“…On the other hand, there is no traveling wave solution for (1.2) when βS 0 ≤ γ. There are substantial recent developments on the existence and non-existence of traveling wave solutions for Kermack-Mckendrick SIR model, see [1,2,7,12,17,19,20,24,25,27,28] and references therein. In particular, Wang and Wang [17] introduced the following general diffusive Kermack − γI(t, x) − δI(t, x), ∂ ∂t R(t, x) = d 3 ∆R(t, x) + γI(t, x), (1.3) in which N = S + I + R is the total population, d 1 , d 2 and d 3 are the diffusion rates of the susceptible (S), infective (I) and recovered (R) individuals, respectively.…”