Four confirmed and as many as 10 E. coli cases have been reported in DuPage County, Illinois, according to a report in the Chicago Tribune. The Tribune reported that a Lombard restaurant was closed Friday after being identified as the potential source of the E. coli outbreak.  The restaurant, which was unnamed by public health officials, closed Friday afternoon at 5 p.m. Melaney Arnold, a spokeswoman for the Illinois Department of Public Health, told the Tribune that her agency was investigating other, related E. coli cases in the area.  She said lab testing was in progress.