New biomarkers are needed for monitoring the effectiveness of treatment for visceral leishmaniasis (VL). They might also improve the detection of the asymptomatic population in Leishmania-endemic areas. This paper examines the IL-2, IFN-γ, IFN-γ-induced protein 10 (IP-10), and monokine-induced-by-IFN-γ (MIG) levels in whole blood—stimulated in vitro with soluble Leishmania antigen (SLA)—taken from asymptomatic individuals and patients treated for VL living in a post-outbreak (Leishmania infantum) area in Spain, and in an endemic (Leishmania donovani) area of Bangladesh. IP-10 was found to be an accurate global marker of asymptomatic subjects with positive cellular/humoral tests, while MIG was found to be a better marker of contact with L. donovani than IL-2 but no for those with L. infantum. Determining IP-10, MIG, and IFN-γ levels proved useful in monitoring the cellular immune response following treatment for active disease caused by L. infantum.