USDA's Food Safety and Inspection Service reported:
FSIS was notified of an investigation of E. coli O157:H7 illnesses by the Wisconsin Division of Public Health on Jan. 10, 2013. Working in conjunction with the Wisconsin Division of Public Health, three case-patients with the outbreak strain have been identified in the state with illness onset dates ranging from Dec. 29, 2012 to Jan. 1, 2013. Among the three case-patients with available information, all three reported consuming raw ground round; two consumed product ground and purchased on Dec. 24, 2012; the third consumed product ground and purchased on Dec. 30, 2012 prior to illness onset.
The colitis caused by Escherichia coli (E. coli) O157:H7 is characterized by severe abdominal cramps, diarrhea that typically turns bloody within 24 hours, and sometimes fever. [4]
The incubation period—that is, the time from exposure to the onset of symptoms—in outbreaks is usually reported as 3 to 4 days, but may be as short as 1 day or as long as 10 days. [4, 13, 26] Infection can occur in people of all ages but is most common in children. [26]
E. coli O157:H7 and other Shiga toxin-producing E. coli (STEC) infections can lead to a severe, life-threatening complication called the hemolytic uremic syndrome (HUS). [4, 13]
HUS accounts for the majority of the acute deaths and chronic injuries caused by the bacteria. [3] HUS occurs in 2-7% of victims, primarily children, with onset five to ten days after diarrhea begins. [23, 44] “E. coli serotype O157:H7 infection has been recognized as the most common cause of HUS in the United States, with 6% of patients developing HUS within 2 to 14 days of onset of diarrhea.” [44, 45] And it is the most common cause of renal failure in children. [26, 45, 48]