Assuming he followed proper procedure (which for all we know, he supposedly did), then why would you be suspicious of any African immigrant?
"God is the name by which I designate all things which cross my path violently and recklessly, all things which alter my plans and intentions, and change the course of my life, for better or for worse."
-C G Jung
If you were a medical professional would you want to treat an Ebola patient now?
I wonder what's wrong with Americans today that they can't see the importance of protecting American citizens from a plague. Maybe they're worried that by restricting travel from west Africa, we're moving in the direction of putting a limit on immigration, if that's the case then please put your own politics aside and understand that there comes a time when you have to protect yourself.
The US has treated patients prior to Duncan, and none of those healthcare workers contracted ebola. The matter needs to be researched. At what stage did the nurse treat him? Did she treat him before or after he was diagnosed and sent home?
Also note, the media is known for blowing stories like this out of proportion. A few months ago it was camel flu or something like that from mostly Arab nations, and before that, it was swine flu.