Largest epidemic of mumps in 20 years hits Iowa and spreads to surrounding states. More than 1,000 cases have been reported, and about half the 800+ cases in Iowa have been college students with childhood vaccinations. (Adults run greater risks from the infection.) The United States normally experiences 250 to 300 mumps cases in a year. An outbreak last year in the United Kingdom resulted in 56,000 cases. Canucks issue travel warning. Freepers are already making the mumps-immigrants connection.