State health officials are warning passengers who rode Amtrak's Northeast Regional train #171 on Aug. 17 that they may have been exposed to a person with measles.
The passenger boarded the train in Philadelphia and went onto Aberdeen, Baltimore, BWI Airport and new Carrollton, ending in Lynchburg, Va., at 8:36 p.m.
Passengers should look for signs of the viral infection, which is spread through coughing, sneezing and contact with secretions from the nose and mouth of an infected person. The first stage brings fever, runny nose, watery red eyes and a cough. Then, on the third to seventh day, a rash will appear on the face and spread.
If you were exposed and show symptoms, call your doctor for instructions. Measles is contagious.
There have been no cases among Maryland residents since 2009, though a non-Maryland residents who had traveled to the state was diagnosed in June 2011.
For more information, go to the state Department of Health and Mental Hygiene's website.