Everything I've read suggests that this doctor is conscientious, selfless and kind. I don't believe he would have exposed others to Ebola if he had any inclination that he was infected. He measured his temperature twice a day as was required and didn't feel sick until today.

It could be the case that he was infected 2-3 weeks ago, but since the average time of symptoms showing up is 8-10 days because he was symptom-free before leaving for nyc, he might have thought he was fine.