“…SIR models on graphs with similar exchanges of infected individuals have previously been introduced in the literature [10,[14][15][16]20] with a particular emphasis on spreading properties. Actually, model (1.1) is at the crossroad of traditional reaction-diffusion models on graphs [11,23] and epidemic models that incorporate more sophisticated interactions dynamics [2,5,8,9,22,[26][27][28]. Note that in (1.1), we have assumed that only the infected population is subject to diffusion within the graph, and we think of S v being an ambient population whose movement does not affect its distribution.…”