Petting zoos are very common in the UK (as in many other regions), where approximately 2 million people visit 1000 different petting zoos every year. While the vast majority of petting zoo visits are simply pleasant outings associated with no problems, some people leave with more than just memories… they leave with an infectious disease.  A letter in the latest edition of Emerging Infectious Diseases (Gormley et al 2011) describes one of the diseases people can pick up at petting zoos: cryptosporidiosis.

From 1992-2009, 55 outbreaks of intestinal infections associated with petting zoos were reported in England and Wales. (There were presumably many more unidentified cases or even outbreaks.) Of these, 55% were caused by E. coli O157.  The second most common cause was Cryptosporidium, a protozoal parasite that is commonly found in feces of calves and lambs, which was responsible for 42% of the outbreaks and affected 1078 people. (Again, this is probably an underestimation of the true numbers because typically there are many undiagnosed or unreported cases of illness for every case that is identified). The number of people involved ranged from 2-541 per outbreak. Twenty-nine people were hospitalized due to the infection.

Factors associated with outbreaks were things that we know are issues with petting zoos:

• Contact with young lambs, calves or kids
• Inadequate hand hygiene facilities

Cryptosporidium outbreaks were also more common in the spring, as opposed to E. coli outbreaks which were more common in the summer. This may be explained by the association of the pathogen with contact with young calves, lambs and kids, since these animals are mainly born in the spring.

Alcohol-based hand sanitizers, while excellent for most bacteria, are ineffective against Cryptosporidium.  This can also be a contributing factor to outbreaks of cryptosporidiosis, particularly if hand washing stations are replaced with hand sanitizers. While alcohol-based hand sanitizers are certainly better than nothing, their usefulness is limited when resistant pathogens (such as Cryptosporidium) may be present, and when peoples’ hands might be contaminated with large amounts of dirt or other debris (e.g. feces).

Petting zoos can be great events, particularly for kids. However, kids, especially young kids (less than five years of age), are at high risk for certain infectious diseases they may encounter at such venues. While petting zoos seem to be improving and governments are paying more attention to making them safer, visitors need to look out for themselves.

• Make sure a hand hygiene station, preferably a hand washing station, is available. Do this before you touch animals.
• Always wash your hands after leaving the petting zoo, regardless of whether or not you touched an animal (since other surfaces you touched may have been contaminated).
• Do not have contact with young calves, lambs, kids (i.e. baby goats) or poultry.
• Do not have contact with diarrheic animals, or animals that appear to have any other health problems.
• Don’t take food, drink or anything that might go into a child’s mouth (e.g. baby bottles) into the petting zoo area.
• Closely supervise children.
• If you see a poorly equipped or run event, don’t be afraid to contact your local public health office. While most petting zoos seem to be improving, some are still pretty bad and may need to be forced to do things right.