E. coli test results show no clear source of deadly county fair outbreak

Pigs wait for auction during the Junior Livestock Auction at the San Diego County Fair.
(Nelvin C. Cepeda)

Environmental and animal testing has failed to reveal a clear source of the deadly E. coli outbreak among San Diego County Fair visitors.

In an update published Wednesday afternoon, July 31, the county health department said that none of the 32 environmental samples, nor any petting zoo, pony ride or cattle testing, has come back positive for O157:H7-type E. coli bacteria. That was the kind detected in the 11 confirmed outbreak cases, including 2-year-old Jedidiah Cabezuela, who died of severe complications after visiting animal areas of the Del Mar Fairgrounds on June 15.

All 11 cases reported having animal contact during fair visits, and administration, acting on the advice of local public health officials, closed all such exhibits to the public on June 29.

Dr. Eric McDonald, medical director for the county’s epidemiology and immunization services branch, said Wednesday evening, July 31, that the common thread among all 11 cases means that the original hypothesis about the outbreak’s origins remains unchanged.

“Even though we have not found a specific animal that we can say the outbreak came from, we know that the cases all were people who went to the fair and had animal exposures in the livestock barn area ,” McDonald said. “It is likely that an animal or an environmental exposure in the livestock barn is where they were exposed.”

While all petting zoo and pony ride animals were tested, only two cattle from the livestock barn were similarly checked out. The majority of the animals present left the fairgrounds before samples were collected.

In an email sent Wednesday evening, July 31, Annie Pierce, a spokeswoman for the 22nd District Agricultural Association that runs the fairgrounds, said that competitive livestock rotates through the fairgrounds on a weekly basis.

“The animals return home each Sunday night, and a new batch arrives each Tuesday,” Pierce said. “When we learned of the dates the children had visited the Fair, those specific competitive livestock animals had already been released. That’s why these animals were not sampled and tested, as they were no longer on site.”

Pierce added that fair administration followed all directives from the county and from the California Department of Food and Agriculture where testing was concerned. On June 29, she said, food and agriculture workers took soil samples and swabbed walls and pens of all livestock enclosures, including those inside the fair’s “California Grown” exhibit, which housed educational animal displays.

Test results arrived just as the fair board has received claims for damages from several families with loved ones sickened during the outbreak. Though no lawsuits have yet been filed, the claims find fault with how animal areas were operated from the methods used to warn visitors of potential E. coli exposure to the placement of hand-washing stations outside the barns where animal exhibits were staged.

— Paul Sisson is a reporter for The San Diego Union-Tribune