Numerics of population balance equations in biology

In my field of research I deal with the evolution of distributed quantities in epidemiology. The underlying mathematical model is complex and consists of ordinary, partial differentials and integral terms. I want to develop a convergent numerical scheme solving a weakly coupled system of those partial integro differential equations approximately. Beginning with a testcase of 2 independent variables / characterics of such an evolution process it will be the aim to deal with a high dimensional model later on.