Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: March 7, 2005
Publication Date: June 1, 2005
Citation: Keen, J.E., Meehan, T., Durso, L.M. 2005. Fecal prevalence of shiga-toxigenic E. coli O157 and Salmonella enterica of animals in contact areas of United States zoos accreditied by the American Zoo and Aquarium Association. [abstract] American Society of Microbiologists. p. 160.
Outbreaks of shiga-toxigenic E coli (STEC) O157 have been associated with human-animal contact in public settings, including open farms, State and County Fair livestock exhibits and petting zoos. These outbreaks have sickened hundreds of people, sometimes severely, and caused at least two deaths in the past 5 years. Human-animal contact settings vary in hygiene and sanitation practices, the degree of supervision, the extent of animal contact permitted, and in facility design. Recent surveys have shown that livestock on farms and at fairs often shed both STEC O157 and Salmonella in their feces. Our goal was to estimate American Zoological Association (AZA)-institutional and individual animal fecal prevalence rates for both pathogens. We hypothesized that the standardized conditions and generally higher levels of hygiene in AZA contact settings would result in lower pathogen prevalence compared to animals in production or fair settings.
AZA zoos with human-animal contact areas (such as children's zoos) were recruited to participate voluntarily and confidentially. Feces was collected in summer of 2003 and 2004 from a census of animals in contact areas and cultured for Salmonella and STEC O157.
Thirty-six zoos provided feces from 997 animals, including 526 goats, 192 sheep, 59 equids, 49 cattle, 45 pigs, 33 deer, 26 llamids, 17 birds, 16 rabbits, 10 rodents, 5 tortoises and 3 carnivores. STEC O157 was isolated from one quarantined bovid. Salmonella was isolated at 4 zoos from 3 goats, 1 horse, 1 bovine and 1 giraffe. STEC O157 or Salmonella was isolated from an animal at 5 of 36 contact areas (13.9%).
Fecal prevalence of STEC O157 (1/997 = 0.1%) and Salmonella (6/997 = 0.6%) was very low in animals connected with AZA contact areas, both in absolute terms and relative to the high prevalence (often >25%) for these pathogens in farm or fair setting. Contact areas at AZA zoos appear to present a low zoonotic risk to human visitors compared to other settings where human-animal contact may occur. Understanding the basis for this low prevalence may have future application towards lowering enteric zoonotic bacteria prevalence in animals in farm settings.