It's low risk right now, as of NBC News:
Schuchat says this first imported case poses only a low risk for the general public. "We don't have a sense right now that this is very easy to spread," Schuchat told reporters on a conference call.
The virus has not been known to spread on airplanes or buses. Most cases have been among people caring for sick patients or in very close contact with them.
The CDC says it is tracking down anyone who might have been in contact with the patient, including airplane seat mates, out of an abundance of caution. They're also checking health care workers who cared for him.
http://www.nbcnews.com/health/health...se-mers-n95871
