The Herald-Sun reports that as of Thursday, 43 people people had tested positive for the bacterial infection, including the three in Chatham County, two in Durham County and one in Person County. At least 27 victims had visited the State Fair in Raleigh Oct. 15 through 24. Officials believe most of the victims came into contact with fecal material from one or more sheep, goats or cattle at the fair.
From the article:

“Although the illness is often associated with eating undercooked ground beef, we suspect these cases may have been contracted through direct contact with live animals,” State Epidemiologist Jeffrey Engel said. “Outbreaks are often associated with fairs and petting farms, however we are still exploring every possible source.”
As the state continues to track down the source of the disease, Dr. Engel said that residents can help themselves by practicing prevention measures, especially in schools and child day care facilities.
“The best way to reduce the risk of getting E. coli, especially if a friend or family member is sick with the disease, is careful and diligent hand-washing,” he said. “Teachers and school officials will want to make sure they have plenty of soap and paper towels for their students. If teachers notice a student who appears to have any of the symptoms associated with E. coli, they should contact the parents as soon as possible.”

E. coli is associated with petting zoos because animals carry the bacteria in their intestines. People pick up E. coli by eating contaminated meat or through contact with manure, animals or contaminated surfaces. A number of the cases identified so far have been in contact with farm animals, however public health disease investigators have not yet determined the exact source or sources of the human cases.