Intracellular protozoan parasites and apoptosis: diverse strategies to modulate parasite-host interactions

Programmed cell death (apoptosis) is an important regulator of the host's r esponse during infection with a variety of intracellular protozoan parasite s. Parasitic pathogens have evolved diverse strategies to induce or inhibit host-cell apoptosis, thereby modulating the host's immune response, aiding dissemination within the host or facilitating intracellular survival. Here , we review the molecular and cell-biological mechanisms of the pathogen-in duced modulation of host-cell apoptosis and its effects on the parasite-hos t interaction and the pathogenesis of parasitic diseases. We also discuss t he previously unrecognized phenomenon of apoptotic cell death in (unicellul ar) protozoan parasites and its potential implications.