Officials from the Centers for Disease Control and Prevention (CDC) are saying that the measles outbreak linked to Disneyland originated from a foreign country, NBC reported.
Currently, health officials are still identifying which countries have been hit by the disease.
The outbreak, which began late last year, has been linked to visitors of California's famous theme park. But according to Dr. Anna Schuchat of the CDC, one of the visitors may have contracted the disease while outside the United States, and infected other park goers.
"We don't know exactly how this outbreak started but we do think it was likely a person infected with measles overseas," the medical officer said during a press briefing. "We assume that someone got infected with measles overseas, visited Disneyland park, and spread the disease to others."
Philippines was previously considered as the likely source of the disease since the country is experiencing an outbreak of its own. However, CDC officials ruled it out because they did not find evidence linking the U.S. measles outbreak to the Asian country.
Laboratory tests on the current virus revealed that its strains are similar to the ones that affected Dubai, Qatar, Indonesia and Azerbaijan.
As the agency continues to identify the origin of the virus, officials strongly maintain that vaccination is the key in preventing the disease from spreading to other states, according to Reuters.
"This is a wake-up call to make sure we keep measles from getting a foothold in our country," Schuchat said.
"This is not a problem of the measles vaccine not working," she added. "It's a problem of the measles vaccine not being used."
The doctor then urged medical facilities to conduct necessary procedures especially for patients who are showing symptoms of the disease.
According to Schuchat, doctors should assume patients have been infected with measles if they have rashes and a high fever. This is to ensure that those who could be carrying the disease receive proper treatment to prevent the virus from spreading to other people.
