Hey, Michael, remember the UN clown who knew he had ebola

and got on an airplane anyway?  You said 'if ebola gets here, this is how it'll happen'; yep.
He came into direct contact with a friend who had Ebola. He rode with her in a taxi and carried her from the taxi to a hospital on September 15, four days before he flew to the United States. She was turned away from the hospital because the Ebola ward was full.

She died of Ebola early the following morning. Her brother also got sick and shows Ebola symptoms. That was at the same time that Duncan started getting sick. He left Liberia and arrived in Texas on September 20. Six days later he sought treatment at Texas Presbyterian Hospital, and was sent home. He returned two days later, and has been confirmed to be infected with Ebola.

Duncan also abruptly quit his job on September 4, so he might have already planned the trip to see his family in the U.S.

But he certainly knew that he had been exposed to Ebola by the time he boarded that plane and came to Texas, four days after his friend died of it. He must surely have known it when he first visited the Texas Presbyterian Hospital, and he must have known it when the doctors sent him home.

Editorial note: it has NOT been established that he was feeling sick prior to getting on the plane, despite the above blockquote.

Let that sink in, though: he knew he'd been exposed, and it's not unfair to deduce that he thought to himself, "the Americans will save me".
Yeah, if you CARRY YOUR SICK FRIEND, you know you've been exposed.  Get on the airplane anyway(possibly knowing you could spread it), because getting yourself here is FAR more important than a bunch of other peoples lives.  Wonderful bastard, aren't you?