Disneyland has always been a place families go to escape the mundane. While Disney theme parks are notorious for long wait times and huge turkey legs, measles has never been part of the Disney experience until now.

Back in December, an outbreak of measles began at the Disneyland Park in Anaheim, Calif. Since then, 70 people have been diagnosed with measles, according to USAToday.com. The outbreak has spread to states like Utah, Colorado, Oregon, Arizona and Mexico.

According to the Centers for Disease Control, measles is a very contagious disease caused by a virus, and it stays in the air even after the infected person has left the area.

In 2000, the virus was actually declared “eradicated,” at least in the United States, but it seems like measles is back with a vengeance, the CDC reported. In 2014, 644 people were diagnosed with measles.

So why the sudden outbreak in measles?

In Disneyland, thousands of tourists from all around the world visit the theme park daily. Plus, whether someone’s waiting in line or counting down the minutes for the parade to start, there are always people around who may be sick.

Since measles is so contagious, it’s no wonder the disease could spread like wildfire in what is called, “The happiest place on earth.”

While vaccinations exist to protect oneself from measles, there are people who have never received the vaccination necessary to protect not only themselves, but also those around them.

According to USAToday.com, six of the cases at Disneyland were infants, and therefore too young to receive the vaccination.

While only time will tell when the measles outbreak will be contained, it’s safe to say that a trip to Disneyland might be on hold until the outbreak subsides.