BERKELEY, Calif. >> Berkeley health officials have issued a warning after a UC Berkeley student tested positive for measles after riding public transportation away from the school.

The San Francisco Chronicle reports the student was put in isolation Saturday. City spokesman Matthai Chakko says the student rode the AC Transit 25-A bus on the afternoon of Aug. 24.

Measles is a highly infectious, airborne virus. Those infected can carry the virus for up to three weeks before developing symptoms, which include high fever, cough and watery, red eyes. A rash usually develops days after the fever.

Dr. Janet Berreman, Berkeley’s health officer, has encouraged the Berkeley community to make sure they have received the measles vaccine.

City officials encourage those who develop symptoms to contact their health care provider immediately.