So they keep importing potential Ebola carriers in daily. Because Racism.
After all, even though cutting off all flights and blocking all entrants originating in the affected three countries would stop 100% of the Duncans from getting here, we can't risk harming the economies of the 151st, 208th, and 223rd most productive countries in the world (Guinea, Sierra Leone, and Liberia, respectively. In case you were wondering, the scale only goes down to 228. That would be DRCongo, the other current African Ebola outbreak country.)
And seriously, it's not a like a few Ebola cases here and there are any big deal.
Because after all, what's the risk?
We've got this!
So when Ebola victim #2 arrives, and gives it away to someone else, what's the first thing they're going to ask the patient when they get to the hospital? (airport, anything else, fill in the blank...)
"Have you been to West African countries like Guinea, Sierra Leone, Liberia, or the Congo?"
And our hero, Billy Bob, or Apu from the QwikEMart, will honestly answer "No."
And then, wham-bam, be handed a prescription for something, anything, and sent home, for his complaints of headache, fever, muscle aches, and nausea. Just like a million cold and flu patients in the next six months.
And then, a few days later, when he comes back coughing up a lung or crapping kidneys,
Doctor Obvious will realize that you have Ebola! Which will be unfortunately too late to keep you from having already exposed your family, coworkers, all the healthcare workers there, the other people in the waiting room, the paramedics, the other kids at your kids school, the teachers too, and their combined families, along with the butcher, the baker, the candlestick maker, and every store clerk you saw when you went out to get aspirin, Ben Gay, and a tourniquet to keep from bleeding out your back end.
Because if you have no recent travel to Ebolaville, the Magic 8-Ball sez "You can't have Ebola!".
Even if you do.
Recall, please, that a lack of knowledge of Duncan's journey is apparently exactly why they missed his diagnosis. What chance will they have with someone who hasn't been to Africa?
So instead of screwing up the next Thomas Duncan, they'll screw up the next one hundred Thomas Duncans, who helpfully infect someone else, and those someones won't be the droids the nurses and doctors at the hospital are looking for either.
Like the UK guy and friend in Macedonia they're puzzling over now.
Or Officer Safety (apparently not infected) in Dallas. Because not everyone is going to have such a handy neon-light arrow pointing at the person who might've infected them.
Yet they'll still be infected, still seek treatment, still be contagious, but everyone in healthcare will miss them early, because they've been TOLD to.
By the Smart People. The Geniuses In Charge Of Knowing.
We have CYA protocols to cover us, so no one has to think anymore.
If the Ebola Decision Protocol says juggle lit flares in a pool of gasoline, that's what will be done.
Until a few hundred explosions, and people running around aflame make the news, and The Geniuses In Charge Of Knowing will slap their foreheads, say "Aha!" and put out new no-thinking-required protocols, and we'll go right back to what failed us the first time, will fail us the next time, and will fail us over and over again until the protocol is to tell people to THINK.
I'd tell you when that'll be, but my telescope doesn't go up to that high a magnification, and from personal experience, a lot of people doing the job are underequipped for that task.