The first section of this chapter explores corruption, modelled as a non-fatal transmissible infection which divides a community into 4 compartments: Susceptible, Infective, Removed and Resistant. The Removed class has age structure. The corruptionfree steady state, though unstable, can be stabilized by feedback control. The efficiency of the measure depends on a number of parameters, especially the rates at which susceptibles become resistant, and the infective are removed or become resistant. The second part analyses disease transmission as a saturable interaction. The use of the concept of saturable interactions as a framework for modelling disease transmission is explored with two SIS cases. In both cases, it is found.
