Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Thousands of cheerleaders may have been exposed to mumps last month at a national competition in Dallas, Texas health officials said Wednesday.

They've sent letters to attendees of the National Cheerleaders Association All-Star National Championship informing them that someone who took part came down with the virus. They are not identifying the patient.

23,655 athletes

2,600 coaches

1320 teams

39 states

9 countries

1 competition



NCA All-Star Nationals 2018 #theworkisworthithttps://t.co/FfCLWtfKUP — NCA Updates (@NCAupdates) February 28, 2018

More than 23,000 athletes and 2,600 coaches participated in the competition from Feb. 23 to 25 at the Kay Bailey Hutchison Convention Center in Dallas, according the the organization's website. Many traveled from out-of-state.

Mumps, which is spread through the saliva or mucus of an infected person, causes puffy cheeks and a swollen jaw as it affects the salivary glands. It can cause fever, headache, loss of appetite, and fatigue. In some rare cases it can also cause deafness or encephalitis, swelling of the brain. Some people don't show any sign of infection.

Risk is very low

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Studies have shown that vaccinating people during a mumps outbreak can help control it. There is no treatment for mumps once someone gets it, but most people recover completely in a few weeks.

“For the vast majority of people, the risk is very, very low,” said Chris Van Deusen, a spokesman for the Texas Department of State Health Services, while also noting that there have been no reports of people developing symptoms in connection with the case.

“Just to be on the safe side we want people to be on the lookout for symptoms. We want folks to be aware of it and looking out for those telltale mumps symptoms.”

The next few days will be very telling.

“The incubation period for mumps can last from two weeks to a month, so the cheerleaders in Dallas should watch for symptoms of fever, muscle aches and swollen glands,” said NBC News correspondent Dr. John Torres. “Because the virus is spread via our saliva it’s important not to share utensils or cups with anyone suspected of having the mumps.”

“For the vast majority of people, the risk is very, very low.”

Cheerleaders from the competition who have received two doses of the mumps vaccine are encouraged to contact their doctors to get an additional booster dose of the MMR vaccine to increasing waning immunity.

“If you, your child, or any other individuals linked to this event experience or have experienced mumps symptoms, please contact your healthcare provider and inform them of your exposure to mumps,” Antonio Aragon, a state health official, wrote in the letter.

Mumps has been on the rise with unrelated outbreaks around North Texas and Hawaii in the past few months, which officials said was the worst seen in years but is beginning to subside.

Most people who are vaccinated with the measles-mumps-rubella (MMR) vaccine are protected against the virus — one dose is 78 percent effective and two doses is 88 percent effective.

Because efficacy can wane over time, there are frequent outbreaks of mumps in the U.S.

So far this year, there have been 130 reported cases from January 1 to January 27 across 25 states and in 2017, more than 5,600 people got mumps, according to the Centers for Disease Control and Prevention. In 2016, 6,366 cases were reported — the worst year for mumps in the U.S. since the MMR vaccine program was introduced in 1977.