Visceral leishmaniasis (VL), caused by Leishmania infantum (syn. chagasi), is expanding at an alarming rate in Argentina. In Argentina, VL was first diagnosed in the Northeastern province of Misiones in May 2006,1 with previous reports recording this infection in the neighboring Paraguay much earlier. Since its first diagnosis in Argentina, thousands of cases in dogs and over 100 cases (many fatal) in humans have been diagnosed in several regions of the north and northeastern provinces of Argentina (Figure 1).2,3 The disease has traveled over 1000 km, and so has its vectors and main reservoir, ...