch
This
is n
ot a
virus
, bu
t in
man
y w
ays
it be
have
s lik
e on
e. I
t is
an
artif
icia
l pa
rtic
le,
desi
gned
to
deliv
er the
in
stru
ctio
ns for
mak
ing
all o
r pa
rt
of t
he S
ARS-C
oV-2
S p
rote
in t
o a
cell.
W
hen
the
cell
mak
es t
his
harm
less
pr
otei
n, t
he im
mun
e sy
stem
lear
ns
to r
ecog
nise
it a
nd c
an t
hen
atta
ck
real
SARS-C
oV-2
par
ticle
s ef
fect
ivel
y.
Like
man
y vi
ruse
s, t
his
vacc
ine
is
a se
t of
RN
A in
stru
ctio
ns for
mak
ing
prot
ein
(mRN
A,
mes
seng
er R
NA)
wra
pped
in a
mem
bran
e. T
he
mem
bran
e is
sta
bilis
ed w
ith s
tran
ds
of p
olye
thyl
ene
glyc
ol (
PEG
) bu
t th
e RN
A it
self
is u
nsta
ble
and
so t
heva
ccin
e ne
eds
to b
e ke
pt v
ery
cold
.
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Ab
out
the
Vir
us:
Inst
ruct
ion
s:
(1)
Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
Blu
eton
gue
dise
ase
affe
cts
rum
inan
ts,
incl
udin
g ca
ttle
, go
ats
and
part
icul
arly
sh
eep.
It
can
caus
e se
riou
s di
seas
e,
incl
udin
g th
e sw
olle
n, b
luei
sh t
ongu
e th
at g
ives
it it
s na
me.
The
vir
us t
hat
ca
uses
blu
eton
gue
dise
ase
is s
prea
d by
mid
ge b
ites.
The
blue
tong
ue v
irus
par
ticle
is for
med
fr
om t
hree
laye
rs o
f ca
psid
pro
tein
s.
The
inne
r tw
o la
yers
form
a c
ore
that
co
ntai
ns 1
0 se
gmen
ts o
f do
uble
- st
rand
ed R
NA g
enom
e, a
nd t
he
enzy
mes
tha
t co
py it
.
-
Dif
ficu
lty:
Med
ium
Ab
out
the
Vir
us
Par
ticl
e:
Inst
ruct
ion
s:(1
) Cut
out
the
squ
are.
(2)
Fold
dot
ted
lines
to
form
a
tria
ngle
, w
ith t
he d
esig
n on
top
.(3
) Cut
out
the
des
ign,
cut
ting
th
roug
h th
e en
tire
stac
k.(4
) U
nfol
d.
Free
ly a
vaila
ble
unde
r a
Cre
ativ
e Com
mon
s Li
cens
e CC B
Y 4.
0 (2
020)
Ed
Hut
chin
son,
MRC-
Uni
vers
ity o
f G
lasg
ow C
entr
e fo
r Virus
Res
earc
h
This
is w
hat
the
end
of a
pan
dem
ic
look
s lik
e.
Cor
onav
irus
par
ticle
s en
ter
cells
by
bind
ing
to t
hem
with
the
sp
ikes
of S p
rote
in o
n th
eir
surf
ace.
H
ere,
the
cor
onav
irus
has
infe
cted
so
meo
ne w
hose
imm
une
syst
em c
an
reco
gnis
e S –
eith
er fro
m a
pre
viou
s in
fect
ion,
or
due
to v
acci
natio
n. N
ow,
the
muc
us in
the
ir a
irw
ays
cont
ains
an
tibod
ies
that
lock
on
to s
peci
ficsi
tes
on S
.
Onc
e th
e S p
rote
ins
are
boun
d to
an
tibod
ies
the
viru
s is
‘neu
tral
ised
’ –
it ca
n no
long
er b
ind
to o
ur c
ells
and
in
fect
us.
It
is n
o lo
nger
a t
hrea
t.