  We present a lattice gas cellular automaton (LGCA) to study spatial and
temporal dynamics of an epidemic of SIR (susceptible-infected-removed) type.
The automaton is fully discrete, i.e. space, time and number of individuals are
discrete variables. The automaton can be applied to study spread of epidemics
in both human and animal populations. We investigate effects of spatial
inhomogeneities in initial distribution of infected and vaccinated populations
on the dynamics of epidemic of SIR type. We discuss vaccination strategies
which differ only in spatial distribution of vaccinated individuals. Also, we
derive an approximate, mean-field type description of the automaton, and
discuss differences between the mean-field dynamics and the results of LGCA
simulation.
