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THE
ECOLOGY
OF TIMING
IN HOST-
PARASITE
INTERACTIONS
Probing The Particulars
Of Periodicity In
Plasmodium Parasites
Aidan O’Donnell
Nicole Mideo
Sarah Reece
Artificial Biological Clock by Cohen Van Balen
~24 hours
Artificial Biological Clock by Cohen Van Balen O’Donnell et al 2011 Proc. R. Soc B.
0
1
2
3
Reversed Cycle Normal Cycle
Mismatched Matched
Pa
rasi
te d
en
sity
x 1
09
/ m
l
Reversed Light Room Normal Regime Room
Artificial Biological Clock by Cohen Van Balen
0
1
2
3
Ring Troph
Matched Mismatched
0
1
2
3
IV IP
Matched Mismatched
Stage Route
2013
Pa
rasi
te d
en
sity
x 1
09 /
ml
O’Donnell et al 2011 Proc. R. Soc. B
0
1
2
3
Reversed CycleNormal Cycle
Mismatched Matched
Reversed Room Normal Room
Pa
rasi
te d
en
sity
x 1
09
/ m
l
0
2
4
6
8
10
1 2 3 4 5 6 7
pa
rasi
te d
en
sity
(x10
8 m
l-1)
Day post infection
Matched MisMatched
0
1
2
3
4
5
1 2
pa
rasi
te d
en
sity
(x10
5 m
l-1)
Infection
control
measure?
Barrier to
infection?
Timing matters in host
Timing & transmission
Does timing matter to
the mosquito?
Indirect consequences
to parasites?
What are
the fitness
consequences
of timing
to mosquitos?
Activity of An. stephensi
Rowland (1989) Physiol Entomol
Expected Unexpected
Drosophila:
Periodicity in
susceptibility to
infection Stone (2012) PLoS Pathog.
7pm 7pm 7am 7am 1pm 1pm 1am
GMT
Evening feed 8pm
Morning feed 10am
Rowland (1989) Physiol Entomol
0
5
10
Matched Mismatched
Cu
mu
lative
pa
rasi
te d
esn
ity
(x 1
08 m
l-1)
P. berghei p = 0.75
0
50
100
150
200
250
Evening Morning
Evening
Morning
Oocysts
p = 0.15
Proportion infected :
~95% infection success
No difference between Eve/Morn
(p = 0.56)
Oo
cyst
de
nsi
ty
0
20
40
60
80
control infected
me
an
clu
tch
siz
e
Clutch size
Reduced fecundity in
Infected mosquitos
No effect of timing
21 = 5.12; P = 0.0271
Time: 21 = 3.39; P = 0.06567
Treatment: 21 = 5.46; P = 0.01944
0.0
0.2
0.4
0.6
0.8
evening morning
pro
po
rtio
n la
yin
g e
gg
s
control infected
Proportion that laid
Timing effects likelihood to
lay
Infection reduces likelihood to
lay
0.0
0.1
0.2
0.3
0.4
0.5
evening morning
Pro
po
rtio
n t
ha
t la
y
control
infected
First day of egg lay (day 5)
F(1,16) = 17.10; P = 0.0008
Morning fed
mosquitos lay as
soon as they can
0.0
0.2
0.4
0.6
0.8
evening morning
Pro
po
rtio
n t
ha
t la
y
control infected
F(1,18) = 7.70; P = 0.013
Egg lay day 8+
Overall, uninfected
mosquitos more
likely to lay & lay
later
-No difference in mortality
of inf vs. uninf when no
egg lay
-Increased longevity
through reduced
fecundity
Morning infected
Investing in
Immediate
reproduction
Vézilier (2012) Proc. R. Soc. B
Timing matters directly to parasites
in the host
Timing also matters indirectly through its effect on mosquitos
Transmission
potential could
depend on when
the vector is infected
Mosquito
adaptation
to bed-nets
Parasite
adaptation
to timing
-Moiroux (2012) J Infect Dis.
-Charlwood (1987) Med. Vet. Entomol.
Thank you for listening
Reece Group
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