Health Officials Struggling to Pinpoint E. Coli's Spread
Byline: TIM CHRISTIE The Register-Guard
The county fair is a classic slice of wholesome Americana, where country folk show off their livestock and city folk see where their food comes from.
But now these fairs have become a hot spot for an emerging public health threat in the form of E. coli O157:H7, a virulent bacteria that live in the waste of farm animals and sicken humans who ingest the germs.
Nationally, at least six county fairs, as well as two dairy farms where visitors had contact with animals, have had E. coli outbreaks of varying degrees since 1998, including three in the past year, according to a Register-Guard survey of public health reports and news accounts.
"We suspect there are more out there," said Dr. Robert Tauxe, chief of the foodborne and diarrheal diseases branch at the Centers for Disease Control and Prevention in Atlanta.
The eight fair and dairy farm outbreaks have resulted in 309 confirmed and 1,286 reported E. coli infections; 34 people treated for hemolytic uremic syndrome; and two deaths. One 4-year-old Pennsylvania girl who visited a petting zoo required a kidney transplant because of the damage wreaked by the bacteria.
"Everyone in public health knows it's a major problem," said Mansour Samadpour, an environmental health professor at the University of Washington School of Public Health.
The Lane County Fair is the latest fair to be hit with an E. coli outbreak. Public health officials are investigating 59 reported cases, 50 confirmed by lab testing, at last month's event. The bug has hospitalized at least eight children with hemolytic uremic syndrome, or HUS, a potentially fatal complication of E. coli infection.
Investigators, after interviewing more than 200 sick and well fairgoers, have traced the source of the outbreak to the sheep and goat exposition hall. Exactly how the bug was spread in the hall hasn't been determined.
The fair outbreaks represent just a fraction of the toll E. coli O157:H7 takes on American health. The bacteria sicken about 73,000 and kills 60 people each year in the United States, and the vast majority of illnesses are classified as sporadic, or isolated cases.
E. coli in the air
Public health investigators have traced most E. coli outbreaks at fairs, dairy farms and petting zoos to two factors: contamination of water supplies by cattle waste and direct human contact with animals.
Fairs provide some unique circumstances that can create a perfect setting for spread of the disease.
CDC investigator Dr. Jay Varma, in a report on an E. coli outbreak at an Ohio county fair, described it this way: "Fairs represent particularly intense episodes of close contact between large numbers of humans, farm animals, and food/beverage vendors in the presence of unregulated water systems."
Contact with animal fur, railings or floors contaminated by E. coli-ridden manure is one obvious way of transmitting the disease. But at one Ohio fair, Varma and public health investigators suspect that E. coli bacteria was literally in the air.
When E. coli sickened 23 people at last summer's Lorain County Fair, CDC investigators traced the outbreak to a show barn called the Cow Palace, said James Boddy, director of environmental health at the county General Health District in Elyria, Ohio, about 50 miles southwest of Cleveland.
Animals were exhibited in the barn throughout the fair, and on the last night a teen dance was held, "with a lot of dancing and stomping" that kicked up plenty of dust, he said.
Investigators swabbed the barn and found E. coli in the rafters, on the bleachers, on the walls and in sawdust on the floor. Investigators suspect, but didn't prove, that the E. coli bacteria became airborne in the dust, then landed in food and drink and got swallowed by fairgoers in the barn, he said. …