An interview with Ezequiel Adamovsky, Doctor in history from University College London.
Historians generally attribute two major factors to this sudden “mass disappearance” of black Africans from the country – the deadly war against Paraguay from 1865-1870 (in which thousands of blacks fought on the frontlines for the Argentine military) as well as various other wars; and the onset of yellow fever in Buenos Aires in 1871.
What you see in the Streets are:Right, but you walk down the street in Buenos Aires and in a given day it would not be unusual not to see a single identifiably black person. Pretty much everyone is darker than I am, but essentially nobody looks black unless they're from somewhere else. But statistically, probably many of those non-black people you're seeing do indeed have African genes from the not to distant past!