California is battling a surge of measles cases clustered around the famous Disneyland theme park, despite the virus being all but eliminated in the United States, authorities said.
Fifty-nine cases have been recorded since the end of December, the California Department of Public Health reported, urging people to get themselves vaccinated -- in the face of a movement against the vaccinations over concerns about links to autism in children.
"Of the confirmed cases, 42 have been linked to Disneyland or Disney California Adventure Park in Anaheim, California," the health department said. Five of the cases involved Disney employees.
"Initial exposures occurred in December, but additional confirmed cases visited Disney parks while infectious in January," the department added on its website.
Measles is highly contagious and can be spread through the air without physical contact. Infection usually begins with a fever followed by a cough, runny nose, conjunctivitis and a rash.
The health department said the spate of cases underscored the need for vaccinations against the illness. Twenty-eight cases from 34 for which data was available involved individuals who had not been vaccinated.
Measles has been officially eradicated from the United States since 2000 while remaining widespread in other regions including Europe, Africa and Asia.
Eradication means the disease is no longer native to the United States.
But there were 644 measles cases in the US last year, an enormous jump from 173 cases in 2013.
An analysis by the Los Angeles Times last year found that 9.5 percent of kindergarten children in an Orange County school district were exempted from vaccinations because of personal beliefs.
In a Santa Monica and Malibu school district, the rate was 14.8 percent, while statewide it was 3.1 percent.
Authorities said the best protection for children remained the MMR (measles, mumps, rubella) vaccine.
But an anti-vaccination trend in recent years has emerged, particularly in North America, amid fears the MMR vaccine causes autism, despite an array of studies which have contradicted those concerns.
"The clear consensus in the scientific community is that there is no association between vaccination and autism," the California health department said.