It’s time to add another entry on the list of outbreaks of bacterial pathogens linked to petting zoos and animal exhibits.  The Colorado Department of Public Health and the Environment announced that an outbreak of E. coli O157:H7 in January 2009 was linked to attendance at the National Western Stock Show in Denver.  

The show was open from January 10 to 25, 2009.   The common denominator among all cases of E. coli O157:H7 in the outbreak was attendance at the show.  It appears that the exposures occurred at the “feed the animals” exhibit.  

Depending on counting method and reporting variances, the number of outbreaks at animal exhibits exceeds two dozen.

It doesn’t have to be this way.  

Zoonotic Disease.pngThe CDC has been publishing guidelines designed to prevent or greatly reduce the likelihood of outbreaks in these settings since 2001 when high profile E. coli O157 outbreaks in Pennsylvania and Ohio prompted legislation designed to institute changes in animal exhibits in Pennsylvania.  In the summer of 2004, the National Association of State Public Health Veterinarians and CDC issued an updated set of guidelines and provided specific instructions on how to prevent the spread of zoonotic disease (i.e. disease spread from animals to humans).  Among these:

  • Educate vendors about the risk of the spread of zoonotic disease, and methods of prevention.
  • Educate fairgoers, in multiple formats, of the same risks and methods of prevention.
  • Make special effort to reduce risk among vulnerable populations, especially children.
  • Provide adequate hand-washing facilities;
  • Design animal exhibits to reduce and control human/animal interaction;
  • Closely supervise animal/human interaction, again with special attention to children;

Despite the presence and widespread dissemination of these guidelines, October of 2004 brought one of the most devastating petting zoo E. coli O157:H7 outbreaks yet.  The outbreak at the 2004 North Carolina State Fair led to 108 cases.   Of these, forty-one were laboratory confirmed with E. coli O157:H7.   The ill were almost entirely children, with a number of very severe cases of hemolytic uremic syndrome (HUS).  

The investigation of the outbreak eventually led to the release of a report by the Duke University Institute for Public Policy.  The recommendations in the Duke report were well conceived and well supported.  Still, there was really nothing new about the North Carolina outbreak that informed those recommendations.  The North Carolina outbreak resulted from the failure and/or refusal of those who ran the fair and its exhibits to implement CDC-endorsed guidelines to address a well-documented risk.

Still, there was more to come.  Just months after the North Carolina outbreak a string of E. coli O157:H7 outbreaks linked to a common vendor plagued animal exhibits in Florida.  The AgVenture Farms E. coli O157:H7 outbreak was first recognized after two separate HUS case reports were posted to the Florida Department of Health in March 2005.  The fairs ultimately implicated were the Florida State Fair, the Central Florida Fair and the Florida Strawberry Festival, all in 2005.  A total of 22 confirmed, 45 suspect and 6 secondary cases from 20 Florida counties were identified as victims of this outbreak.  Most cases were infected at either the Central Florida Fair or the Florida Strawberry Festival. Three cases were associated with the Florida State Fair.  Twelve cases developed HUS.

Since that time, the CDC has made updated recommendations for animal exhibitors available, but the tide of outbreaks does not appear to be stemmed.  Another petting zoo in Florida was linked to an E. coli O157:H7 outbreak in 2007.  More recently, a number of children were sickened in the UK in an E. coli O157:H7 outbreak linked to the Godstone farm. 

The saddest part is that these outbreaks can likely be greatly curtailed, if not eliminated.   The guidelines are not only available, but feasible.  Hopefully, those operating these events will get the message soon.