States in the American Midwest are working to contain an outbreak of the mumps virus.Health workers are vaccinating college students and others who live or work close together.

Mumps used to be common in the United States in babies, children and young adults.In nineteen sixty-seven, researchers developed a vaccine to prevent it.

Mumps is usually not serious.There is a risk, however, that it can lead to problems like infection of the brain and hearing loss.In women it can cause failed pregnancies; in men it can cause testicular damage.

Iowa is the state most affected by the outbreak.Since December, Iowa has reported more than one thousand cases of mumps, either confirmed or suspected.Health officials say young adults eighteen to twenty-five years old have had the highest number of cases in Iowa.

This is the largest mumps outbreak in America in years.The United States has had an average of fewer than three hundred cases yearly since two thousand one.

Mumps generally causes high body temperature, headaches, muscle pain and tiredness.It also causes painful swelling of salivary glands near the jaw line, especially below the ears.

People with mumps are sick generally for about a week or so.Many people get mild cases.Some infected people never even get sick.

The virus spreads easily.That can happen when infected people sneeze, cough, kiss or share food or drinks.People who touch surfaces with the virus on it can also get infected.Hand washing can help prevent the spread of mumps.

There is no treatment.Most American children receive a combined vaccine to prevent mumps and two other diseases: measles and rubella.

Experts at the Centers for Disease Control and Prevention say the outbreak might have begun at a college.And it might have started with a traveler.Britain has been dealing with a mumps outbreak that has resulted in more than sixty thousand cases.

C.D.C. officials note that the British cases have happened mostly in young adults who had only one injection of mumps vaccine or none at all.The experts say one vaccination should prevent about eight out of ten cases of mumps.Two should prevent about nine out of ten.

Young adults in the Midwest are being urged to find out if they had one or two vaccinations as children, or any at all.

This VOA Special English Health Report was written by Cynthia Kirk.Read and listen to our reports at WWW.51VOA.COM.I'm Steve Ember.