If we get even a couple of more cases in the U.S. stemming from this outbreak, I could see it becoming increasingly difficult to keep all these folks quarantined. The average incubation period is 2-21 days, and three weeks is a long quarantine period.
This Forbes article discusses a researcher's study that suggests that 21 days might not even be long enough:
http://www.forbes.com/sites/jonforte...-to-new-study/