The woman flew in from the Netherlands on Northwest Flight 33, arriving at 3:25 p.m. She departed for Portland on Horizon Airlines Flight 2243 at 5 p.m.

Health officials said they are not aware of anyone who caught the measles from the woman but warned that people on her flights, in the S and C concourses or at Gate 2J in the C Concourse between 3:25 and 7 p.m. that day might have been exposed.

The Health Department also alerted a handful of passengers who sat next to or near the woman, and is looking for others, spokesman Matias Valenzuela said.

One passenger on the plane from Amsterdam was from Pierce County, said Joby Winans, spokeswoman for the Tacoma-Pierce County Health Department. No other information on that person was available.

Health officials urged people who might have come into contact with the woman to be alert for the symptoms of the measles and to get to a doctor immediately if they appear.

A measles rash appeared on the woman March 28. She left Portland for Amsterdam the next day on Northwest Airlines Flight 92. Her measles diagnosis was confirmed by a blood test in the Netherlands on April 4.

The woman is in her 20s, and was not vaccinated against the illness.

Most persons born before 1957 had the disease in childhood, and younger persons are routinely vaccinated against measles. All those people have immunity against the disease, according to the Health Department.

Before a vaccine was developed, measles was a common infection, with infants and adults more likely than children to suffer serious complications.

It’s rare now, though. State health officials receive one to 38 reports of measles infections a year. The last measles-associated death in Washington was in 1990.

Measles is caused by a virus, which can spread in droplets and secretions from the nose and throat of an infected person. The virus can contaminate objects others may touch.

The virus also can be spread by breathing the air where an infected person has been for up to two hours after the person was present.

M. Alexander Otto: 253-597-8616

What happens with measles

Symptons: Measles symptoms begin seven to 21 days after exposure, starting with a runny nose, watery red eyes, cough, and high fever.

In the first few days, tiny white spots appear in the mouth.

After two to four days, a raised red rash starts on the face and spreads down the body and out to the arms and legs. The rash usually lasts four to seven days.

Effects: Untreated, measles can lead to ear infections, diarrhea, pneumonia and inflammation of the brain. That can lead to convulsions, deafness or mental retardation. It rarely causes death.

Measles also can cause miscarriages or premature delivery in pregnant women.

M. Alexander Otto, The News Tribune