E. coli O157:H7
A 2003 study on the prevalence of E. coli O157:H7 in livestock at 29 county and 3 large state agricultural fairs in the United States found that E. coli O157:H7 could be isolated from 13.8 percent of beef cattle, 5.9 percent of dairy cattle, 3.6 percent of pigs, 5.2 percent of sheep, and 2.8 percent of goats. Over seven percent of pest fly pools also tested positive for E. coli O157:H7 (Keene et al, 2003).According to the National Association of State Public Health Veterinarians’ “Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, 2013”:
The primary mode of transmission for enteric pathogens [like E. coli O157:H7] is fecal-oral. Because animal fur, hair, feathers, scales, skin and saliva harbor fecal organisms, transmission can occur when persons pet, touch, feed or are licked by animals. Transmission also has been associated with exposure to contaminated animal bedding, flooring, barriers, other environmental surfaces, and contaminated clothing and shoes. In addition, illness has resulted from fecal contamination of food, including raw milk and drinking water.
Pathogenic Properties of E. coli O157:H7:
Some strains of Escherichia coli, such as serotype E. coli O157:H7, can produce potent cytotoxins called Shiga toxins (Stx). The natural hosts of Shiga toxin-producing E. coli (STEC) are farm and wildlife ruminants i.e. cows, sheep, and goats.
The most prominent symptom of human infection with Shiga toxin-producing E. coli O157:H7 is hemorrhagic colitis. Symptoms include painful, bloody diarrhea and abdominal cramps. In some patients, hemorrhagic colitis progresses into hemolytic uremic syndrome (HUS). HUS is a serious illness which in many cases can be fatal. Thus E. coli O157:H7 has been considered as a causative agent for producing serious health threats, especially for children.
Rate of E. coli O157:H7-Caused Illnesses:
According to CDC estimates, Shiga toxin-producing E. coli causes over 175,000 illnesses in the United States every year. E. coli O157:H7 causes about 36% of all infections—or 63,000 cases—and non-O157 STEC cause the rest. Just over 2,000 hospitalizations and 20 deaths can be attributed to STEC infections annually. E. coli O157:H7 can be transmitted by contaminated food, water, and contact with fecal material from infected persons or animals. Many infections are associated with consumption of contaminated food or drink; however, contact with farm animals has also been identified as a risk factor for E. coli O157:H7 infection.
Controlling E. coli at fairs and petting zoos:
Direct human-animal contact may take place at fairs and petting zoos, and in some past outbreak-situations a strong association with a state or county fair or petting zoo could be established. As of June 2000, a survey out of 44 state and territorial public health departments indicated that none had laws to control exposure of humans to enteric pathogens at venues where the public comes into contact with farm animals (MMWR Weekly, April, 2001). Although no federal laws address the risk of zoonotic disease at venues where the public has contact with animals, some states have enacted such laws.
In 2002, the Pennsylvania legislature responded to an E. coli outbreak traced to a Montgomery County petting zoo that occurred in 2000 by unanimously passing legislation that became effective in early 2003. The passage of Senate Bill No. 1325 made Pennsylvania the lone state to put into law measures to protect visitors at fairs and petting zoos from E. coli and other zoonotic diseases. The law stipulates that animal exhibitions provide hand washing facilities, and post notices on the need for hand washing in addition to warning about the dangers of more than 75 zoonotic diseases. Exhibitors out of compliance with the law can be fined up to $500 for each violation.
In 2004, the North Carolina Department of Health and Human Services (NCDHHS) responded to a large E. coli O157:H7 outbreak at the 2004 North Carolina State Fair by requesting an assessment of whether the state should regulate petting exhibits to prevent transmission of disease and if so, how, from the Terry Sanford Institute of Public Policy at Duke University. In May 2005, the Terry Sanford Institute released a report for the NCDHHS titled, “E. coli outbreak creates need for government regulation”, which concluded in part:
We recommend two of our implementation options: (1) issuing guidelines and (2) pursuing legislative action [to prevent further E. coli outbreaks among fair attendees]. These recommendations address both short-term and long-term needs. We propose considering these two recommendations as a single implementation package, since neither would sufficiently address the issue on its own. We do not recommend writing rules because they are enforced on a complaint-only basis.
In keeping with the recommendations, the North Carolina legislature passed Aedin’s Law in July of 2005. The law requires petting zoos to obtain permits and undergo inspections. The North Carolina Department of Agriculture also hired two inspectors specifically to oversee petting zoos.
Legislation and the implementation of guidelines and regulations will reduce the likelihood of zoonotic disease outbreaks in Pennsylvania and North Carolina, but most states have not yet enacted the same measures, and outbreaks will continue to happen.
