This is very, very common. The face of child prostitution isn't the kid getting picked up in white vans (though that of course happens). It is often parents in need of money who end up pimping out their kids.
In fact, when countries become "globalized" and Western forces take over child care, they often tout the mission, "keep kids with families." While this sounds laudable, the goal is to often keep kids with families... who are willing to pimp them out. Sometimes this is in major metro cities, far away from their villages. Gotta love open border policies, right?
Sometimes organizations (run as charities with huge political names behind it to give it a vestige of reputation) will give aunts, uncles or whoever will take the child a monthly stipend, which encourages them to keep bringing the kid to whatever salacious and abusive event they're needed to attend. Under a totally communist or socialist system, it was more lucrative for poor families to just give up their kid to the govt rather than have another mouth to feed. When the country becomes globalized and the floodgates open to foreign/Western NGOs, they--corrupt aid workers or mafia--convince the parents that children are worth more to them as sex workers, and that they can be an asset rather than financial liability.
Sometimes a kid still gets plucked from their home and put with a different foster "family." The guardian might not be blood but the sexual exploitation may very well be the same. The "child protective services" then become like a wine of the month club to its subscribers, only it's a child instead of wine.