The National Cheerleaders Association, which has hosted cheerleading events since 1948, said on Twitter that it featured 23,655 athletes at its 2018 championship competition, in addition to 2,600 coaches from 39 different states and nine different countries.
A spokesman from the state health department told the Dallas Morning News that the person traveled from another state.
Symptoms include swelling on one or both sides of the face, tenderness of the salivary glands in the cheek and jaw area, slight fever, headache, general aches and muscle pain.
But even people with a mild case of the disease can spread it through saliva or mucus with coughs, sneezes, sharing food and more.
Those symptoms usually appear 16 to 18 days after the infection, and individuals can begin spreading the virus two days before showing symptoms.
Mumps is a contagious viral illness, according to the letter.
The mumps vaccine was created in 1967 and was mostly eradicated until a trend arose in Texas in 2016 with 191 cases reported, according to TDSHS.
"Many people do not have any symptoms", though they can still spread the virus, the Texas DSHS said. Anyone diagnosed with mumps or suspected of having the virus is advised to stay home for five days after swollen glands appear.