Fig. 6.

The color-coded values of total proportion of infected individuals who are recovered or dead at the end of the epidemic spreading in the parameter plane $(\alpha ,m)$. m is the strength of control measures and is unchanged with time. The red asterisks indicate the value of $m_c$ with different $\alpha$ according to Eq. (3). The spreading probability is a $\beta =0.3$ and b $\beta =0.5$. The values of other parameters are set as: ${\gamma }_1=\frac{1}{21}$, ${\gamma }_2=\frac{1}{10}$, ${\gamma }_3=\frac{1}{15}$, $\delta =0.03$, $l=0$