The Virginia Department of Health (VDH) is warning travelers who were in Dulles Airport on January 3 or Reagan National Airport on January 4 to stay alert for signs of measles if they never received a vaccine.

A traveler with a now-confirmed case of the highly contagious illness passed through the international arrivals area of Dulles between 4 and 8 p.m. on Wednesday, Jan. 3. The person then was in Terminal A at National between 2:30 and 6:30 p.m. on Thursday, Jan. 4.

The VDH is working to contact all passengers who were on the flights with the sick person.

The illness spreads easily through the air when a sick person breathes, coughs or sneezes. The symptoms include a fever of 101 degrees or higher, along with a runny nose, watery eyes and a cough that begins 7 to 14 days after exposure. After symptoms begin, a rash can appear on the face and spread to the rest of the body within 3 to 5 days.

The department asks anyone who has not had a measles or MMR vaccine to watch for symptoms until January 25. If people become sick, they should isolate and contact a doctor right away.

The VDH says most people in the state are vaccinated, as 95% of kindergartners have the vaccine. However, infants under 12 months are too young to receive a vaccine.

The department advises healthcare providers to be alert for reports of illness that could be measles. Doctors are reminded that measles is an “immediately reportable disease.”