The disease, rare in the United States but highly contagious and potentially serious, has now infected at least eight people in Orange County and more than a dozen statewide.
It causes fever, rash, coughing and red, watery eyes. Those infected are contagious from about four days before the rash appears through four days after.
In the original six cases, three were unvaccinated children -- all old enough to be vaccinated -- who contracted measles at Disneyland, said Orange County Health Care Agency spokeswoman Nicole Stanfield.
Three others are adults; one was unvaccinated, one was partially vaccinated and one was fully vaccinated. None of the adults was hospitalized, Stanfield said.