South Africa is pretty health conscious. I recently did a safari in Zambia and had to route my travel through Amsterdam instead of S.A. because I didn't do a Yellow Fever vaccine (it's contra-indicated for those of us 60 or older... too risky) and S.A. won't let you go through their country without it (if you're coming from other African countries).
So, I'm not surprised at all that they want to prevent Ebola sufferers from wandering around in their airports and country.
Just personal opinion here, but it seems that former brit colonies are somewhat better with this stuff. Sierra Leone notwithstanding.
YMMV.
We’ll see what I think in a couple months based on whether or not Nigeria really has this under control. And I hope they do. They have a lot to lose if foreign investments and building projects end. If you want to see some of what they’re up to do a search for ‘Eko Atlantic’.