Research on Fair and Petting Zoo OutbreaksThe concept of zoonotic diseases is extremely well established and has a long history. Case studies have clearly established a causal link between human enteric pathogenic illnesses and exposure to animals (Szita, 1980; Trevena, 1999). The case studies have verified the transmission of enteric pathogens, such as Campylobacter jejuni, Cryptosporidium, and E. coli O157:H7 from animals to humans at common public venues such as petting zoos, open farms, and animal exhibits at state and county fairs.
There is a 2.45-fold increased risk factor for sporadic cases of verocytotoxin-producing Escherichia coli O157 (VTEC) infection when humans have contact with animals in a farm environment. One particularly strong paper establishing such a causal relationship was published by O’Brien et al in November-December of 2001.
Studies in the UK have shown the majority of outbreaks linked to farm animal contact are caused by VTEC and Cryptosporidium spp. Both pathogens present a seasonal pattern with VTEC incidence highest in the late summer and Cryptosporidium incidence highest in the spring. These studies have also found that places with improper hand-washing facilities are more likely to be the source of an outbreak. In particular, providing only alcohol-based hand sanitizers is inadequate as Cryptosporidium parasites are not killed by them.