  An ultrametric model of epidemic spread of infections based on the classical
SIR model is proposed. Ultrametrics on a set of individuals based on theire
hierarchical clustering relativly to the average time of infectious contact is
introduced. The general equations of the ultrametric SIR model are written down
and their particular implementation using $p$-adic parameterization is
presented. A numerical analysis of the $p$-adic SIR model and a comparison of
its behavior with the classical SIR model are performed. The concept of
hierarchical isolation and the scenario of its management in order to reduce
the level of epidemic spread is considered.
