The theme park was the site of a major outbreak about five years ago.
A person who was infectious with measles visited Disneyland last week, leading public health officials to warn that hundreds of other people at the theme park were possibly exposed to the highly contagious disease.

Read more from Adeel Hassan / New York Times

A teenager with measles was infectious when she visited Disneyland, Universal Studios and other heavily visited sites in Southern California earlier this month, public health officials said.
The teen was on a trip from New Zealand and flew into Los Angeles International Airport. She visited Disneyland and California Adventure, among other attractions from Aug. 11 to Aug. 15. She also reportedly traveled to Universal Studios, Madame Tussauds and the Santa Monica Pier during the trip, the officials said.

Read more from Morgan Krakow / Washington Post

LA Public Health  Press Release : 
https://twitter.com/lapublichealth/status/1165027496862965760
 http://publichealth.lacounty.gov/phcommon/public/media/mediapubhpdetail.cfm?prid=2121