In the case of the 23 year-old Tejada, who comes from Panama, reporting to spring training means potentially not seeing his family again until October.

WSJ: On Time? You're Late

Some U.S. colleges began reporting cases last April, after students returned from spring break.

CNN: Swine flu goes to college

The U.S. Weather Bureau started reporting tornadoes, thunderstorms, hailstorms, lightning and high winds at a few experimental locations across the United States in spring 1943.

CNN: STORY HIGHLIGHTS