First visceral leishmaniasis focus in Argentina.

An eight-year old boy from Posadas (27 masculine 23'S, 55 masculine 54'W) was diagnosed with visceral leishmaniasis (VL) during 2006. Lutzomyia longipalpis was discovered in the backyard of his house, while the spread of canine visceral leishmaniasis was confirmed in Posadas. This is the southernmost report of a VL transmission focus and the first in Argentina.