A report has been released in relation to an outbreak of Shiga toxin-producing E. coli (STEC) infections in Tennessee, with health authorities linking the cases to attendance at an animal exhibit. The outbreak, which occurred between September and October 2023, has raised concerns about the safety measures in place at such events.

The Tennessee Department of Health (TDH) Northeast Regional Office was first alerted to the outbreak on Oct. 3, 2023, following reports of two STEC cases. A total of nine patients were identified, with seven requiring hospitalization and four developing hemolytic uremic syndrome (HUS), a severe complication of STEC infections that can lead to kidney failure.

Of particular concern is the fact that eight out of the nine confirmed cases were children between the ages of 1 and 7 years old. All cases of HUS occurred in children aged 1 to 6 years old, highlighting the vulnerability of young attendees at such events.

The outbreak investigation, conducted in collaboration with local health departments, revealed that a significant number of cases were directly linked to attendance at the animal exhibit or were among household contacts of those who attended. Whole genome sequencing patterns further supported a common exposure to STEC O157:H7 among the affected individuals.

about the animal exhibit
The animal exhibit featured various species including cattle, sheep, goats, pigs, rabbits, a pony and poultry. Approximately 2,300 elementary school students primarily from kindergarten and second grade attended the event, wher they were allowed to touch animals. Food, including pizza and milk, was served separately from the animal exhibit.

Despite the presence of temporary handwashing stations and hand sanitizer, the extent to which hand hygiene was supervised remains unclear. An analysis of reported handwashing and animal contact revealed that while handwashing appeared to decrease the risk of infection, direct animal contact increased it.

Health department officials undertook epidemiologic, environmental and laboratory investigations to identify the source of the STEC exposure. Recommendations were subsequently issued to enhance safety measures at similar events, including improved hand hygiene practices, better integration of handwashing facilities, and education about the risks associated with animal contact.

In response to the outbreak, TDH collaborated with local authorities to disseminate information to parents, healthcare providers, and event organizers. Preventive measures and recommendations were shared to mitigate the risk of future outbreaks associated with animal exhibits.

Past outbreaks
This outbreak of Shiga Toxin-Producing E. coli (STEC) serves as a grim reminder of the potential health risks associated with interacting closely with farm animals. Recent petting zoo incidents at Lucky Ladd Farms in Tennessee, Georges Mill Farm in Virginia, and the San Diego County Fair in California and others have highlighted the dangers posed by direct contact with animals harboring E. coli bacteria. Despite efforts by health departments and fair organizers to implement control measures and promote hygiene practices, such as handwashing after animal contact, these outbreaks continue to result in serious illnesses and, tragically, even fatalities. The incidents underscore the need for ongoing vigilance and proactive measures to minimize the risk of E. coli transmission in settings wher people interact with animals, particularly in petting zoos and similar attractions.