Measles has been diagnosed in a University of Minnesota student, prompting health officials to notify about 2,500 students who may have been exposed and to alert local doctors, clinics and hospitals to watch for other cases of the highly contagious disease.

Dr. Gary Christenson, chief medical officer at the university's Boynton Health Services, said the student, who returned from international travel, attended classes Jan. 20-23 on the East Bank and visited the university's Recreation and Wellness Center on Jan. 20 before being diagnosed. U officials said he is in "self-isolation off campus" and is recovering.

Because of privacy issues, Christenson declined to identify the student or say whether he had been vaccinated.

"We're not highly concerned about this situation," Christenson said. "But we want to make sure we take precautions in case there might be the possibility of picking up another case."

Students, faculty and staff who've been immunized are at low risk of getting infected, university officials said. Christenson pointed out that students are required to be vaccinated when they enroll. The vaccine works for most people, but "it doesn't work 100 percent," he said.

The Minnesota Health Department, which is assisting the U, said Fairview Hospital officials also will notify staffers there who may have come in contact with the 20-year-old student when he sought treatment there.

"Measles is an extremely contagious disease, and potentially very serious for those who haven't been vaccinated," said Dr. Ed Ehlinger, Minnesota commissioner of health. "We are going to be watching this situation very closely."

Ehlinger said the potential risk to the general public is very low but he urged parents to vaccinate their children against measles, which is caused by a virus.

Symptoms include rash, accompanied by fever and in some cases cough or runny nose. Symptoms appear about eight to 12 days after a person is exposed to measles. The first symptom is usually fever. The rash usually appears two to three days after the fever begins and lasts five to six days.

According to preliminary data, Minnesota had two cases of measles in 2014, which were unrelated to each other. The university student is the state's first measles case in 2015.

Measles is rare in Minnesota because the state has high vaccination levels, said Doug Schultz, spokesman for the state Health Department.

A measles outbreak that began the week before Christmas has sickened at least 87 people in California, Arizona, Utah, Washington, Colorado, Oregon and Nebraska. Most of those infected had visited Disneyland and most had not been vaccinated.

One year before the introduction of the measles vaccine in 1962, there were 481,530 reported cases nationwide, according to the U.S. Centers for Disease Control and Prevention. In 2004, there were 37.

The Associated Press contributed to this report.

Mary Lynn Smith • 612-673-4788