(RNN) - 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, held Feb. 23 to 25, telling them to watch for signs of the illness, the health department's spokesperson told the Dallas News.
So far, no one from Texas has developed the disease, but since it usually takes about 17 days for the symptoms to develop, it may only be a matter of time.
The National Cheerleaders Association said in a tweet that the championship was attended by 23,000 athletes and 2,600 coaches.
Mumps is easily spread through coughing and sneezing, and can even spread five days before symptoms appear, the Texas Department of Health said.
Symptoms of mumps include:
Though often mild, mumps can cause serious complications, including deafness and encephalitis, and can even be fatal.
The best strategy for preventing mumps is immunization. The Centers for Disease Control and Prevention suggests that children either get the two-dose MMR (measles, mumps and rubella) vaccine or the MMRV (measles, mumps, rubella and varicella).
The mumps used to be a common disease of childhood before the U.S. vaccination program began in 1967, which decreased outbreaks dramatically - by 99 percent.
Mumps outbreaks have been rare until recent years, jumping from 229 cases in 2012 to 6,366 in 2016, the CDC said.
Vaccinations help prevent outbreaks. When enough people get immunized for a disease like mumps, the disease can't travel as easily from person to person, lessening the chance of more people getting sick, the Department of Health and Human Services said. The concept is called herd immunity.
In recent years, vaccination rates have declined in some areas, as some people have opted not to vaccinate their children, worried about a link between vaccinations and autism.
The CDC said there is no link between autism and vaccinations.
But there is a link between a lower rate of immunization and vanishing herd immunity.
Experts warn if the vaccination rates drop below 90 or 95 percent, herd immunity could disappear, with substantial consequences for public health - and three-fold increase in measles cases and a $2.1 million increase in public health costs, a September 2017 report in JAMA Pediatrics said.
"What would happen if we stopped vaccinations? We could soon find ourselves battling epidemics of diseases we thought we had conquered decades ago," the CDC said.
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