The ghost children are those who, like the street children of Cusco, sell cheap wares from baskets, sleep in doorways, get beaten with rods by adults. They may be alive, but their voices are silenced.
The ghost children are historical, they have a nearly silent history. Have you seen the children of the eastern jungles of Bolivia before the rubber merchants enslaved them? Have you heard the little Chinese girls who were sold by their fathers to brothels when the city of Singapore was decreed by the British to become their central port, when the starving patriarchs, the "coolies" of south China filled the British port in search of work and a bowl of rice.
The hungry child, the child slave, can you hear them playing?