Texas health officials said tens of thousands of people from 39 states and nine countries that may have been exposed to mumps after an infected person attended the National Cheerleaders Association All-Star National Championship in Dallas.

Texas Department of State Health Services sent letters to everyone who attended the competition from February 23 to 25, telling them to watch for signs of the illness,

Get more details about the potential mumps exposure here and what symptoms to watch for if you’ve been exposed.