Fig. 6.

Corresponding population numbers of solution $\left(S\right(t),V(t),I(t\left)\right)$ to system (1.3) with random perturbations $({\sigma }_1,{\sigma }_2,{\sigma }_3)=(0.01,0.01,0.78)$ and main parameters $(\Lambda ,\beta ,\mu ,\alpha ,\delta ,\gamma ,\vartheta )=(0.8,0.4,3\times {10}^{-5},0.00457,0.13,0.2,0.38)$.