Infectious diseases, in spite of antibiotic and other treatments, remain one of the biggest medical problems to date. The overall problem of understanding host-parasite dynamics is extremely important, as it is intrinsic to the study of infection at all organismal scales. Many examples of such host-parasite systems exist, with debilitating and/or fatal consequences for humans all over the planet; malaria, schistosomiasis, and Chagas' Disease, for example. Because of its complex life-cycle, T. cruzi provides one of the most fascinating and complex, yet sophisticated initial model systems for investigation. Our methodology is based upon an integrated mathematical, in silico modeling approach that is directly coupled to biological experimentation. The long-term goal of this project is to apply novel mathematical and computational modeling technologies, well informed by biological experimentation, to specific host-parasite systems in order to develop new paradigms for understanding the infectious disease process, for the purpose of developing new therapeutic and public health interventions and strategies. Towards these goals, we are developing and will make available to the scientific community an extensible, portable, in silico, multi-scale, high performance computational model of parasite-host dynamics and use that model to study effective strategies for managing the host-vector and parasite dynamics of the T. cruzi parasite, the causal agent in Chagas' Disease. This modular environment will allow other users to create "parasite modules" for such parasites and microbes as E. histolytica and the potential bioterrorism agents like C. parvum (for which there is no treatment).