  An epidemic model where disease transmission can occur either through global
contacts or through local, nearest neighbor interactions is considered. The
classical SIR--model describing the global interactions is extended by adding
additional equations for the density of local pairs in different epidemic
states. A locality parameter $p\in [0,1]$ characterizes the probability of
global or local infections. The equilibria of the resulting model are analyzed
in dependence of the locality parameter and the transmission rate of the
pathogen. An explicit expression for the reproduction number in terms of the
locality parameter and the disease parameters is obtained. Transient
simulations confirm these findings. Neighboring pairs of one infected and one
susceptible can be considered as active pairs, since local transmission of the
disease can only occur in that situation. Our analysis shows, that the fraction
of active pairs is minimal for intermediate values of the locality parameter.
