Modern theory on the dynamics of infectious diseases is infl uenced by ecological theory, especially by demography. Th e study of these dynamics using mathematical models has had a staggering development in recent years, and has proven to be a valuable tool to understand epidemiological patterns and processes, provided that models are as close as possible to real life situations and based on biological knowledge. We discuss the basic concepts of the transmission dynamics of infectious agents aff ecting a host and an insect vector. We specifi cally study mathematical models for the dynamics of human malaria in both spatially homogeneous and fragmented environments. Models for the dynamics of human onchocerciasis are also presented. Finally we discuss the results and their basic and applied importance.