The virus escaped from the lab into the jungle and was picked up by a hiker. Only this time the hiker wasn't bitten by a monkey, but a mosquito. The hiker was just wealthy enough to get the attention of the press when she gave birth to a child suffering from Microcephaly.
Until then, local villagers who produced such offspring with regularity went unnoticed. The white volunteers took the burdensome infants from grateful mothers who were desperate to get back to work in the fields.
The Microcephalic children were raised and their organs harvested, none the wiser, until the virus spread out of control into wealthy population centers.
The End