This may look humanitarian, but I don't think it is. Africa has resources we need in the future, along with we may be in need for help ourselves with man power in conflict or stratigic location. We do pretty good on the medical side of things, and the African goverment will pay us big for that. Risk vs. reward. We have the know how and means to contain and treat, they do not have that on a large scale. We show up wearing a cape; now we have a strong allie in land mass, resourses, and population. We will end up fighting in their civil war that has been going on for decades, and it may be a vietnam 2.0. In the mean time, I hope we don't have a large scale incedent on the home land.
The force is trying to be down sized. Keeping the troops out there and having us get $$$ by another government, even if it is resourse deals, could be benificial. The risk of exposing troops to a disease, leaders have talked it with confidance that we can protect our troops and it will be fine.
My .02