The state health department is notifying 250 passengers who were aboard Saturday's Hawaiian Airlines Flight 15 from San Diego to Honolulu of a potential exposure to measles from a passenger.

A state laboratory confirmed that a 10-month-old who was on the flight has measles, health department spokeswoman Janice Okubo said.

The department on Monday began contacting those possibly exposed.

The health department already has given an immune serum globulin to a 5-month-old child who also was on the flight, to prevent measles infection, Okubo said.

"So far, four additional infants, potentially exposed on the flight, have been identified and will be administered preventive treatment by DOH," state epidemiologist Dr. Paul Effler said. "Hawaiian Airlines has been extremely supportive in this effort by providing passenger contacting information quickly."

According to San Diego County health officials, the 10-month-old child is the fifth confirmed case of measles in that county this year.

The child is believed to have been exposed at the Children's Clinic in La Jolla, Calif., where the first measles patient received care Jan. 25.

Hawai'i's health department is advising the flight's passengers to consult their doctor regarding their susceptibility to measles.

Measles is a highly contagious viral infection characterized by fever, cough, runny nose, conjunctivitis (red eyes) and a rash.

Patients are contagious from one to two days before the onset of symptoms to four days after appearance of the rash.