that's a waste of time and would fall squarely in the category of "security theater".
The incubation period is so long that people with the virus can travel all over the planet from country to country before traveling to the US.
The 5 airport containment plan is a joke and is made to make everyone feel warm and fuzzy inside. Furthermore even with checks at every airport in the World, you would expect infected people to almost never be detected because the odds of symptoms during the short window of time that you're traveling are small (long incubation time once again).
The only way to contain this in Africa is to physically contain the carriers in Africa. Let the aide go in, let aide workers go in, shut down airports, border checkpoints, ports etc. This will NEVER happen because African natural resources are worth billions (trillions?) to western business interests (especially the tech industry). This is a tech forum, so I'm assuming people know this already.
As to the nurse getting sick, it's a tragedy and it is very sad that it has happened but hopefully something good can come out of this, a wake up call.