Classical Swine Fever Decoding infection and Transmission Dynamics
Pig–pig, pig–wild boar interaction with vaccination, biosecurity, mechanical transmission, and culling.
Model Architecture
Differential Equations
Pigs
$$ \begin{aligned} \frac{dS_p}{dt} &= b_p + \varepsilon_1 V_p - \Big[ \frac{\beta_P I_p}{N_p} + \frac{\beta_{WP} I_w}{N_w} + \frac{\beta_1 (S_1+F) I_p}{N_p} \Big](1-\mu_1)S_p f(\cdot) - \phi_1 S_p - \mu_p S_p \\ \frac{dE_p}{dt} &= \Big[ \frac{\beta_P I_p}{N_p} + \frac{\beta_{WP} I_w}{N_w} + \frac{\beta_1 (S_1+F) I_p}{N_p} \Big](1-\mu_1)S_p f(\cdot) - (\sigma_1+\mu_p)E_p \\ \frac{dI_p}{dt} &= \sigma_1 E_p - (\gamma_1 + C + d_1)I_p \\ \frac{dR_p}{dt} &= \gamma_1 I_p - \mu_p R_p + \theta_1 V_p \\ \frac{dV_p}{dt} &= \phi_1 S_p - (\varepsilon_1+\theta_1+\mu_p)V_p \end{aligned} $$Wild Boar
$$ \begin{aligned} \frac{dS_w}{dt} &= b_w - \frac{\beta_{PW} I_p}{N_p}(1-\pi)S_w f(\cdot) - \mu_w S_w - \pi S_w \\ \frac{dI_w}{dt} &= \frac{\beta_{PW} I_p}{N_p}(1-\pi)S_w f(\cdot) - (\gamma_2 + d_2 + \mu_w)I_w \\ \frac{dR_w}{dt} &= \gamma_2 I_w + \pi S_w - \mu_w R_w \end{aligned} $$Equation Parameterization
| SL No | Parameter | Description |
|---|---|---|
| 1 | b_p | Birth rate of pigs |
| 2 | b_w | Birth rate of wild boar |
| 3 | beta_P | Pig → pig transmission rate |
| 4 | beta_W | Wild boar → wild boar transmission rate |
| 5 | beta_{WP} | Wild boar → pig transmission (swill, vehicles, carcasses) |
| 6 | beta_{PW} | Pig → wild boar transmission |
| 7 | beta_1 | Mechanical transmission (humans, vehicles, tools, clothes, shoes, swill feeding) |
| 8 | S_1 | Swill feeding rate |
| 9 | F | Fomite contamination index |
| 10 | mu_1 | Biosecurity effectiveness (0–1) |
| 11 | mu_P | Natural mortality rate of pigs |
| 12 | mu_w | Natural mortality rate of wild boar |
| 13 | d_1 | Disease-induced death rate of pigs |
| 14 | d_2 | Disease-induced death rate of wild boar |
| 15 | varepsilon_1 | Immunity loss rate in vaccinated pigs |
| 16 | phi_1 | Vaccination rate of susceptible pigs |
| 17 | sigma_1 | Rate exposed pigs become infected |
| 18 | theta_1 | Recovery after vaccination |
| 19 | gamma_1 | Recovery rate of pigs |
| 20 | gamma_2 | Recovery rate of wild boar |
| 21 | C | Culling rate |
| 22 | f(T) | Temperature effect |
| 23 | f(pH) | pH effect |
| 24 | f(RH) | Relative humidity effect |
| 25 | f(R) | Rainfall effect |
| 26 | pi | Rate of bait vaccination for wild boar |