Chaos and biological complexity in measles dynamics.

Measles epidemiology offers a unique perspective on the construction of models to describe the dynamics of ecological systems. Simple models of measles transmission can generate deterministic chaos by various mechanisms. However, incorporating more biological realism into the model, in the form of age structure and realism in the seasonal forcing function, can suppress complex dynamics. Adding stochastic terms to the models restores complex dynamics, but raises new questions about demographic scale and population structure in these models.