PHILADELPHIA (CBS) – Officials with the Philadelphia Department of Public Health say they believe they have identified the person responsible for the recent mumps outbreak at Temple University. Officials say they believe the person may have contracted mumps while traveling abroad.

“We can confirm that who we think the first case was an international traveler,” said James Garrow, of the Philadelphia Health Department.

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Mumps Cases Spreading Throughout Philadelphia Region Following Temple University Outbreak 

Garrow would not specify if the person was a student or employee at Temple or which country they traveled to, as they believe it may be used to identify the person.

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Since the outbreak first started in February, officials have had a tough time containing it. In an effort to prevent further cases, Temple held two free walk-in vaccination clinics on campus last week for students, staff and faculty. Officials say more than 4,000 people received the booster shot. Over 100 people associated with Temple contracted the mumps.

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Mumps cases have also been reported at Drexel University, West Chester University, Abington Senior High School and North Wales Elementary School.

Mumps is a viral disease characterized by fever, swelling and tenderness of one or more salivary glands. Mumps is transmitted by saliva droplets or by direct contact with the saliva of an infected person. People with mumps are considered infectious from two days before swelling begins, through five days after the start of swelling.

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You can learn more about mumps on the Centers for Disease Control and Prevention website.