This work is funded through the Professional Opportunities for Women in Research and Education (POWRE) program as a Research/Educational Enhancement Project. This proposal concerns with both research and educational activities in mathematical biology. The research project focuses on the use of differential equations and dynamical systems theory to study the role of heterogeneity on the dynamics of infectious diseases and host-parasite interactions. Two particular host-parasite systems are used: the human-tuberculosis (microparasitic) and the human-schistosome-snail (macroparasitic) to highlight the generality of our approaches in the study of host-parasite interactions. This project will look at: the impact that the host heterogeneity in infectivity has on the coexistence and coevolution of competing strains of TB -- regular TB and drug resistant TB strains; the effect that the long and variable latency period of TB has on the evolution of parasite virulence; and to study how control programs of macroparasites (schistosomiasis) affect parasite genetic diversity. In spite of the long and lasting connection among many fields of mathematics and biology, few students have sufficient training to work effectively at the interface of these fields. The educational project centers on introducing courses in mathematical biology at both undergraduate and graduate levels at my home institution. Such courses are currently non-existent at Purdue University. This project consists of developing curricula for the two courses, preparing lecture notes and designing research projects suitable for Purdue students, as well as teaching these courses. Both courses will be designed for students majoring in either mathematics or biology. The goal of these educational activities is to give students experience in interdisciplinary studies, as well as in mathematical biology, thus strengthening their backgrounds and making them more versatile for employment. This award is funded through the MPS Office of Multidisciplinary Activities (OMA).