Table 1 Description of model parameters and ranges used in the Latin hypercube parameter sets. All parameter values correspond to Schistosoma mansoni and Biomphalaria glabrata

m

Maximum number of snails in the environment

5000–20,000

Estimated

c

Liters of water in the environment

1000–100,000

Estimated

l₂

Reduced rate of maturation in infected neonates/juveniles

0.714 of maturation rate in uninfected neonates/juveniles

[35, 38]

l₃

Averaged reduced rate of maturation in infected snails in the combined neonate/juvenile/small adult class

0.75 of maturation rate in uninfected snails

[35, 38]

w₁

Average time to mature from neonate to juvenile

7 weeks

[35, 38, 51]

w₂

Average time to mature from juvenile to small adult

5 weeks

[35, 38, 51]

w₃

Average time to mature from small adult to large adult

2 weeks

[35, 38, 51]

1/d_m

Lifespan of miracidia

4–16 h

[10]

1/d_c

Lifespan of cercariae

8–20 h

[10]

u₁

Mortality rate of uninfected neonatal snails

0.007–0.152/week

[35, 36]

u₂

Mortality rate of infected neonatal snails

0.062–0.607/week

[35, 36]

u₃

Mortality rate of uninfected juvenile snails

0.007–0.152/week

[35, 36]

u₄

Mortality rate of infected juvenile snails

0.062–0.607/week

[35, 36]

u₅

Mortality rate of uninfected small adult snails

0.007–0.152/week

[35, 36]

u₆

Mortality rate of infected small adult snails

0.062–0.607/week

[35, 36]

u₇

Mortality rate of uninfected large adult snails

0.007–0.152/week

[35, 36]

u₈

Mortality rate of infected large adult snails

0.062–0.607/week

[35, 36]

1/u₉

Lifespan of humans

60 years

[48]

f₁

Fecundity of susceptible small adult snails

40/week

[26, 29, 30, 46, 49]

f₂

Fecundity of exposed small adult snails

4.77/week

[5, 29, 46, 49, 50]

f₃

Fecundity of infected but not castrated snails

4.77/week

[5, 29, 30, 46, 49, 50]

f₄

Fecundity of susceptible large adult snails

40/week

[5, 29, 30, 46, 49, 50]

f₅

Fecundity of exposed large adult snails

4.77/week

[5, 29, 30, 46, 49, 50]

f₆

Fecundity of infected but not castrated adult snails

4.77/week

[5, 29, 30, 46, 49, 50]

f₇

Weighted average fecundity of susceptible snails in the combined neonatal/juvenile/small adult class

13.33/week

[5, 29, 30, 46, 49, 50]

f₈

Weighted average fecundity of exposed or infected but not castrated snails in the combined neonatal/juvenile/small adult class

1.59/week

[5, 29, 30, 46, 49, 50]

g

Castration rate of snails

0.1667/week

[46]

1/y

Prepatent period in snails

18–45 days

[39]

e₁

Exposure rate of neonatal snails to miracidia

50–150/week

Estimated

e₂

Exposure rate of juvenile snails to miracidia

50–150/week

Estimated

e₃

Exposure rate of small adult snails to miracidia

50–150/week

Estimated

e₄

Exposure rate of large adult snails to miracidia

50–150/week

Estimated

p₁

Per parasite susceptibility for neonatal snails

0–1

[5, 51, 52]

p₂

Per parasite susceptibility for juvenile snails

0–1

[5, 51, 52]

p₃

Per parasite susceptibility for small adult snails

0–1

[5, 51, 52]

p₄

Per parasite susceptibility for large adult snails

0–1

[5, 51, 52]

s₁

Shedding rate of neonatal snails

2800/week

[29, 43]

s₂

Shedding rate of juvenile snails

5500/week

[29, 43]

s₃

Shedding rate of small adult snails

6000/week

[29, 43]

s₄

Shedding rate of large adult snails

6800/week

[29, 43]

s₅

Averaged shedding rate in combined neonatal/juvenile snail class

3925/week

[29, 43]

s₆

Averaged shedding rate in combined small/large adult snail class

6774/week

[29, 43]

s₇

Averaged shedding rate in combined neonatal/juvenile/small adult snail class

4925/week

[29, 43]

b

Snail-to-human transmission rate

0.00001–0.001/week

Estimated

h_w

Probability of eggs reaching water and hatching

0–1

[27, 39, 51]

q₁

Recovery rate among lightly infected humans

0.2–0.333/year

[39]

q₂

Recovery rate among moderately infected humans

0.2–0.333/year

[39]

q₃

Recovery rate among heavily infected humans

0.2–0.333/year

[39]

1/l_h

Latent period in humans

25–30 days

[39]

v₁

Proportion of infected humans who are lightly infected

0–1

Estimated

v₂

Proportion of infected humans who are moderately infected

0–1

Estimated

v₃

Proportion of infected humans who are heavily infected

0–1

Estimated

g₁

Eggs produced by a lightly infected human

7000/week

[39, 53]

g₂

Eggs produced by a moderately infected human

28000/week

[39, 53]

g₃

Eggs produced by a heavily infected human

70000/week

[39, 53]

g₄

Eggs produced per mated female schistosome

350 /day

[54]

i

Grams of feces produced per human

200/day

[55]

N_h

Total human population size

200

Estimated

z

Scaling parameter

1–10

Estimated

k

Worm aggregation constant

0.24

[51]