Now, Northern Californians have something new to worry about when they ride the BART public transportation system: the measles. After discovering that a UC Berkeley student traveled on the BART for several days with the illness, health officials warn that other commuters could be at risk for the measles. “Measles is a serious, highly contagious disease,” said Dr. Janet Berreman, health officer for the City of Berkeley. “It spreads through the air, when an infected person coughs or sneezes.” Most people are vaccinated for the measles as children, as it can be especially damaging for this age group, but this student, apparently, was not.