In spite of the presence of effector molecules such as IFN-γ, TNF-α and NO during active disease, the parasite persists, implying that the biological processes involved in the disease pathogenesis are complex and cannot be interpreted as simple T helper 1 (Th1) or Th2-mediated processes, characteristics of the murine model of leishmaniasis. Here, IFNG is linked to leishmaniasis.