  An individual-based model of the infectious disease spread among the urban
population is considered. A system of stochastic equations, which describes
changes in quantities of four population groups, susceptible, exposed, infected
individuals and individuals in the state of remission, is built. The system of
equations of the model is supplemented with correlations, which consider
disease heaviness and duration for every infected individual. An algorithm and
a modelling program based on Monte-Carlo methods which allows to investigate
the group number dynamics is developed.
