Outbreak of Mycobacterium tuberculosis Among Employees of an Elephant Refuge

1. Outbreak of Mycobacterium tuberculosisAmong Employees of an Elephant Refuge Rendi Murphree, PhD CDR, USPHS Tennessee Department of Health EIS Field Assignments Branch, DAS (proposed), SEPDPO (proposed)

2. Background

3. Captive Elephants in North America 270 Asian elephants 12% have active TB disease 220 African elephants 2% have active TB disease

4. Tuberculosis in Humans and Elephants

5. Tuberculosis in Humans and Elephants

6. Tuberculosis in Humans and Elephants

7. Tuberculosis in Humans and Elephants

8. The Elephant Refuge in Tennessee

9. Elephant Refuge • South-central Tennessee • Founded in 1995 • Care of sick, old, abused or needy elephants • Nonprofit organization accredited, regulated and closed to the public

10. Elephant Refuge • 2700 acres with 3 distinct areas • 2 African elephants • 6 Asian elephants • 1 “cured” of TB disease in 2006 • 7 Asian elephants • All quarantined since 2006 for exposure to TB disease

13. The Outbreak Notification October, 2009 5 tuberculin skin test (TST) conversions among employees of the refuge Investigation objectives Determine extent of outbreak Identify risk factors for TST conversion in humans Prevent ongoing transmission

14. Methods

15. Cohort Study Interviews Review occupational health records TST screening

16. Onsite Assessment Facility design Barn management Husbandry practices

17. Outbreak Case Definition Refuge employee or intern, 2006–2009 At least one negative TST, followed by a TST of ≥5-mm induration

18. Results

19. Employee Cohort, 2006–2009 • 46 employees interviewed • 30 caregivers • 11 administrators • 5 maintenance workers • 9 (20%) had positive TST • 8 had conversion during 2009

20. Risk Factors for TB Among Refuge Employees, 2006–2009 *Risk estimate not computed when at least one cell contained a zero

21. Risk Factors for TB Among Refuge Employees, 2006–2009 *Risk estimate not computed when at least one cell contained a zero

22. Risk Factors for TB Among Refuge Employees, 2006–2009 *Risk estimate not computed when at least one cell contained a zero

23. Risk Factors for TB Among Refuge Employees, 2006–2009 *Risk estimate not computed when at least one cell contained a zero

24. TST Conversion Timeline Among Quarantine Facility Employees, 2009

25. TST Conversion Timeline Among Quarantine Facility Employees, 2009

26. Quarantine Barn Admin Area Quarantine Facility

27. Quarantine Barn Admin Area Quarantine Facility Elephant with TB

28. Characteristics of Quarantine Facility Employees, 2009

29. Characteristics of Quarantine Facility Employees, 2009

30. Characteristics of Quarantine Facility Employees, 2009

31. Observation: Delay in Recognizing Increased Risk

32. Observation: Delay in Recognizing Increased Risk

33. Observation:High Risk Practices

34. Observation:Unrestricted Air Flow

35. Conclusions

36. Findings • Zoonotic Mtb transmission from an elephant to humans • Insufficient infection control • Inconsistent use of respirators • Aerosol generating procedures • Unrestricted air flow

37. Limitations • Small study population • 11 employees not contacted • Formal air flow studies pending

38. Recommendations Relocate nonessential personnel Increase use of respirators Revise infection control practices

39. Elephant refuge employees and leadership Tennessee Wildlife Regulatory Authority Walter Cook TN South-central Regional Health Office Lang Smith, MD Joy Smith, RN Lewis County Health Department Tennessee Department of Health John R. Dunn, DVM, PhD Jon V. Warkentin, MD, MPH Timothy F. Jones, MD Vanderbilt University School of Medicine William S. Schaffner, MD CDC W. Randolph Daley, DVM, MPH Acknowledgments The findings and conclusions in this report are those of the author and do not necessarily represent the official position of the Centers for Disease Control and Prevention.