Public health investigators in North Carolina determined that the source of the majority of E. coli cases during the state's fair, October 15 to 24, was the Crossroads Farm Petting Zoo. Thirty three of the cases had E. coli O157:H7 that shared the same genetic fingerprint. Those fingerprints matched E.coli that was found in the Crossroads Petting Zoo environment. The outbreak genetic strain was not identified in environmental specimens collected from other State Fair ground locations. Direct contact with manure was most likely to cause infection.