  In this paper, we perform Monte Carlo calculations to study the critical
behavior of the spread of infectious diseases through a novel approach to the
SIR epidemiological model. A stochastic lattice gas version of the model was
applied on hybrid lattices which, in turn, are generated from typical square
lattices when inserting a connection probability $p$ that a given lattice site
has both first- and second-nearest neighbor interactions. By combining
percolation theory and finite-size scaling analysis, we estimate both the
critical threshold and leading critical exponent ratios of the non-absorbing
SIR model in different cases of hybrid lattices. An analysis of the average
size of the percolating cluster and the size distribution of non-percolating
clusters of recovered individuals was carried out to determine the universality
class of the model.
