A daycare center at a Southern California high school has been closed and more than a dozen infants placed under three-week quarantine after a baby enrolled in the program was diagnosed with measles, a school district official said on Monday.

The move comes as public health officials reported that more than 100 people across the United States were infected with measles, many of them traced to an outbreak that began at the Disneyland theme park in Anaheim in December.

The child, who is under a year old and therefore unvaccinated, was enrolled in the daycare center at Santa Monica High School, said Gail Pinsker, spokeswoman for the Santa Monica-Malibu Unified School District.

A freshman baseball coach at Santa Monica High School was diagnosed with measles last month, but Pinsker said the two cases were not connected and that the coach had recovered from his illness.

"There is concern in the community over this. This is a concerning disease," she said. "Over the last couple weeks we've encouraged families to get students immunized."

Pinsker said that the "infant room" at the daycare center had been closed indefinitely following the diagnosis and that 14 other babies enrolled there had been placed under 21-day quarantine on the orders of Los Angeles County health officials.

The daycare center's "toddler room" had been closed through Thursday, she said, and all children would be required to show proof of immunization before they would be allowed to return.

"The district is trying to stay on top this and being as transparent as possible," Pinsker said. "The health and safety of our students and staff is our first priority."

The California Department of Public Health said on Monday that 92 cases of measles had been confirmed in the state, up from 91 on Friday. More than a dozen other cases have been confirmed in 13 other U.S. states and in Mexico. No deaths have been reported.

Measles was declared eliminated in the United States in 2000 after decades of intensive childhood vaccine efforts. But last year the nation had its highest number of measles cases in two decades.

Most people recover from measles within a few weeks, although it can be fatal in some cases.