LOS ANGELES (KABC) -- Five more people have fallen ill with the measles, which brings the total number of cases to a dozen, health officials said.
Those five people visited Disney theme parks in December.
Six patients in Orange County have been diagnosed with the illness, and only one was fully vaccinated against the disease. All six patients also visited Disney theme parks in December.
Disney officials said they are working with public health authorities to provide any assistance.
Health officials urge anyone with measles symptoms to call their doctor before seeking medical attention as several people were exposed to the illness at two local hospitals and a lab.
The California Department of Public Health reported seven people in the state and two people in Utah likely contracted measles on trips to Disneyland or Disney California Adventure between Dec. 15 and Dec. 20. In Colorado, the El Paso County Public Health Department said one patient was diagnosed with measles at a local hospital after visiting a California theme park.
While measles had been eliminated in the U.S. since 2000, large measles outbreaks were reported in Western Europe, Pakistan, Vietnam and the Philippines in recent years, according to health officials.
Measles is a highly contagious virus that lives in an infected person's nose and throat mucus and spreads through coughing and sneezing, according to the Centers for Disease Control and Prevention.
Symptoms include a fever, cough, runny nose, red eyes and a red rash that usually appears on the face and spreads to the rest of the body.
The Orange County Health Agency released a list of potential exposure locations and times on their website.
The Associated Press contributed to this report.
The Walt Disney Company is the parent company of ABC7.
5 more cases of measles confirmed