Escherichia coli O157:H7 causes 73,000 illnesses in the United States annually. We reviewed E. coil O157 outbreaks reported to Centers for Disease Control and Prevention (CDC) to better understand the epidemiology of E. coli O157. E. coil O157 outbreaks ([greater than or equal to]2 cases of E. coil O157 infection with a common epidemiologic exposure) reported to CDC from 1982 to 2002 were reviewed. In that period, 49 states reported 350 outbreaks, representing 8,598 cases, 1,493 ...