The asymptotic speed of propagation of the deterministic non-reducible n-type epidemic

A model has been formulated in 7] to describe the spatial spread of an epidemic involving n types of individuals, when triggered by the introduction of infectives from outside. Wave solutions for such a model have been investigated in 5] and 8] and have been shown only to exist at certain speeds. This paper establishes that the asymptotic speed of propagation, as denned in Aronson and Weinberger 1, 2], of such an epidemic is in fact c₀, the minimum speed at which wave solutions exist. This extends the known result for the one-type and host-vector epidemics.