The number of E. coli cases under investigation rose to 27 Tuesday, with 18 confirmed, and North Carolina health officials opened a command center in downtown Raleigh to coordinate information as they work to trace the source of the bacterial outbreak.
The strongest lead so far is a petting zoo at the N.C. State Fair, but health officials were exploring other possibilities.
Of the 27 cases under investigation, 14 have links to the State Fair, one attended the Cleveland County fair, six have not completed questionnaires with that information, and six did not attend the October fair in Raleigh.
"We're not certain where it came from," said Bill Furney, a spokesman for the state Division of Public Health. "We're looking at all possibilities."
E. coli is a bacterium that lives in the guts of ruminant animals such as cattle, goats and sheep and does them no harm. The animals shed the bacteria in their feces. The bacterium is most often transmitted to people when feces contaminate food. But it can also be passed on farms or at petting zoos.
Health investigators in Birmingham, Ala., currently are probing an outbreak there that might also be linked to a large agricultural fair; so far, seven children are estimated to have been infected.
"It's not uncommon for it to spread at fairs," Furney said. For that reason, he said, State Fair organizers have hand-washing stations posted near livestock exhibits and petting zoos.
Furney said the North Carolina cases still appear to be animal-to-human infections, hitting mostly children. So far, he said, no secondary, human-to-human infections have occurred. Some of the children attended school, however, and state health officials are working to make sure that the bacteria don't spread from that contact.
Spread of the bug can be stopped with good hygiene -- in particular, frequent hand-washing. Furney declined to disclose where the children had attended school.
There is no treatment for E. coli infection, which causes nausea, vomiting and severe diarrhea. It can lead to permanent kidney damage.
POSSIBLE CASES IN OUTBREAK
E. coli cases are being investigated in the following counties, with confirmation provided by the state laboratory:
MECKLENBURG: Four cases, all confirmed
WILSON: One case, confirmed
LEE: Two cases, one confirmed
HARNETT: One case, not confirmed
WAKE: Six cases, five confirmed
CLEVELAND: One case, confirmed
UNION: Two cases, both confirmed
CHATHAM: Three cases, one confirmed
DURHAM: One case, confirmed
FORSYTH: One case, confirmed
MOORE: One case, not confirmed
CUMBERLAND: One case, not confirmed
NASH: One case, confirmed
CASWELL: One case, not confirmed
JOHNSTON COUNTY: One case, not confirmed
(N.C. DEPARTMENT OF HEALTH AND HUMAN SERVICES, PUBLIC HEALTH DIVISION)