  We examine how the behaviour of high degree vertices in a network affects
whether an infection spreads through communities or jumps between them. We
study two stochastic susceptible-infected-recovered (SIR) processes and
represent our network with a spatial preferential attachment (SPA) network. In
one of the two epidemic scenarios we adjust the contagiousness of high degree
vertices so that they are less contagious. We show that, for this scenario, the
infection travels through communities rather than jumps between them. We
conjecture that this is not the case in the other scenario, when contagion is
independent of the degree of the originating vertex. Our theoretical results
and conjecture are supported by simulations.
