In [KSb] we studied the following model for the spread of a rumor or infection: There is a “gas” of so-called A-particles, each of which performs a continuous time simple random walk on Zd , with jump rate DA . We assume that “just before the start” the number of A-particles at x, NA (x, 0−), has a mean μA Poisson distribution and that the NA (x, 0−), x ∈ Zd , are independent. In addition, there are B-particles which perform continuous time simple random walks with jump rate DB . We start with a finite number of B-particles.
