Some studies in experimental models of infection of T. cruzi suggest that the potent immune response to Th-1 CD4 and CD8 cells, with the production of specific inflammatory cytokines, such as interferon gamma (IFN-γ), tumour necrosis factor (TNF-α), and interleukin 12 (IL-12), as well as the production of reactive nitrogen species such as nitric oxide (NO), plays an important role in the control of parasitemia during the initial stage of the disease [4, 10–13]. This evidence concerns the gene IFNG and parasitic infectious disease.