Unvaccinated Traveler Sparks California Measles Warning

California health officials warned of measles exposure — measles is a highly contagious virus — in Alameda, Butte, Kern, Los Angeles, Sacramento and San Joaquin counties. An infected, unvaccinated passenger rode Amtrak trains and thruway buses, arriving Los Angeles 10 September, then visiting Bakersfield, Stockton, Oroville, Sacramento and Emeryville before leaving for Denver.