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Nipah Virus Disease (NiV)
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Decoding of Infection and Transmission Dynamics

This section contains: Model architecture, Differential equations, and Equation parameterization.

Model Architecture

Nipah Model Architecture

Differential Equations

Fruit Bats (SIR)

$$ \begin{aligned} \frac{dS_B}{dt} &= \psi_B - \mu_B S_B - \left(\beta_B \frac{F I_B + I_B}{N_B}\right) S_B \, f_t f_h, \\ \frac{dI_B}{dt} &= \left(\beta_B \frac{F I_B + I_B}{N_B}\right) S_B \, f_t f_h - \mu_B I_B - \gamma_B I_B, \\ \frac{dR_B}{dt} &= \gamma_B I_B - \mu_B R_B. \end{aligned} $$

Intermediate Hosts (Pigs/Cattle/Cats/Dogs/Rodents/Horses) (SEIR)

$$ \begin{aligned} \frac{dS_I}{dt} &= \psi_I - \mu_I S_I - \Bigg[\beta_{BI}\left(\frac{F I_B + I_B}{N_B}\right) f_t f_h + \beta_I \left(\frac{I_I}{N_I}\right)\Bigg] S_I, \\ \frac{dE_I}{dt} &= \Bigg[\beta_{BI}\left(\frac{F I_B + I_B}{N_B}\right) f_t f_h + \beta_I \left(\frac{I_I}{N_I}\right)\Bigg] S_I - \mu_I E_I - \rho_I E_I - \sigma_I E_I, \\ \frac{dI_I}{dt} &= \rho_I E_I - (\gamma_I + \omega) I_I - (\delta_I + \mu_I) I_I, \\ \frac{dR_I}{dt} &= (\gamma_I + \omega) I_I + \sigma_I E_I - \mu_I R_I. \end{aligned} $$

Humans (SEIR)

$$ \begin{aligned} \frac{dS_H}{dt} &= \psi_H - \mu_H S_H - \Bigg[\beta_{BH}\left(\frac{F I_B + I_B}{N_B}\right) f_t f_h + \beta_I \left(\frac{I_I}{N_I}\right) + \beta_H \left(\frac{k I_H + (1-k) I_H}{N_H}\right)\Bigg](1-\theta \pi \varepsilon)\, S_H, \\ \frac{dE_H}{dt} &= \Bigg[\beta_{BH}\left(\frac{F I_B + I_B}{N_B}\right) f_t f_h + \beta_I \left(\frac{I_I}{N_I}\right) + \beta_H \left(\frac{k I_H + (1-k) I_H}{N_H}\right)\Bigg](1-\theta \pi \varepsilon)\, S_H - \rho_H E_H - \mu_H E_H - \sigma_H E_H, \\ \frac{dI_H}{dt} &= \rho_H E_H - (\gamma_H + \alpha) I_H - (\delta_H + \mu_H) I_H, \\ \frac{dR_H}{dt} &= (\gamma_H + \alpha) I_H + \sigma_H E_H - \mu_H R_H. \end{aligned} $$

Equation Parameterization

Sl. No Parameter Description
1 S_B Susceptible population of bats
2 I_B Infected population of bats
3 R_B Recovered population of bats
4 S_I Susceptible population of intermediate hosts
5 E_I Exposed population of intermediate hosts
6 I_I Infected population of intermediate hosts
7 R_I Recovered population of intermediate hosts
8 S_H Susceptible population of humans
9 E_H Exposed population of humans
10 I_H Infected population of humans
11 R_H Recovered population of humans
12 N_B Total bat population
13 N_I Total intermediate-host population
14 N_H Total human population
15 k Proportion of superspreaders among infected humans
16 F Food contaminated by bat saliva/blood/urine (contamination factor/index)
17 β_B Transmission rate in bats
18 β_I Transmission rate in intermediate hosts (within-host group)
19 β_H Transmission rate in humans (within-human group)
20 β_BI Transmission from bats to intermediate hosts
21 β_BH Transmission from bats to humans
22 γ_B Recovery rate of bats
23 γ_I Recovery rate of intermediate hosts
24 γ_H Recovery rate of humans
25 σ_I Additional exposure progression rate (intermediate hosts)
26 σ_H Additional exposure progression rate (humans)
27 ρ_I Progression rate from exposed to infected (intermediate hosts)
28 ρ_H Progression rate from exposed to infected (humans)
29 ψ_B Inclusion/recruitment rate of bats
30 ψ_I Inclusion/recruitment rate of intermediate hosts
31 ψ_H Inclusion/recruitment rate of humans
32 μ_B Natural death rate of bats
33 μ_I Natural death rate of intermediate hosts
34 μ_H Natural death rate of humans
35 δ_I Disease-induced death rate of intermediate hosts
36 δ_H Disease-induced death rate of humans
37 f_t Environmental modifier: temperature factor
38 f_h Environmental modifier: relative humidity factor
39 ω Treatment effect on infected pigs (intermediate hosts)
40 θ Enhanced personal hygiene due to public enlightenment
41 ε Rate of public enlightenment
42 π Surveillance coverage
43 α Treatment effect on infected humans