All but three of the 26 patients being investigated for E. coli illnesses visited the North Carolina State Fair, state public health officials said today, adding that it is increasingly likely that something at the fair caused the illnesses. Of those cases, tests have confirmed that E. coli caused 10; the rest remain under investigation, Division of Public Health officials said in a statement released today. In addition to the 14 cases in Wake and six in Sampson County, single cases have been identified in Cleveland, Durham, Franklin, Johnston, Orange and Wilson counties. The 26 reported cases are split evenly between children and people older than 18. Five people are in the hospital for treatment, four children and one adult.