Los Angeles County health authorities say one of the most recent local cases of measles involved a person who visited popular tourism locations including The Grove shopping center, The Original Farmers Market and La Brea Tar Pits.
People who were at those locations and nearby areas on April 27 may be at risk of developing the highly contagious disease for up to 21 days.
Authorities say there is no current risk of exposure at those locations.
Health officials have been dealing with a small outbreak of measles as well as cases among travelers passing through.
So far, a large-scale outbreak has been avoided.
The Department of Public Health is urging people to be vaccinated against measles, especially if they are traveling internationally.