“…The corresponding deterministic systems of (27) and 28have a unique globally asymptotically stable endemic equilibrium (S * , I * ) = ( 6 5 , 2 5 ) and (S * , I * ) = ( 16 9 , 8 45 ), respectively (for more details, see for example [30]). From Figure 1, we see that in regime 1, the solution of (2) oscillates around the deterministic endemic equilibrium (S * , I * ) = ( 6 5 , 2 5 ) after some initial transients; in regime 2, the curve of susceptible population to (2) oscillates around the deterministic endemic equilibrium S * = 16 9 , and the disease I(t) of (2) with jumps is extinct eventually. Under regime-switching, however, the solution of (2) with parameters (29) is persistent and the curves of S(t) and I(t) of (2) oscillate in some appropriate region (see Figure 2).…”