Hand Washing: A Key Weapon Against Petting Zoo Pathogens

How best to reduce the risk of zoonotic disease transmission at petting zoos?

Petting zoos are highly popular: some estimates suggest that millions of human-animal contacts occur at state fairs, animal parks, and a host of other public events each year.¹ A strong word of caution is in order, however. Outbreaks of Escherichia coli O157:H7 infection, with resultant hemolytic uremic syndrome, can stem from contact in these settings. But E coli is just the tip of the iceberg. The list of organisms that can be transmitted at petting zoos has been expanded to include Cryptosporidium, Salmonella, Orf virus, Coxiella burnetii (a cause of endocarditis), and Giardia species.¹ Other suspects have been suggested, such as Leptospira interrogans.

Short of abolishing petting zoos, how can we reduce the risk of infection they pose to children? Hand washing is a good idea, but families need training about proper hand hygiene much as a generation of health care providers did.

Weese and coworkers¹ set out (unannounced) to see whether hand washing was a priority at petting zoos. Their results are disturbing. Objects that could be contaminated by animal exposure (such as baby bottles, pacifiers, spill-proof cups, and toys) had ready access to children's mouths, without intervening hygiene. Even though hand hygiene facilities were present at 94% of the sites visited, compliance ranged from 0% to 77%, with a mean of only about 31%.

Now we must not blame only parents, and thereby absolve the proprietors of petting zoos, because there are strategies, not always made available, that can increase compliance:

• Locating the hand hygiene facility near an exit.
• Posting reminder and warning signs (with an emphasis on repetition).
• Having a source of running water available.

The authors stress a number of important points in their discussion. First, public and petting zoo staff education has to be increased. Second, the design of facilities (running water, reminder/warning signs, and hygiene facilities located prominently as families approach exits) is critical. Third, even though animal contact followed by eating has been shown to transmit disease, food vendors were present in some of the immediate areas near the animals. Moreover, the supervisors and staff of the petting zoos said nothing to patrons about decreasing risk by washing or not eating until hygiene was accomplished.

One might ask, since the contemporary cornerstone of infection control involves hand washing, why we have failed to convince the public of its importance. We health care providers have slowly but surely learned ourselves that simple measures can save lives.