According to the CDC estimates, E. coli O157:H7 causes 73,500 illnesses, 2,000 hospital stays, and 60 deaths in the United States every year. The E. coli O157:H7 infection can be transmitted by contaminated food, water and contact with fecal material from infected persons or animals. Many of the infections are associated with consumption of contaminated food or drink, as well as contact with farm animals.

Prior cases of zoonotic disease outbreaks in petting zoos or county fairs indicate that washing hands with soap and water or a sanitizing gel should be performed after contact with farm or other animals. Further, because children will undoubtedly place their fingers or other objects such as toys, baby bottles, pacifiers, or sippy cups in their mouths, these objects should not be allowed in an area with animals. It is almost impossible to avoid contact with animal waste when children or other people attend a farm with a petting zoo. After all, the primary purpose of a petting zoo is to allow children, especially, to interact with and pet the animals. Even strollers taken into animal areas can pick up and carry animal feces, regardless of the degree of sanitation of the premises. Despite these obvious implications, as recently as June 2000, a survey 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!

A recently published observational survey evaluated risk behaviors for transmission of zoonotic diseases at petting zoos, during a period without a recognized disease outbreak. Attendees at six petting zoos were observed for animal and environmental contact, eating or drinking, hand-to-face contact, and use of a hand sanitizer. Hands were examined via bacteriologic culture on some attendees. Environmental samples were collected at 3 petting zoos.

Results included observations on 991 attendees. Of these, 74% had direct contact with animals, 87% had contact with potentially contaminated surfaces in animal contact areas, 49% had hand-to-face contact, and 22% ate or drank in animal contact areas. Thirty-eight percent used a hand sanitizer, and children had better compliance than adults. Results of bacteriologic cultures of hands were negative for Salmonella spp and E. coli O157; but Salmonella spp were isolated from 63% and E. coli O157 from 6% of the environmental samples.

The identification of Salmonella spp and E. coli O157 in petting zoos in the absence of an outbreak confirms that petting zoo settings should be assumed to be contaminated. Animals infected with enteric pathogens may have no signs of illness, and pathogens may be shed intermittently. Resulting environmental contamination can be widespread and persistent, although routine testing or treating of animals is not recommended as a reliable means of preventing the spread of infection.

National recommendations to prevent disease associated with animals in public settings are available, and most venues included in the present study were implementing those guidelines to various degrees. Nevertheless, it was of substantial concern that even with such vigorous efforts on the part of operators to encourage compliance, a third of visitors ignored warnings and did not sanitize their hands.

Rates of eating and drinking varied widely, despite signs prohibiting it in all animal contact areas. In one setting at which half the attendees were observed eating or drinking, an unrelated fair exhibit was offering free ice cream treats at the entrance to the petting zoo.

Recent outbreaks associated with petting zoos have substantial legal implications for the industry. Anecdotal reports of difficulty obtaining insurance and of fairs discontinuing petting zoo exhibits are increasingly common, leading to concerns that important opportunities for education and experience with animals may be lost. While contamination of animal environments cannot be eliminated entirely, more effective implementation of disease-prevention recommendations is critical to ensure these opportunities to interact with animals can continue as safely as possible.

The study findings concluded that high-risk behaviors were common among petting zoo visitors, and disease prevention guidelines were inconsistently followed. The high proportion of visitors observed eating or drinking, having hand-to-face contact in animal contact areas, and failing to sanitize their hands after visiting the petting zoo was disturbing. Veterinarians, venue operators, and public health authorities must work together on targeted education to improve implementation of existing disease prevention guidelines.

References: McMillian et al, J Am Vet Med Assoc 231:1036–1038, 2007; Epi-Log Newsletter 45 (7): 2005; MMWR Weekly, CDC. 54;1277-1280, 2005; Warshawsky et al, Can J Infect Dis. 13: 175-181, 2002; Sargeant et al, Am J Vet Res 61 : 1375-1379, 2000.