Officials said the person is from out of state and was at Union Station sometime after 8 p.m. Thursday, August 27 into Friday, August 28.
The traveler arrived from Missouri at about 10:30 p.m. on Thursday and left the Amtrak Union Station at about 9:30 p.m. on Friday for Rochester, New York, according to officials.
"Amtrak has taken all proper steps upon being given the information by the authorities," a spokesperson said.
The Missouri Department of Health and Senior Services said the person boarded the Chicago-bound train (Train 318) at the station in Sedalia.
Health leaders say people, who may have been exposed to measles, need to look out for symptoms, such as a rash, high fever and watery eyes.
This comes after two cases were confirmed in Kane County.
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