Because of the recent Ebola outbreak in the area they come from and the weakened condition they'd be in traveling up from CA, I would think that quarantining them for the incubation period would be in order before sending them on their way anywhere. I recall the way a doctor was extremely isolated when he was suspected of having Ebola and was brought back to the States.
It is extremely doubtful that anyone in this group..and even more so because it was a group would have the means of getting here from Africa on their own. A charitable organization would most like have had them come through border control claiming asylum.. not try to sneak across.
Who..and what the motive is anyone's guess. It could even be indenture to a cartel where if they got away with it might literally be slaves until their debt was paid.