SEATTLE -- A woman with measles had a stopover at Seattle-Tacoma International Airport last month while she was contagious, health officials said.

The woman in her 20s was traveling from the Netherlands when she stopped at Sea-Tac on March 26.

Health officials said people on Northwest Flight 33 and people who were in the S concourse, near Gate 2J or on the S concourse train between 3:25 p.m. and 7 p.m. should be alert for symptoms of measles. Anyone with symptoms should contact their doctor.

Health workers are contacting people who were seated near the woman during the Amsterdam-to-Seattle flight.

The passenger flew from Seattle to Portland on Horizon Airlines Flight 2243, departing from Seattle at 5 p.m.

On March 28, the woman developed a rash. She left Portland for Amsterdam on March 29 aboard Northwest Airlines Flight 92. In the Netherlands, blood tests confirmed a diagnosis of measles on April 4, health officials said.

Measles is a highly infectious and usually severe illness that causes fever, rash, cough, and red, watery eyes. The rash begins on the face and spreads to the rest of the body. A fever -- often greater than 101 degrees -- cough and other symptoms begin two to four days before the rash appears.