It's a nightmare scenario for public health officials: a traveler infected with a highly contagious virus passes through an airport while asymptomatic, unknowingly transmitting the disease to others and sparking a widespread outbreak.

A Maryland resident who passed through Terminal A at the Washington, D.C., area airport last week tested positive for the highly contagious virus.

There was a confirmed measles case at Dulles Airport last Wednesday, Virginia health officials announced over the weekend. Why it matters: If you were in Terminal A, headed to the main terminal or in the baggage claim area between 4-9pm on March 5,