Cause of Zoo Knoxville Reptile Deaths Consistent with Toxic Agent

Communications Director

Kristin Farley
(865) 215-2589

400 Main St., Room 691
Knoxville, TN 37902

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Cause of Zoo Knoxville Reptile Deaths Consistent with Toxic Agent

Posted: 05/12/2017
Necropsy results indicate the cause of death of 34 reptiles at Zoo Knoxville in March was most likely due to a toxic agent.

Necropsies of the affected animals showed many animals had swollen blood vessels and changes in the liver and the heart.  Veterinarians at the U.T. College of Veterinary Medicine determined the combination of these findings, along with the acute death of multiple animals, is most consistent with a toxic agent. The blood of affected and unaffected animals was tested for multiple toxins and none were found.  Some substances such as carbon monoxide and carbon dioxide, as well as electrical shock, cannot be tested for after death and thus cannot be ruled out.  No infectious agents were identified during the analysis.

The event occurred in a single building in the zoo’s reptile complex.  Zoo Knoxville conducted extensive testing of air quality and the building’s HVAC and temperature monitoring systems.  All air quality tests in the building were within normal ranges.  A thermostat was found to be malfunctioning intermittently, but the temperature monitoring system, which alerts zoo staff if temperatures in the building exceed or fall below acceptable ranges, worked reliably during all tests.   

During the repeated systems testing, staff were unable to replicate an event consistent with the suspected cause, and the decision was made to take the building out of use as the safest course of action.

“We had hoped for a definitive answer to what happened so we can make sure it never occurs again,” said Zoo Knoxville President and CEO Lisa New.  “Unfortunately, there is no clear-cut answer to this situation and therefore we will not take the risk of housing animals in this building.  While this does affect the number of animals we have on view in the short term, this will in no way impact the internationally recognized work our herpetologists do to save critically endangered reptiles.  That will continue.  If there is a positive to come from this, it is the affirmation that the conservation work we do is important to our community, and it strengthens our commitment and urgency to construct a new, state-of-the-art reptile education center as part of our current capital campaign.”

Zoo Knoxville suffered the loss of 34 reptiles in an event that happened between the hours of 5:00 p.m. Tuesday, March 21 and 8:00 a.m. Wednesday, March 22, 2017.  The other buildings in the zoo’s reptile facility were not impacted and continue to be used for housing and public viewing.          
Zoo Knoxville is a nonprofit entity situated on 53 wooded acres just east of downtown Knoxville. Zoo Knoxville features exhibits of wild animals in natural habitats and is world renowned for its efforts in conservation and species survival. Zoo Knoxville is nationally accredited by the Association of Zoos and Aquariums (AZA) and is committed to the highest standards in animal care and well-being, ethics, conservation, and education. Knoxville’s largest attraction, the zoo is open every day except Christmas Eve and Christmas Day.  Currently, the zoo is open Monday through Friday from 9:30 a.m. until 4:30 p.m. and Saturday and Sunday from 9:30 a.m. until 6:00 p.m.  Admission and ticket sales stop one-hour before the zoo closes. For more information visit