  Motivated by our intention to use SIR-type epidemiological models in the
context of dynamic networks as provided by large-scale highly interacting
inhomogeneous human crowds, we investigate in this framework possibilities to
reduce the classical SIR model to a representative evolution model for a
suitably chosen observable. For selected scenarios, we provide practical {\em a
priori} error bounds between the approximate and the original observables.
Finally, we illustrate numerically the behavior of the reduced models compared
to the original ones.
