Table 1 Definitions and values for model parameters

V/H

Number of tsetse flies (V) per human (H)

17

[15]

L/H

Number of NHA (L) per human (H)

1/6

[15]

H

Population size of Boffa East Mainland in 2008

14,500

Unpublished data

B _V

Tsetse constant birth rate

0.05/day

[15]

1/η _V

Duration of pupae stage in tsetse

20 days

[18]

\( {\mu}_{V_0} \)

Tsetse death rate without competition

0.030/day

[15]

\( {\mu}_{V_1} \)

Death rate competition parameter

0.0002

Assumed

1/σ _V

Susceptibility period in tsetse

1 day

[15]

a

Tsetse biting rate

0.333/day

[15]

β _VH

Probability of tsetse bite on human

See Table 2

Estimated

β _VL

Probability of tsetse bite on NHA

min(1-β _VH ,0.71)

[25]

1/τ _V

Incubation period in tsetse

25 days

[15]

μ _H

Human constant death rate

4.66e-05 /day

[34]

β _H

Transmission probability from tsetse to humans

See Table 2

Estimated

1/τ _H

Incubation period in humans

12 days

[15]

1/γ _H1

Stage I infectious period without treatment

526 days

[35]

1/γ _H2

Stage II infectious period without treatment

252 days

[36]

1/δ _H

Immune period in humans after treatment

50 days

[15]

β _L

Transmission probability from tsetse to NHA

See Table 2

Estimated

β _V

Transmission probability from humans/NHA to tsetse

0.2

[2, 15]

1/τ _L

Incubation period in NHA

12 days

[15]

1/γ _L

Infectious period in NHA

50 days

[15]

1/δ _L

Immune period in NHA

50 days

[15]

ϕ

Coverage of active surveillance

Varies

-

ρ

Probability that a HAT patients gets a positive CATT and then a positive antibody/Trypanolysis test

0.87

[1]

ε ₁

Efficacy of stage I treatment (pentamidine)

0.94

[37]

ε ₂

Efficacy of stage II treatment (nifurtimox-eflornithine)

0.965

[38]

ζ

Treatment seeking rate of stage II patients

See Table 2

Estimated

p

Probability of death due to stage II treatment failure (nifurtimox-eflornithine)

0.007

[38]