Elephant Tuberculosis Diagnosis: Implications for Elephant Management in Asian Range Countries
Abstract
Serologic tests including the ELISA, MAPIA (multi-antigen print immunoassay), and a rapid test (Vet TB Stat-Pak® [Chembio Diagnostic Systems, Inc., Medford, NY, USA]) have recently been developed and show great promise for the diagnosis of tuberculosis (TB) in elephants.1,3-7 These serologic tests detect antibodies to antigens of Mycobacterium tuberculosis complex organisms and in some cases have detected infection years in advance of active disease and mycobacterial shedding.
The diagnosis of active TB (by culture) or serologic conversion presents management challenges for captive elephants in Asian range countries. Of the 2 billion humans worldwide infected with TB, fewer than 10% will develop active disease.2 This figure is unknown for elephants. The identification and management of infected elephants has ramifications for elephants and humans alike, and issues such as public health and tourism may be impacted.
TB is endemic among humans in Asia, and where there is intermingling of elephants and humans, both species may act as reservoirs for disease transmission. The various situations in which elephants are kept in Asia (government owned, privately owned, festivals, temples, zoos, etc.) make it difficult to develop a management strategy that will address all circumstances. Other concerns are the cost of treatment for an elephant (∼$50,000 USD) and appropriate monitoring in resource-poor countries.
The authors have recently undertaken the screening of 120 elephants in Nepal to further evaluate the above-mentioned (and other) diagnostic tests. To our knowledge, this is the first organized, large-scale initiative to screen Asian elephants within a range country. Preliminary discussions regarding the management of both culture and serologically positive government-owned and privately owned elephants in Nepal have been initiated and may serve as a starting point for other countries as more elephants are screened within Asia. Basic options for active (culture-positive) cases include (1) treatment, (2) segregation or (3) euthanasia. Options for latent disease (culture-negative, serologically positive) cases include (1) treatment, (2) segregation and monitoring for active disease and (3) euthanasia. The particular ownership/husbandry system, available resources and cultural constraints may dictate final management choices in range countries.
Acknowledgments
The Nepal Elephant Tuberculosis Research Project was made possible with support from the Dodge Foundation, the Mazuri Fund, the Walter J. Ernst Memorial Fund, Elephant Care International, and Busch Gardens, Tampa.
Literature Cited
1. Anon. 2005. Summary Elephant Tuberculosis Research Workshop, Orlando, FL; May 21–22, 2005. Accessed at Elephant Care International (http://elephantcare.org, April 24, 2006: http://www.elephantcare.org/protodoc_files/2005/Elephant%20Tuberculosis%20Research%20Workshop%20May%2005.pdf. (VIN editor: This link was not accessible as of 1-25-21.)
2. Boomershine, C.S., and B.S. Zwilling. 2000. Stress and the pathogenesis of tuberculosis. Clin. Microbiol. Newsletter 22(23):177–182.
3. Larsen, R.S., M. Kay, J.Triantis, and M.D. Salman. 2005. Update on serological detection of Mycobacterium tuberculosis infection in Asian elephants. Proc. Am. Assoc. Zoo Vet. Pp. 62–63.
4. Larsen, R.S., M.D. Salman, S.K. Mikota, R. Isaza, R., R.J. Montali, and J.Triantis. 2000. Evaluation of a multiple-antigen enzyme-linked immunosorbent assay for detection of Mycobacterium tuberculosis infection in captive elephants. J. Zoo Wildl. Med. 31(3):291–302.
5. Lyashchenko, K., M. Miller, and W.R. Waters. 2005. Application of MAPIA (Multiple Antigen Print Immunoassay) and rapid lateral flow technology for tuberculosis testing of elephants. Proc. Am. Assoc. Zoo Vet. Pp. 64–65.
6. Lyashchenko, K., M. Singh, R. Colangeli., and M.L. Gennaro. 2000. A multi-antigen print immunoassay for the development of serological diagnosis of infectious disease. J. Immunol. Meth. 242:91–100.
7. Mikota, S.K. Tuberculosis in elephants. In: Fowler, M. and Miller, R.E., eds. Zoo and Wild Animal Medicine. 6th ed. Elsevier, St. Louis, MO, (in press).