Evaluation of Mycobacterium tuberculosis (TB) Transmission from Asian Elephants to Zoo Employees

Details

• Personal Author:
  Langer, Adam J. ; Martin, Stephen B. Jr. ; Stanton, Marcia L. ; Tomasi, Suzanne E. ; Varela, Kate
• Corporate Authors:
  National Institute for Occupational Safety and Health
• Description:
  The National Institute for Occupational Safety and Health (NIOSH) received a request for a Health Hazard Evaluation from the chief administrative officer of a zoo and aquarium. The request concerned transmission of Mycobacterium tuberculosis (TB) to zoo employees who were working with and around Asian elephants. The 29-acre zoological park was operated by a municipal corporation overseeing parks and recreation services. The zoo's two female Asian elephants were housed in the elephant barn, which was an approximately 3,875 square foot, two-story building with elephant housing on the lower level and employee workspace and animal food storage on the upper level. Adjacent to the elephant barn was a large yard where the elephants were released daily for exercise. The elephant barn and yard are referred to as the "elephant area" for the purpose of this report. At the time of the site visit, approximately 40 employees comprised of elephant keepers, veterinary staff, and facilities and operations staff worked in the barn. Before this outbreak, volunteers worked in the elephant area, but once TB was identified, no volunteers were allowed in the barn and this policy continues to be implemented to limit the number of people potentially exposed to TB. Elephant barn employees participated in annual TB screening conducted offsite at an occupational health provider recommended by the zoo or their primary care provider with either a tuberculin skin test (TST) or blood test (interferon-gamma release assay [IGRA]). In September 2019, eight of twelve zoo employees who worked primarily in the elephant area tested positive for TB infection using IGRA tests
  
  these employees were evaluated for TB and all received a diagnosis of LTBI and were started on LTBI treatment. All employees diagnosed with LTBI had tested negative by TST in 2018. In light of these newly diagnosed infections in employees, both elephants were tested and found to be reactive on the serologic multiantigen print immunoassay (MAPIA) test. Additionally, Mycobacterium tuberculosis DNA was detected by quantitative polymerase chain reaction (qPCR) performed on trunk wash samples obtained in September 2019. In November 2019, TB trunk wash cultures isolated M. tuberculosis from specimens collected from both animals, indicating that both elephants had infectious TB disease. One of the elephants had a long history of being MAPIA-reactive, but the other elephant was newly positive. Both elephants were considered geriatric. For these reasons, the zoo administration believed that the elephants were the probable source of infection for the eight elephant barn employees diagnosed with LTBI in September 2019. In November 2019, a NIOSH team and member of the Centers for Disease Control and Prevention's Division of Tuberculosis Elimination visited the zoo. We completed the following activities during our evaluation: 1. Toured the elephant area (including the elephant barn and yard) and observed workplace practices, including personal protective equipment (PPE) use when working with elephants and in the elephant area. 2. Assessed the elephant barn ventilation system. 3. Conducted voluntary, confidential interviews with 19 employees, including elephant keepers, veterinary staff, and facilities and operations staff. 4. Reviewed the TB exposure control plan for employees including the respiratory protection program, fit testing plan, and draft employee TB surveillance protocol. 5. Met with county and state health department representatives. Our Key Findings: 1. Employees who primarily worked in the elephant area and had contact with the elephants were more likely to test positive for TB infection. 2. At the time of the health hazard evaluation, the zoo had a respiratory protection program and employee TB surveillance program
  
  however, upon review both could be improved. 3. One ventilation system serviced both the elephant housing area and office space in the elephant barn, allowing air from the elephant housing area to enter employee workspaces. 4. Employees needed more information on TB risk and prevention. Our Recommendations: 1. Reduce potential employee exposure to M. tuberculosis. 2. Implement a respiratory protection program and require all employees and volunteers at risk of TB exposure to participate in the zoo's respiratory protection program. 3. Institute an updated TB surveillance program and require that all employees and volunteers potentially exposed to TB participate in the zoo's TB surveillance program. 4. Provide a ventilation system for areas on the upper floor of the barn including the entrance hallway, locker room, restroom, office, and kitchen areas that is separate from the ventilation system for the elephant housing area. 5. Ensure employees understand the hazards associated with working with TB-positive animals and how to protect themselves. 6. Ensure standard procedures for PPE use are clearly identified, communicated to employees, and enforced by supervisors.
  
  
• Subjects:
  Communicable Diseases Health Personnel Occupational Health Personal Protective Equipment Safety Skin Tuberculosis Ventilation Veterinarians
• Keywords:
  Animal Handlers Disease Transmission Elephants Infectious Diseases Latent TB Infection Mycobacterium Tuberculosis OSHA Region 10 Personal Protective Equipment PPE Skin Tests TB Ventilation Ventilation Systems Zoo And Botanical Gardens Zoonoses

  More +
• Source:
  Morgantown, WV: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HHE 2019-0268-3380, 2021 Oct ; :1-37
• Series:
  Health Hazard Evaluation Reports (HHE)
• DOI:
  https://doi.org/10.26616/NIOSHHHE201902683380
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Genre:
  Field Study
• Place as Subject:
  Washington ; OSHA Region 10
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  RHD - Respiratory Health Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  37 pdf pages
• Contributor:
  Elbon, Barbara ; Fechter-Leggett, Ethan ; Fedan, Kathleen ; Glisan, Lisa ; Tift, Brian
• NIOSHTIC Number:
  nn:20063779
• NTIS Accession Number:
  PB2022-100456
• Citation:
  NIOSH [2021]. Evaluation of Mycobacterium tuberculosis (TB) Transmission from Asian Elephants to Zoo Employees. By Varela K, Stanton ML, Tomasi S, Langer AJ, Martin SB. Morgantown, WV: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Health Hazard Evaluation Report 2019-0268-3380,
• Federal Fiscal Year:
  2022
• Peer Reviewed:
  False
• NAICS and SIC Codes:
  712130 - Zoos and Botanical Gardens - (NAICS)
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:e7becdd72e908f8a5ccc0aca6280ff0a81e3eaa2c5a45fe0899a62fecdcae17cb8e2af140b63cd075da42a793780495e8870871509c42206a09e805dbacbb6ef
• Download URL:
  https://stacks.cdc.gov/view/cdc/172316/cdc_172316_DS1.pdf
• File Type:
  [PDF - 2.55 MB ]