May 7, 2001 -- If you don't want your happy memories of Ferris wheels, cotton candy, and livestock contests marred by a miserable bout of diarrhea and vomiting, be extra careful the next time you visit a county fair, warn CDC officials. When they delved into the source of E. Coli outbreaks at several of the festivals, they spotted some widespread and potentially deadly problems.
"We've demonstrated that attending a county fair is a risk factor for contracting an E. coli infection, even in the absence of a recognized outbreak," says researcher John Crump, MD, an epidemiologist with the CDC's division of food-borne and diarrheal diseases.
Crump's team was called in to investigate how more than 900 attendees of the 1999 fair in Washington County, N.Y., and more than 1,200 attendees of the 2000 fair in Medina County, Ohio, became sickened by the infamous 0157 strain of E. coli bacteria.
"Attending county fairs is a summertime ritual for millions of Americans," says Crump. "These fairs bring together concessions that prepare food and drink; children -- a group at risk of E. coli 0157 infection; and cattle -- a major reservoir of E. coli 0157. In addition, fairs often occur in the setting of temporary, unregulated water-distribution systems."
The team soon traced both outbreaks to defects in the fairground water systems. In one case, the same tap labeled 'unfit for drinking' was supplying water for both animal pens and for human food and drink preparation.
They wondered whether the situation was similar at other county fairs, even when no official outbreak is recognized or announced. So they stepped up CDC surveillance in 16 counties of northeast Ohio, four of which held fairs during late summer and early fall of 2000.
All patients identified with E. coli 0157 infection were asked about their fair attendance during the 10 days before becoming ill. Crump's team then compared the infection rate of county residents who had, with those who had not, attended a fair.
"Even though these fairs had not been identified as the source of recognized outbreaks," says Crump, "fair attendance was associated with increased risk of E. coli 0157 infection."