•    

• Metacommunity structure• Landscape heterogeneity• Environmental filtering• Dispersal

• Metacommunity structure• Landscape heterogeneity• Environmental filtering• Dispersal

• Between-species heterogeneity• Reservoir-target host dynamics• Zoonoses/emerging infectious diseases

• Host-parasite dynamics• Transmission• Superspreaders• Critical community size R0

• Parasite–immune system interactions• Parasite-parasite interactions• Disease progression

Regional-to-community

scaling

Community-to-localscaling

Within- tobetween-

host scaling

Within-host

Between-host

Between-species

Regional

• Competition (exploitation, interference, apparent)• Predator-prey dynamics

• Metapopulation dynamics

Parasite species

Disease ecology Community ecology

DispersalEstablishmentColonization

(amongcommunitiesand regions)

DispersalEstablishmentColonization

(amongindividuals

andpopulations)

• • 

• 

• • • 

• 

• 

Global network:linked by shared

immune response

Local network:(e.g., blood), linkedby parasite iden�ty

and resources

Local network:(e.g., GI), linked bylocalized immunity,

resources, andparasite iden�ty

10.

2.

6.

4.

5. 7.

3.

9.

8.

1.

TRENDS in Parasitology

• • • • 

• 

• • 

• • 

• • • • • • 

0 1 2 3 40%5%

10%15%20%25%30%35%

Wet

lands

Parasite richness BdRa

navir

us

Ribe

iroia

Echin

ostom

es

0%

20%

40%

60%

80%

100%

Wet

lands

None Rib

Echino Bd RV

Rib+E

Rib+B

Rib+RV E+B

E+RV

B+RV

Rib+E+B

Rib+E+RV

Rib+B+RV

E+B+RV

Rib+E+B+RV

0%5%10%15%20%25%30%35%

Wetlan

ds

0 1 2 3 40%

10%

20%

30%

40%

50%

Indiv

iduals

Parasite richness BdRa

navir

us

Ribe

iroia

Echin

ostom

es

0%

10%

20%

30%

40%

50%

Infe

cted

indivi

duals

None Rib

Echin

o Bd RVRi

b+E

Rib+

BRi

b+RV E+

BE+

RVB+

RVRi

b+E+

BRi

b+E+

RVRi

b+B+

RVE+

B+RV

Rib+

E+B+

RV

0%

5%

10%

15%

20%

25%

Infe

cted

indivi

duals

• • 

• • 

Longer infection duration

Higher host mortality

More infectious propagules

Less infectious propagules

Between-Host e.g., transmission

Increased transmission (coinfection causes parasites to

spread more rapidly through host population)

Decreased transmission (coinfection leads to decreased

success of one or more parasites)

Effect on transmission

Within-Host e.g., infection and pathology

Pathogen interaction Effect on infection

Facilitation (e.g., immunity tradeoffs

or suppression)

Antagonism (e.g., competition or

predation)

Neutral

Increase (more of 1 or both

parasites)

Decrease (less of 1or both

parasites)

No change

• • • • 

• • • 

• – 

• – 

Ranavirus

Hyla versicolor

1 2 Echinoparyphium

1 2

Day 0

Day 5

Day 10

Day 0

Day 0

Takedown

Takedown

Takedown

14 days

14 days

14 days

0 or 103 PFUs of virus mL-1

0 or 50 Echinoparyphium

Ranavirus

Response Variables AnalysesSurvival Wilcoxon-Gehan TestRanavirus prevalence Fisher’s Exact TestRanaviral load Mann-Whitney U testEchinoparyphium infection Two-way ANOVA

0 1 2 3 4 5 6 7 8 9 10 11 12 13 140

20

40

60

80

100

Surv

ival

(%)

Days post ranavirus exposure

Control

Trematode

Ranavirus

Trematode+Ranavirus

Ranavirus exposure at day 0Wilcoxon-Gehan=37.1

p=0.001

0 1 2 3 4 5 6 7 8 9 10 11 12 13 140

20

40

60

80

100

Surv

ival

(%)

Days post ranavirus exposure

Control

Trematode

Ranavirus

Trematode+Ranavirus

Ranavirus exposure at day 5Wilcoxon-Gehan=21.3

p=0.001

0 1 2 3 4 5 6 7 8 9 10 11 12 13 140

20

40

60

80

100

Surv

ival

(%)

Days post ranavirus exposure

Control

Trematode

Ranavirus

Trematode+Ranavirus

Ranavirus exposure at day 10Wilcoxon-Gehan=17.4

p=0.001

*25%

0 5 10 0 5 100

20

40

60

80

100

Rana

virus

pre

vale

nce

(%)

Day of ranavirus exposureNo trematode Trematode

N = 60Mean Rank = 51.60

EchinoparyphiumNo Echinoparyphium

16 12 8 4Frequency

0

0.9

1.8

2.7

3.6

4.5

5.4

N = 55Mean Rank = 64.98

Log

(Vira

l load

)

0 4 8 12 16

Log (Viral load)

0

0.9

2.7

3.6

4.5

5.4

100%100%100%64%67%20%

N = 60Mean Rank = 51.60

N = 55Mean Rank = 64.98

100%80%

40%

SurvivedDid not survive

1.8

100%

29%67%

0 5 10 0 5 100

10

20

30

40

50

Tre

ma

tod

es e

ncyste

d (

%)

Day of ranavirus exposure

No virus Virus

• 

• • 

• 

• • • 

A. americanus H. versicolor L. pipiens P. crucifer

0

20

40

60

80

100

Surv

ival (

%)

C E V EV C E V EV C E V EV C E V EV

49% 42% 27% 22%

A. americanus H. versicolor L. pipiens P. crucifer

0102030405060708090

100

Infe

ction

pre

valen

ce (%

)

NE NE NE NEE E E E

A. americanus H. versicolor L. pipiens P. crucifer

0

0.5

1

1.5

2

2.5

3

Log

viral

load

NE NE NE NEE E E E

19% 27%

28%

A. americanus H. versicolor L. pipiens P. crucifer

0

4

8

12

16

20

Ency

sted

Echin

opar

yphiu

m

NV NV NV NVV V V V

• 

• • 

•