The objective of this study was to establish and follow a prospective cohort of individuals at risk for ZCL, living in endemic areas of L. major transmission with varying infection prevalence, evaluate markers of exposure to Leishmania infection (LST and scar presence), analyze IFN-γ, IL-10, and GrB levels in in vitro PBMC cultures, estimate the incidence of ZCL after the transmission season, and ultimately identify immunological markers associated with resistance or susceptibility to the infection. The gene discussed is IL10; the disease is infection.