Table 3.

Explanation of the parameters.

Parameter	Meaning
$A$	The influx of individuals into $S$
$\beta$	The transmission coefficient between
	compartments $S$ and $I$
$k$	The value of inhibitory effect
$\delta$	The natural death rate of $S$, $I$ and $R$
	compartments
$\gamma$	The rate of recovery from infection
$ϵ$	The disease-induced mortality rate