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Theory and Modern Applications

Table 2 Syphilis model parameters notation and values

From: Mathematical analysis and optimal control interventions for sex structured syphilis model with three stages of infection and loss of immunity

Parameters

Description

Values

Source

\(\pi _{m}\)

Recruitment rate into susceptible male population

0.3

[29]

\(\pi _{f}\)

Recruitment rate into susceptible female population

0.45

[29]

\(\alpha _{f}\)

Transmission probability of female with syphilis infection

0.2

[15]

\(\alpha _{m}\)

Transmission probability of male with syphilis infection

0.5

[15]

\(\gamma _{m}\)

Progression rate from male with primary syphilis to male with secondary syphilis infection

0.01

[15]

\(\gamma _{f}\)

Progression rate from female with primary syphilis

0.627

[15]

ψ

Average number of sexual partner per unit time to female with secondary syphilis infection

2

[19]

\(\beta _{m}\)

Progression rate from male with secondary syphilis to male with latent syphilis infection

0.618

[15]

\(\beta _{f}\)

Progression rate from female with secondary syphilis to female individual with latent syphilis infection

0.618

[15]

\(\varphi _{m}\)

Rate of recovery from syphilis in infectious male

0.1

[29]

\(\varphi _{f}\)

Rate of recovery from syphilis in infectious female

0.1

[29]

\(\sigma _{m_{1}}\)

Treatment rate of male with primary stage syphilis

0.05

[29]

\(\sigma _{m_{2}}\)

Treatment rate of male with secondary stage syphilis

0.1

[29]

\(\sigma _{m_{3}}\)

Treatment rate of male with latent stage syphilis

0.2

[29]

\(\rho _{f_{1}}\)

Treatment rate of female with primary stage syphilis

0.05

[29]

\(\rho _{f_{2}}\)

Treatment rate of female with secondary stage syphilis

0.1

[29]

\(\rho _{f_{3}}\)

Treatment rate of female with latent stage syphilis

0.2

[29]

μ

Rate of natural death

5.48 × 10−5day−1

[42]

\(A_{1}\)

Weight coefficients for both infectious male and female syphilis

31

[38]

\(B_{1}\)

Relative cost for prevention and treatment in male and female individuals

0.5

[38]

\(B_{2}\)

Relative cost for prevention and treatment in male and female individuals

0.4

Assumed

\(B_{3}\)

Relative cost for prevention and treatment in male and female individuals

0.3

Assumed