Our studies concentrate on the obligate intracellular parasite Trypanosoma cruzi, the cause of a chronic debilitating disease (Chagas' disease) that afflicts millions of people world-wide. In the central nervous system, T. cruzi invades a variety of cell types, including astrocytes, microglia, and neurons. T. cruzi infection of the brain of immunologically competent individuals is of short duration, and causes no symptoms or pathology despite the induction of strong inflammatory response. We have found that T. cruzi encodes mimics of neurotrophic factors that potently activate neuron and glial cell survival and regeneration. One of these mimics, called parasite-derived neurotrophic factor (PDNF) activates neurotrophin receptors TrkA and TrkC, resulting cell survival and parasite invasion. The potent induction of neuroprotective mechanisms by PDNF is being exploited as drug development for neurodegenerative diseases such as Huntington's disease, Parkinson's disease, and Alzheimer's disease.