Stock Shows and Petting Zoos Source of Many E. coli Outbreaks


Reports that a large and growing outbreak of highly toxic E. coli O157:H7 linked to Colorado’s largest stock show has led E. coli expert Bill Marler to again urge animal exhibitors to comply with existing safety guidelines.

“Unfortunately, we keep seeing outbreaks of E. coli O157:H7 at petting zoos and animal exhibits,” said Marler. “In the last 20 years there have more than two dozen outbreaks of E. coli traced to such events. As with this outbreak, the victims are primarily children.”

The ongoing problem led the CDC to publish recommendations for reducing the risk of transmitting E. coli and other human pathogens at animal exhibits. In the wake of devastating E. coli outbreaks, several states including Pennsylvania and North Carolina, have enacted laws requiring similar precautions. Yet in representing dozens of children sickened in these outbreaks over the years, Marler Clark has seen animal exhibitors continue to disregard the simple precautions.

“E. coli can cause devastating illnesses, especially in children,” continued Marler. “Simple precautions like educating fairgoers about the risk, proper hand-washing and modest limits on the nature of human animal contact can greatly reduce the risk of transmission. Hoping it won’t happen again is a much less effective strategy.”

Escherichia coli (E. coli) are members of a large group of bacterial germs that inhabit the intestinal tract of humans and other warm-blooded animals. Most strains—or serotypes—of E. coli do not cause disease in humans, but the toxic serotypes can cause serious illness and even death.

E. coli is often contracted by consuming food or beverage that has been contaminated by animal (especially cattle) manure. At animal exhibits, animal manure is in great supply. The E.coli bacterium is very hardy, so it can live for a long time on a surface like a fence or on the animal itself. If it gets on a child’s hand, no food vehicle is needed. A tiny amount can cause severe illness.

The first symptom of E. coli infection is the onset of abdominal pain and severe cramps, followed within 24 hours by bloody diarrhea. This is hemorrhagic colitis, and it typically occurs within 2 to 5 days of ingestion of E. coli; however the incubation period—the time between the ingestion of E. coli bacteria and the onset of illness—may be as broad as 1 to 10 days. Anyone with a family member experiencing these symptoms is urged to visit their health care practitioner and request a stool test.

BACKGROUND: Some previous outbreaks include Lane County, OR fair, North Carolina State Fair/Crossroad Farm Petting Zoo, and Florida State Fair/AgVenture Farms.